taxonID	type	description	language	source
AD26453DFFA3FFB2FF4E0F4EFE3BDF35.taxon	description	(Figs 1, 2 A – B; Table 1)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFA3FFB2FF4E0F4EFE3BDF35.taxon	materials_examined	Type material. Holotype male (slide # Type- 8452) and one male paratype (slide # Type- 8453) deposited in the invertebrate type collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Additional material. Two males and five females (slides # 129907 - 129909) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Type locality. Coarse sediment with algae from 45 – 55 m deep, Skagerrak, off the west coast of Sweden (N 58 ° 17 ' 32 '', E 11 ° 11 ' 24 ''), 09 August 2011, legit O. Holovachov (two males). Additional localities. Gravel, mud and algae from 30 – 70 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 14 '', E 11 ° 05 ' 00 ''), 09 August 2011, legit O. Holovachov (two males and five females).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFA3FFB2FF4E0F4EFE3BDF35.taxon	etymology	Etymology. The specific epithet " primus " is translated as " the first " and refers to the sequential number of the new species described in this publication.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFA3FFB2FF4E0F4EFE3BDF35.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; straight or ventrally curved upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 1.1 – 1.8 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 1 – 2 µm wide at mid-body; originating at level of metacorpus (posterior to the first body pore) and extending posteriorly to proximal part of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually three pairs of body pores are present along pharyngeal region; several body pores scattered over rest of the body. Anteriormost body pore located at level of stoma base or procorpus. Labial region rounded, lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla setiform, equal to 40 – 60 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located at level of middle of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system present; excretory pore located posterior to nerve ring, at level of middle of isthmus. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (shorter and more curved ventrad in male), elongate-conoid proximally and subcylindrical distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Three pairs of short setae emerging through first, second and third pairs of body pores. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate conoid calamus and ovoid manubrium. Gubernaculum plate-like, with caudal apophysis. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip and four alveolar supplements extending for 55 – 67 µm from cloaca towards anterior end; midventral tubular supplements absent. Alveolar supplements without inner sclerotized ring. Posteriormost alveolar supplement 11 – 14 µm anterior to cloaca, anterior to spicules. Anteriormost alveolar supplement 195 – 236 µm from anterior end, at level of posterior part of intestine. Sublateral precloacal and caudal sensilla present: two (one pair) precloacal setae at level of spicules and usually eight (four pairs) caudal setae arranged in two subventral and two subdorsal pairs. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 48 – 66 µm long (equal to 11.4 – 13.9 % of total body length), located on right-hand side of intestine (n = 5), posterior genital branch 47 – 117 µm long (equal to 9.9 – 25.6 % of total body length), located on left-hand side of intestine (n = 5). Oviduct a narrow tube. Two offset, oval, sac-like spermathecae located on each (right and left) side of each (anterior and posterior) gonoduct. Spermathecae usually filled with oval spermatozoa. Uterus a wide and short tube. Vagina straight, 0.3 times vulval body diameters long; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae absent. Vulva midventral. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Supplements absent. Rectum 1.1 – 1.4 anal body diameters long; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFA3FFB2FF4E0F4EFE3BDF35.taxon	diagnosis	Diagnosis. Leptolaimus primus sp. n. is particularly characterised by the 319 – 472 µm long body; rounded labial region continuous with body contour; cephalic setae 1.5 – 2.0 µm long; amphid located 7.0 – 11.5 µm from anterior end; first body pore located 18.5 – 28.0 µm from anterior end; lateral field originating 35 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male without tubular and with four alveolar supplements, alveolar supplements without sclerotized inner ring; spicules arcuate and 13.5 – 16.0 µm long. Relationships. The new species belongs to a group of species in which males have only alveolar supplements and include Leptolaimus pumicosus Vitiello, 1970 and L. pocillus de Bovée, 1974. Leptolaimus primus sp. n. differs from both species in having fewer alveolar supplements (four in L. primus sp. n. vs. 35 in L. pumicosus and 11 in L. pocillus) and shorter spicules (13.5 – 16.0 µm in L. primus sp. n. vs. 20 µm in L. pumicosus and 21 – 22 µm in L. pocillus). Furthermore, it differs from L. pumicosus in the shape of gubernaculum (with caudal apophysis vs. with dorsal apophysis in L. pumicosus) and from L. pocillus in the shape of alveolar supplements (without sclerotized ring vs. with sclerotized ring in L. pocillus).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFAEFFB0FF4E0A03FECCD9DF.taxon	description	(Figs 2 C – D, 3; Table 2)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFAEFFB0FF4E0A03FECCD9DF.taxon	materials_examined	Material examined. 17 males and 30 females (slides # 129910 – 129920) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Habitat and locality. Sediment (top layer), Baltic off the east coast of Sweden (N 58 ° 46 ' 00 '', E 17 ° 49 ' 52 ''), 26 May 2011, legit C. Raymond (15 males and 30 females); sediment (top layer), Baltic off the east coast of Sweden (N 59 ° 27 ' 15 '', E 19 ° 19 ' 16 ''), 22 May 2011, legit C. Raymond (1 male and 3 females); soft clay (top layer) from 64 m deep, Bothnian sea off the east coast of Sweden (N 63 ° 23 ' 21 '', E 19 ° 51 ' 27 ''), 26 May 2011, legit J. Albertsson (1 male and 3 females).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFAEFFB0FF4E0A03FECCD9DF.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; straight or ventrally curved upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 1.4 – 2.1 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 1.5 – 2.5 µm wide at mid-body; originating at level of procorpus (anterior to, at level with or just posterior to first body pore) and extending posteriorly to middle of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually three pairs of body pores are present along pharyngeal region; several body pores scattered over rest of the body. Anteriormost body pore located at level of procorpus. Labial region flattened, lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla papilliform. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located at level of middle of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system present; excretory pore located just posterior to nerve ring. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (shorter and more curved ventrad in male), elongate-conoid, gradually narrowing distally, often with clavate tail tip. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. One pair of short and two pairs of long setae emerging through first, second and third pairs of body pores. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate conoid calamus and ovoid manubrium. Gubernaculum arcuate, plate-like, with long arcuate dorsal apophysis that curves towards anterior end. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, four evenly spaced midventral tubular supplements extending for 64 – 73 µm from cloaca towards anterior end; 17 – 25 alveolar supplements. Tubular supplements with ovoid " manubrium " and straight cylindrical body; tips of tubules with hook-like projections on their posterior side. Posteriormost tubular supplement 17 – 20 µm anterior to cloaca, anterior to spicules. Alveolar supplements with inner sclerotized ring. Anteriormost alveolar supplement 79 – 94 µm from anterior end, at level of isthmus. Sublateral precloacal and caudal sensilla present: two (one pair) precloacal setae at level of spicules and usually eight (four pairs) caudal setae arranged in two subventral and two subdorsal pairs. Additional individual setae may be present on the dorsal body side anterior or posterior to cloaca. A pair of alveole-like invaginations with sclerotized lining is located on the ventral side of the tail, just anterior to the second pair of subventral caudal setae. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 66 – 93 µm long (equal to 12.5 – 15.3 % of total body length), located on right-hand side of intestine (n = 5), posterior genital branch 67 – 107 µm long (equal to 12.5 – 17.6 % of total body length), located on left-hand side of intestine (n = 5). Oviduct a narrow tube. Two offset, oval, sac-like spermathecae located on each (right and left) side of each (anterior and posterior) gonoduct, obscure in some specimens. Spermathecae usually filled with oval spermatozoa. Uterus a wide and short tube. Vagina straight, 0.3 – 0.4 times vulval body diameters long; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae present, T-shaped. Vulva midventral. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Supplements absent. Rectum 1.4 – 1.9 anal body diameters long; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFAEFFB0FF4E0A03FECCD9DF.taxon	diagnosis	Diagnosis (supplemented with literature data). Leptolaimus papilliger is particularly characterised by the 350 – 609 µm long body; rounded labial region continuous with body contour; cephalic setae papilliform; amphid located 6.0 – 10.0 µm from anterior end; first body pore located 25.0 – 32.0 µm from anterior end; lateral field originating 21.5 – 36.5 µm from anterior end; female without supplements, vagina with T-shaped pars refringens, vulva midventral; male with four tubular and 12 – 27 alveolar supplements, tubular supplements straight with hook-like tips, alveolar supplements with sclerotized ring; spicules arcuate and 13.0 – 19.0 µm long.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFAEFFB0FF4E0A03FECCD9DF.taxon	discussion	Remarks. Current material agrees well with the original description in general morphology, measurements, shape of labial region, spicules and gubernaculum, and the number of supplements. Unfortunately, the original description of this species is insufficiently illustrated to allow any further comparison. Specimens described by Lorenzen (1969) are smaller (405 – 520 µm vs. 491 – 609 µm in current population) with marginally smaller spicules (13.0 – 17.0 µm vs. 15.0 – 19.0 µm in current specimens). The population from the Far East is much smaller than current population from the Baltic (350 – 480 µm vs. 491 – 609 µm in current population), has fewer alveolar supplements (12 – 14 vs. 17 – 25 in current specimens) and has lower values for some measurements, but does not show sufficient deviation to be assigned a different species (Alekseev, 1981).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFADFFB4FF4E0B73F872DA1D.taxon	description	(Figs 2 E – F, 4; Table 3)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFADFFB4FF4E0B73F872DA1D.taxon	materials_examined	Material examined. 3 males and 4 females (slides # 129911, 129921 – 129923) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Habitat and locality. Sediment (top layer), Baltic of the east coast of Sweden (N 58 ° 46 ' 00 '', E 17 ° 49 ' 52 ''), 26 May 2011, legit C. Raymond (3 males and 4 females).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFADFFB4FF4E0B73F872DA1D.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; ventrally curved upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 1.3 – 1.9 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 2.0 – 3.0 µm wide at mid-body; originating at level of isthmus (posterior to first body pore) and extending posteriorly to middle of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually three pairs of body pores are present along pharyngeal region; several body pores scattered over rest of the body. Anteriormost body pore located at level of procorpus. Somatic sensilla absent in female, present in male (see below). Labial region rounded, continuous with body contour, lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla setiform, equal to 20 – 40 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located at level of middle of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system present; excretory pore located posterior to nerve ring. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (shorter and more curved ventrad in male), elongate-conoid, gradually narrowing distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Three short setae emerging through first, second and third pairs of body pores. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate conoid calamus and ovoid manubrium. Gubernaculum plate-like, with paired dorsal apophysis. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, six – seven evenly spaced midventral tubular supplements extending for 117 – 130 µm from cloaca towards anterior end; 25 – 26 alveolar supplements. Tubular supplements straight or weakly arcuate, with dentate tips. Posteriormost tubular supplement 27 – 32 µm anterior to cloaca, anterior to spicules. Alveolar supplements with broad inner sclerotized ring. Anteriormost alveolar supplement 89 – 97 µm from anterior end, at level of isthmus. Sublateral caudal sensilla present: usually eight (four pairs) caudal setae arranged in two subventral and two subdorsal pairs; precloacal setae absent. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 78 – 117 µm long (equal to 12.1 – 16.8 % of total body length), located on right-hand side of intestine (n = 2), posterior genital branch 91 – 122 µm long (equal to 14.5 – 17.5 % of total body length), located on left-hand side of intestine (n = 3). Oviduct a narrow tube. One offset, oval, sac-like spermatheca located on right side of anterior gonoduct and one on left side of posterior gonoduct. Spermathecae often filled with oval spermatozoa. Uterus a wide and short tube. Vagina straight, 0.3 times vulval body diameters long; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae present, angular. Vulva midventral. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Supplements absent. Rectum 1.4 – 1.7 anal body diameters long; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFADFFB4FF4E0B73F872DA1D.taxon	diagnosis	Diagnosis (supplemented with literature data). Leptolaimus cupulatus is particularly characterised by the 543 – 698 µm long body; rounded labial region continuous with body contour; cephalic setae 1.0 – 2.0 µm long; amphid located 8.5 – 11.0 µm from anterior end; first body pore located 27.0 – 33.0 µm from anterior end; lateral field originating at level of isthmus; female without supplements, vagina with angular pars refringens, vulva midventral; male with 6 – 8 tubular and 25 – 27 alveolar supplements, tubular supplements straight with dentate tips, alveolar supplements with sclerotized ring; spicules arcuate and 16.0 – 20.0 µm long.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFADFFB4FF4E0B73F872DA1D.taxon	discussion	Remarks. Current material agrees well with the type specimens in general morphology and measurements, shape of supplements, spicules and gubernaculum, with only minor differences in few body measurements.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFA8FFABFF4E09E3F86FDD17.taxon	description	(Figs 2 G – H, 5; Table 4)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFA8FFABFF4E09E3F86FDD17.taxon	materials_examined	Material examined. 33 males and 64 females (slides # 129924 – 129937, 129963) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Habitat and locality. Muddy sediment from 53 m deep, Skagerrak off the west coast of Sweden (N 58 ° 20 ' 06 '', E 11 ° 09 ' 24 ''), 09 August 2011, legit O. Holovachov (two males and 20 females); gravel, mud and algae from 30 – 70 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 14 '', E 11 ° 05 ' 00 ''), 09 August 2011, legit O. Holovachov (three males and three females); muddy sediment from 55 – 70 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 19 '', E 11 ° 04 ' 55 ''), 09 August 2011, legit O. Holovachov (one male and one female); soft mud from 30 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 25 '', E 11 ° 27 ' 30 ''), 11 August 2011, legit O. Holovachov (five males and 11 females); soft mud from 44 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 37 '', E 11 ° 27 ' 43 ''), 11 August 2011, legit O. Holovachov (21 male and 29 females).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFA8FFABFF4E09E3F86FDD17.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; ventrally arcuate upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 2.0 – 2.5 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 1.5 – 2.5 µm wide at mid-body; originating at level of procorpus or metacorpus (posterior to first body pore) and extending posteriorly to middle of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually four pairs of body pores are present along pharyngeal region; several body pores scattered over rest of the body. Anteriormost body pore located at level of procorpus. Labial region truncate-conoid, continuous with body contour, lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla setiform, equal to 40 – 100 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea rounded, located at level of middle of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system indistinct. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (more curved ventrad in male), elongate-conoid, gradually narrowing distally with subcylindrical terminal part. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Three long setae emerging through second, third and fourth pairs of body pores. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate conoid calamus and ovoid manubrium. Gubernaculum plate-like, with dorsal apophysis. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, usually five (rarely four or six) evenly spaced midventral tubular supplements extending for 136 – 153 µm from cloaca towards anterior end; usually six (rarely seven) alveolar supplements. Tubular supplements almost straight, with expanded dentate tips; surrounded by sclerotized ring. Posteriormost tubular supplement 28 – 33 µm anterior to cloaca, anterior to spicules. Alveolar supplements with inner sclerotized ring, and with short and narrow sclerotized tube connected to unicellular gland. Anteriormost alveolar supplement 130 – 147 µm from anterior end, at level of anterior part of intestine. Sublateral precloacal and caudal sensilla present: two (one pair) precloacal setae at level of cloaca and usually eight (four pairs) caudal setae arranged in two subventral and two subdorsal pairs. One subventral pair of papilliform sensilla located at the bases of the second (from cloaca) pair of caudal setae. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 57 – 76 µm long (equal to 10.0 – 12.6 % of total body length), located on right-hand side (n = 6) or lefthand side (n = 1) of intestine, posterior genital branch 52 – 74 µm long (equal to 8.5 – 13.0 % of total body length), located on left-hand side (n = 6) or right-hand side (n = 1) of intestine. Oviduct a narrow tube. Two offset, oval, saclike spermathecae located on each (right and left) side of each (anterior and posterior) gonoduct; the spermatheca on one side of the gonoduct is often more developed than on the other side. Spermathecae often filled with oval spermatozoa. Uterus a wide and short tube. Vagina straight; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae present, triangular. Vulva usually right-ventrosublateral (n = 9) or right-subventral (n = 6), rarely left-ventrosublateral (n = 1) or left-subventral (n = 1). Handedness of vulva position does not correspond with handedness of ovaries. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Supplements absent. Rectum 1.0 – 1.6 anal body diameters long; surrounded by three gland-like cells at intestinerectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFA8FFABFF4E09E3F86FDD17.taxon	diagnosis	Diagnosis (supplemented with literature data). Leptolaimus danicus is particularly characterised by the 516 – 609 µm long body; truncate-conoid labial region continuous with body contour; cephalic setae 1.5 – 3.0 µm long; amphid located 8.5 – 12.0 µm from anterior end; first body pore located 28.0 – 43.0 µm from anterior end; lateral field originating 34.0 – 58.0 µm from anterior end; female without supplements, vagina with triangular pars refringens, vulva usually right-ventrosublateral or right-subventral; male with 5 (4 – 6) tubular and 6 (6 – 7) alveolar supplements, tubular supplements straight with expanded dentate tips, alveolar supplements with sclerotized ring; spicules arcuate and 21.5 – 24.0 µm long.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFA8FFABFF4E09E3F86FDD17.taxon	discussion	Remarks. Current material completely agrees with the single known type specimen in general morphology, measurements, number and shape of tubular and alveolar supplements, shape of spicules and gubernaculum.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFB7FFAFFF4E0EE0FFC2DC2A.taxon	description	(Figs 6, 7 A – B; Table 5)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFB7FFAFFF4E0EE0FFC2DC2A.taxon	materials_examined	Type material. Holotype male (slide # Type- 8454) and three male and four female paratypes (slides # Type- 8455 - Type- 8456) deposited in the invertebrate type collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Type locality. Mud from 30 – 39 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 13 '', E 11 ° 27 ' 31 ''), 21 August 2010, legit M. Clément (four males and four females).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFB7FFAFFF4E0EE0FFC2DC2A.taxon	etymology	Etymology. The specific epithet " secundus " is translated as " the second " and refers to the sequential number of the new species described in this publication.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFB7FFAFFF4E0EE0FFC2DC2A.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; straight or ventrally curved upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 1.1 – 1.3 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 1.0 – 1.5 µm wide at mid-body; originating at level of stoma (anterior to the first body pore) and extending posteriorly to distal part of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually four pairs of body pores are present along pharyngeal region; several body pores scattered over rest of the body. Anteriormost body pore located at level of stoma base or procorpus. Labial region rounded, continuous with body contour, lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla setiform, equal to 30 – 50 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located anterior to middle of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system obscure. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (longer and more curved ventrad in male), elongate-conoid, gradually narrowing distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Four short setae emerging through first, second, third and fourth body pores. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate subcylindrical calamus and ovoid manubrium. Gubernaculum plate-like, with weak dorsocaudal apophysis. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip; single midventral tubular supplement; 9 – 15 alveolar supplements. Tubular supplement weakly arcuate in shape, with bluntly rounded tip, 42 – 47 µm anterior to cloaca, anterior to spicules. Alveolar supplements with thin sclerotized lining. Anteriormost alveolar supplement 147 – 153 µm from anterior end, at level of anterior part of intestine. Sublateral precloacal and caudal sensilla present: two (one pair) precloacal setae at level of cloaca and usually eight (four pairs) caudal setae arranged in two subventral and two subdorsal pairs. One subventral pair of papilliform sensilla located at the bases of the second (from cloaca) pair of caudal setae. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 72 – 90 µm long (equal to 11.3 – 13.9 % of total body length), located on right-hand side of intestine (n = 4), posterior genital branch 62 – 83 µm long (equal to 10.5 – 12.9 % of total body length), located on left-hand side of intestine (n = 4). Oviduct a narrow tube. Two offset, oval, sac-like spermathecae located on each (right and left) side of each (anterior and posterior) gonoduct. Spermathecae often filled with oval spermatozoa. Uterus a wide and short tube. Vagina straight, 0.3 – 0.4 times vulval body diameters long; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae absent. Vulva midventral. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Supplements absent. Rectum 1.3 – 2.6 anal body diameters long; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFB7FFAFFF4E0EE0FFC2DC2A.taxon	diagnosis	Diagnosis. Leptolaimus secundus sp. n. is particularly characterised by the 576 – 645 µm long body; rounded labial region continuous with body contour; cephalic setae 2.0 µm long; amphid located 6.5 – 7.0 µm from anterior end; first body pore located 23.0 – 28.5 µm from anterior end; lateral field originating 18.0 – 23.0 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male with single tubular and 9 – 15 alveolar supplements, tubular supplement weakly arcuate with blunt tips, alveolar supplements with sclerotized lining; spicules arcuate and 23.0 – 26.5 µm long. Relationships. The new species belongs to a group of species having both tubular and alveolar supplements in males. Leptolaimus secundus sp. n. differs from all known species in this group besides Leptolaimus donsi (Allgén, 1947) comb. n. in having just one tubular supplement. Although, males of L. donsi usually have two tubular supplements, we also found two aberrant specimens with just single tubular supplement (see below). The new species can however be easily differentiated from L. donsi in the shape (amphid without thick sclerotized rim vs. with sclerotized rim in L. donsi) and location of the amphid (6.5 – 7.0 µm from anterior end vs. 2.0 – 5.0 µm from anterior end in L. donsi), position of the anteriormost body pore (23.0 – 28.5 µm from anterior end vs. 11.5 – 14.0 µm from anterior end in L. donsi), position of the anterior end of lateral field (18.0 – 23.0 µm from anterior end vs. 8.0 – 13.0 µm from anterior end in L. donsi), orientation of vulva (ventral vs. right-ventrosublateral) and absence of pars refringens vaginae (vs. present in L. donsi). The only other known species of Leptolaimus having single tubular supplement is L. ditlevseni (Steiner, 1916) De Coninck, 1965. The new species differs from L. ditlevseni in having alveolar supplements (vs. absent in L. ditlevseni), length of spicules (23 – 27 µm vs. 11.5 µm in L. ditlevseni), and presence of gubernaculum (vs. absent in L. ditlevseni).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFB3FFA3FF4E0FFBFEDFD88B.taxon	description	(Figs 8, 9, 10 A – C; Table 6)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFB3FFA3FF4E0FFBFEDFD88B.taxon	materials_examined	Type material. Lectotype female (slide # Type- 3620) from the collection of C. Allgén. Additional material. 11 males and 21 females (slides # 129938 – 129949) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Type locality. North Atlantic Ocean, Trondheimsfjord, off Storfosen island, Norway (N 63 ° 39.5 ', E 9 ° 24 ’) (Allgén, 1947) Additional localities. Sandy sediment from 5 – 17 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 09 '', E 11 ° 27 ' 51 ''), 21 August 2010, legit M. Clément (one male); mud from 30 – 39 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 13 '', E 11 ° 27 ' 31 ''), 21 August 2010, legit M. Clément (one male and one female); sand and shells from 15 – 22 m deep, Bonden island in Skagerrak off the west coast of Sweden (N 58 12 ' 37 '', E 11 18 ' 53 ''), 09 August 2011, legit O. Holovachov (one male and four females); gravel, mud and algae from 30 – 70 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 14 '', E 11 ° 05 ' 00 ''), 09 August 2011, legit O. Holovachov (five males and eight females); muddy sand from 25 – 50 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 20 '', E 11 ° 09 ' 26 ''), 09 August 2011, legit O. Holovachov (one female); coarse sediment with algae from 45 – 55 m deep, Skagerrak off the west coast of Sweden (N 58 ° 17 ' 32 '', E 11 ° 11 ' 24 ''), 09 August 2011, legit O. Holovachov (three males and seven females).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFB3FFA3FF4E0FFBFEDFD88B.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; straight or ventrally curved upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 1.5 – 2.4 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 1.5 – 3.5 µm wide at mid-body; originating at level of posterior edge of amphid (at level with first body pore) and extending posteriorly to posterior third of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually six pairs of body pores are present along pharyngeal region; numerous body pores scattered over rest of the body. Anteriormost body pore located at posterior edge of amphid, at level of anterior part of stoma. Labial region truncated, continuous with body contour, lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla setiform, equal to 40 – 60 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located close to cephalic setae bases, at level of anterior third of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretoryexcretory system present; excretory pore located posterior to nerve ring. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (more curved ventrad in male), elongate-conoid, gradually narrowing distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Two pairs of short setae emerging through second and fourth pairs of body pores. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate subcylindrical calamus and ovoid manubrium. Gubernaculum plate-like, with dorsal apophysis. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, two midventral tubular supplements extending for 89 – 100 µm from cloaca towards anterior end; 9 – 14 alveolar supplements. Tubular supplements weakly arcuate in shape, with bluntly rounded tips. Posteriormost tubular supplement 45 – 53 µm anterior to cloaca, anterior to spicules. Alveolar supplements without inner sclerotized ring. Anteriormost alveolar supplement 158 – 185 µm from anterior end, at level of anterior part of intestine. Sublateral precloacal and caudal sensilla present: two (one pair) precloacal setae at level of cloaca and usually six (three pairs) caudal setae arranged in one subventral and two subdorsal pairs. One subventral pair of papilliform sensilla located at the bases of the second (from cloaca) pair of caudal setae. Aberrant male (Fig. 10 C). Similar to typical males except for the smaller body size and the following features. One midventral tubular supplement extending for 40 – 43 µm from cloaca towards anterior end; 13 – 14 alveolar supplements. Anteriormost alveolar supplement 133 – 152 µm from anterior end, at level of anterior part of intestine. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 103 – 135 µm long (equal to 10.5 – 15.7 % of total body length), located on right-hand side of intestine (n = 10), posterior genital branch 86 – 128 µm long (equal to 9.4 – 12.6 % of total body length), located on left-hand side (n = 8) or right-hand side (n = 2) of intestine. Oviduct a narrow tube. Two offset, oval, sac-like spermathecae located on each (right and left) side of each (anterior and posterior) gonoduct. Spermathecae filled with oval spermatozoa. Uterus a wide and long tube. Vagina straight, 0.2 – 0.3 times vulval body diameters long; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae present, bacilliform. Vulva rightventrosublateral. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Supplements absent. Rectum 1.1 – 2.4 anal body diameters long; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFB3FFA3FF4E0FFBFEDFD88B.taxon	diagnosis	Diagnosis (including data for lectotype, but excluding aberrant male specimens). Leptolaimus donsi is particularly characterised by the 776 – 1103 µm long body; truncated labial region continuous with body contour; cephalic setae 4.0 – 6.0 µm long; amphid located 2.0 – 5.0 µm from anterior end; first body pore located 11.5 – 14.0 µm from anterior end; lateral field originating 8.0 – 13.0 µm from anterior end; female without supplements, vagina with bacilliform pars refringens, vulva right-ventrosublateral; male with two tubular and 9 – 14 alveolar supplements, tubular supplements weakly arcuate with blunt tips, alveolar supplements without sclerotized inner ring; spicules arcuate and 30.0 – 33.5 µm long.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFB3FFA3FF4E0FFBFEDFD88B.taxon	discussion	Remarks. Current material agrees well with the type specimen in general morphology, measurements, shape of amphids, position of the first body pore and anterior end of lateral field, presence of pars refringens vaginae and right-ventrosublateral position of vulva. Two males with single tubular supplement found in Gullmarn Fjord are smaller in size than males with two tubular supplements from Skagerrak, but there are no significant morphological or morphometrical differences to justify considering them different species.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFBFFFA6FF4E0A5BFE44DA12.taxon	description	(Figs 10 D, 11; Table 7)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFBFFFA6FF4E0A5BFE44DA12.taxon	materials_examined	Type material. Holotype male (slide # Type- 8457) and one male paratype (slide # Type- 8458) deposited in the invertebrate type collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Type locality. Mud from 30 – 39 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 13 '', E 11 ° 27 ' 31 ''), 21 August 2010, legit M. Clément (two males).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFBFFFA6FF4E0A5BFE44DA12.taxon	etymology	Etymology. The specific epithet " tertius " is translated as " the third " and refers to the sequential number of the new species described in this publication.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFBFFFA6FF4E0A5BFE44DA12.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; straight or ventrally curved upon fixation, strongly curved ventrad in posterior part in males. Cuticle annulated; annuli 1.5 – 1.6 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures); originating at level of stoma base (posterior to first body pore) and extending posteriorly to posterior third of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; seven pairs of body pores are present along pharyngeal region, and one at level of cardia; numerous body pores scattered over rest of the body. Anteriormost body pore located at level of posterior 1 / 5 th of stoma. Labial region rounded, continuous with body contour, lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla setiform, equal to 30 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located anterior to middle of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system indistinct. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail conoid, gradually narrowing distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Two pairs of short setae emerging through third and fifth pairs of body pores. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate subcylindrical calamus and ovoid manubrium. Gubernaculum plate-like, with dorsal apophysis. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, four evenly spaced midventral tubular supplements extending for 118 – 131 µm from cloaca towards anterior end; 7 – 10 alveolar supplements. Tubular supplements weakly arcuate in shape, with bluntly rounded tips. Posteriormost tubular supplement 31 – 34 µm anterior to cloaca, anterior to spicules. Alveolar supplements with prominent inner sclerotized ring. Anteriormost alveolar supplement 160 – 172 µm from anterior end, at level of anterior part of intestine. Sublateral precloacal and caudal sensilla present: two (one pair) precloacal setae at level of cloaca and ten (five pairs) caudal setae arranged in three subventral and one subdorsal pairs. Female. Not found.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFBFFFA6FF4E0A5BFE44DA12.taxon	diagnosis	Diagnosis. Leptolaimus tertius sp. n. is particularly characterised by the 576 – 579 µm long body; rounded labial region continuous with body contour; cephalic setae 2 µm long; amphid located 4 – 5 µm from anterior end; first body pore located 21.0 – 23.5 µm from anterior end; lateral field originating 26 – 29 µm from anterior end; male with four tubular and 7 – 10 alveolar supplements, tubular supplements weakly arcuate with blunt tips, alveolar supplements with sclerotized inner ring; spicules arcuate and 25 – 26 µm long. Relationships. Leptolaimus tertius sp. n. is particularly characterised by the very anterior position of amphid and in this respect closely resembles L. donsi, from which it differs in having shorter body (576 – 579 vs. 776 – 1103 in L. donsi), more posterior position of the first body pore (21 – 24 µm vs. 11 – 14 µm in L. donsi), shorter spicules (25 – 26 µm vs. 30 – 34 µm in L. donsi), number of tubular supplements (4 vs. 2 in L. donsi). It should also be compared with L. mixtus and L. danicus, males of which have (or may have) four tubular supplements and a number of alveolar supplements. L. danicus has alveolar supplements with distinct sclerotized tube, that is absent in L. tertius sp. n. Moreover, the new species differs from L. danicus in the shape of tubules (with blunt tips vs. with dentate tips in L. danicus), position of the amphid (4 – 5 µm vs. 8 – 12 µm in L. danicus), first body pore (21 – 24 µm vs. 28 – 43 µm in L. danicus) and anterior end of the lateral field (26 – 29 µm vs. 34 – 58 µm in L. danicus). From L. mixtus the new species differs in the number of alveolar supplements (7 – 10 vs. 2 – 3 in L. mixtus) reaching anterior part of intestine (vs. reaching midbody level in L. mixtus).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFBAFFA5FF4E09E3FE66DD7D.taxon	description	(Figs 7 C – D, 12; Table 8)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFBAFFA5FF4E09E3FE66DD7D.taxon	materials_examined	Material examined. 47 males and 42 females (slides # 129950 – 129961) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Habitat and locality. Shells and sand from 15 – 22 m deep, Skagerrak off the west coast of Sweden (N 58 ° 12 ' 37 '', E 11 ° 18 ' 53 ''), 09 August 2011, legit O. Holovachov (four males and 15 females); muddy sediment from 53 m deep, Skagerrak off the west coast of Sweden (N 58 ° 20 ' 06 '', E 11 ° 09 ' 24 ''), 09 August 2011, legit O. Holovachov (two males); gravel, mud and algae from 30 – 70 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 14 '', E 11 ° 05 ' 00 ''), 09 August 2011, legit O. Holovachov (10 males and nine females); algae from 20 – 40 m deep, Skagerrak off the west coast of Sweden (N 58 ° 21 ' 49 '', E 11 ° 04 ' 42 ''), 09 August 2011, legit O. Holovachov (three males and two females); coarse gravel from 30 – 50 m deep, Skagerrak off the west coast of Sweden (N 58 ° 17 ' 58 '', E 11 ° 10 ' 05 ''), 09 August 2011, legit O. Holovachov (three males and one female); coarse sediment with algae from 45 – 55 m deep, Skagerrak off the west coast of Sweden (N 58 ° 17 ' 32 '', E 11 ° 11 ' 24 ''), 09 August 2011, legit O. Holovachov (25 males and 15 females).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFBAFFA5FF4E09E3FE66DD7D.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; straight or ventrally curved upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 1.7 – 2.1 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 1.0 – 1.5 µm wide at mid-body; originating at level of procorpus (anterior to or at level with first body pore) and extending posteriorly to middle of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually four pairs of body pores are present along pharyngeal region; several body pores scattered over rest of the body. Anteriormost body pore located at level of procorpus. Labial region rounded, continuous with body contour, lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla setiform, equal to 40 – 70 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located at level of anterior 2 / 5 th of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system obscure. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (more curved ventrad in male), elongate-conoid, gradually narrowing distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Four short setae emerging through first, second, third and fourth pairs of body pores. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate subcylindrical calamus and ovoid manubrium. Gubernaculum plate-like, with dorsal apophysis bending anteriorly. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, four evenly spaced midventral tubular supplements extending for 138 – 176 µm from cloaca towards anterior end; two alveolar supplements. Out of 30 examined males, only two males had three alveolar supplements instead of the usual two. Tubular supplements almost straight, with blunt expanded tips. Posteriormost tubular supplement 28 – 41 µm anterior to cloaca, anterior to spicules. Alveolar supplements with inner sclerotized ring. Anteriormost alveolar supplement 341 – 407 µm from anterior end, at level of posterior part of intestine. Sublateral precloacal and caudal sensilla present: two (one pair) precloacal setae at level of cloaca and usually eight (four pairs) caudal setae arranged in two subventral and two subdorsal pairs. One subventral pair of papilliform sensilla located at the bases of the second (from cloaca) pair of caudal setae. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 76 – 138 µm long (equal to 10.6 – 17.7 % of total body length), located on right-hand side of intestine (n = 5), posterior genital branch 79 – 131 µm long (equal to 9.4 – 16.5 % of total body length), located on left-hand side of intestine (n = 5). Oviduct a narrow tube. Two offset, oval, sac-like spermathecae located on each (right and left) side of each (anterior and posterior) gonoduct. Spermathecae often filled with oval spermatozoa. Uterus a wide and short tube. Vagina straight; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae absent. Vulva usually left-ventrosublateral (n = 6), less commonly right-ventrosublateral (n = 2). Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Supplements absent. Rectum 1.6 – 2.1 anal body diameters long; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFBAFFA5FF4E09E3FE66DD7D.taxon	diagnosis	Diagnosis (supplemented with literature data). Leptolaimus mixtus is particularly characterised by the 659 – 845 µm long body; rounded labial region continuous with body contour; cephalic setae 2.0 – 5.0 µm long; amphid located 6.0 – 9.0 µm from anterior end; first body pore located 24.0 – 36.0 µm from anterior end; lateral field originating 20.0 – 32.0 µm from anterior end; female without supplements, vagina without pars refringens, vulva left- or right-ventrosublateral; male with four tubular and two (rarely three) alveolar supplements, tubular supplements almost straight with blunt expanded tips, alveolar supplements with sclerotized inner ring; spicules arcuate and 22.0 – 30.0 µm long.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFBAFFA5FF4E09E3FE66DD7D.taxon	discussion	Remarks. Current material agrees well with the type specimens in general morphology, measurements, number and shape of supplements, shape of spicules and gubernaculum. Specimens from Skagerrak are also very similar to L. mixtus from Oosterschelde, the Netherlands (Holovachov & Boström, 2004), with only difference being details of the vagina, which is described as having pars refringens. Male specimen from Oosterschelde has three alveolar supplements, which is not common in males from Skagerrak – only two out of 30 examined males from Skagerrak had three alveolar supplements, instead of two.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFB9FF98FF4E0EC4FCB6DFE7.taxon	description	(Figs 7 E, 13; Table 9)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFB9FF98FF4E0EC4FCB6DFE7.taxon	materials_examined	Type material. Holotype male (slide # Type- 8459) deposited in the invertebrate type collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Additional material. Three males (slides # 129936, 129962 – 129963) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Type locality. Coarse gravel from 30 – 50 m deep, Skagerrak off the west coast of Sweden (N 58 ° 17 ' 58 '', E 11 ° 10 ' 05 ''), 09 August 2011, legit O. Holovachov (one male). Additional localities. Coarse sediment with algae from 45 – 55 m deep, Skagerrak off the west coast of Sweden (N 58 ° 17 ' 32 '', E 11 ° 11 ' 24 ''), 09 August 2011, legit O. Holovachov (two males); muddy sediment from 55 – 70 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 19 '', E 11 ° 04 ' 55 ''), 09 August 2011, legit O. Holovachov (one male).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFB9FF98FF4E0EC4FCB6DFE7.taxon	etymology	Etymology. The specific epithet " quartus " is translated as " the fourth " and refers to the sequential number of the new species described in this publication.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFB9FF98FF4E0EC4FCB6DFE7.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; strongly curved ventrad in posterior part. Cuticle annulated; annuli 1.4 – 2.0 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 1.0 µm wide at mid-body; originating at level of stoma base or procorpus (anterior to first body pore) and extending posteriorly to middle of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually four pairs of body pores are present along pharyngeal region; several body pores scattered over rest of the body. Anteriormost body pore located at level of procorpus. Labial region rounded, continuous with body contour, lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla setiform, equal to 50 – 80 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located at level of anterior 2 / 5 th of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretoryexcretory system obscure. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail elongate-conoid, gradually narrowing distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Three or four long setae emerging through first, second, third and often fourth pairs of body pores. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate subcylindrical calamus and ovoid manubrium. Gubernaculum plate-like, with dorsal apophysis bending anteriad. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, three evenly spaced midventral tubular supplements extending for 95 – 119 µm from cloaca towards anterior end; eight – nine alveolar supplements. Tubular supplements almost straight, with blunt expanded tips. Posteriormost tubular supplement 28 – 36 µm anterior to cloaca, anterior to spicules. Alveolar supplements with inner sclerotized ring. Anteriormost alveolar supplement 142 – 159 µm from anterior end, at level of anterior part of intestine. Sublateral precloacal and caudal sensilla present: two (one pair) precloacal setae at level of cloaca and usually eight (four pairs) caudal setae arranged in two subventral and two subdorsal pairs. One subventral pair of papilliform sensilla located at the bases of the second (from cloaca) pair of caudal setae. Female. Not found.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFB9FF98FF4E0EC4FCB6DFE7.taxon	diagnosis	Diagnosis. Leptolaimus quartus sp. n. is particularly characterised by the 597 – 686 mm long body; rounded labial region continuous with body contour; cephalic setae 2.0 – 3.5 µm long; amphid located 5.0 – 7.0 µm from anterior end; first body pore located 23.5 – 27.0 µm from anterior end; lateral field originating 19.0 – 27.0 µm from anterior end; male with three tubular and 8 – 9 alveolar supplements, tubular supplements straight with blunt expanded tips, alveolar supplements with sclerotized inner ring; spicules arcuate and 23.0 – 25.0 µm long. Relationships. In general morphology and measurements, the new species is most closely related to L. mixtus and L. secundus sp. n. Leptolaimus quartus sp. n. differs from both these species in number of tubular and alveolar supplements (3 tubular and 8 – 9 alveolar vs. 1 tubular and 9 – 15 alveolar in L. secundus sp. n. vs. 4 tubular and 2 – 3 alveolar in L. mixtus).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF84FF9FFF4E0CB0FCB5D9A2.taxon	description	(Figs 14 – 16; Table 10)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF84FF9FFF4E0CB0FCB5D9A2.taxon	materials_examined	Material examined. 18 males and 29 females (slides # 130540 – 130546) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Habitat and locality. Shells and sand from 15 – 22 m deep, Skagerrak off the west coast of Sweden (N 58 ° 12 ' 37 '', E 11 ° 18 ' 53 ''), 09 August 2011, legit O. Holovachov (18 males and 29 females).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF84FF9FFF4E0CB0FCB5D9A2.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; ventrally curved upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 3.1 – 3.9 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 1.5 – 2.0 µm wide at mid-body; originating at level of metacorpus (posterior to first body pore) and extending posteriorly to middle or posterior third of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; 7 – 11 pairs of body pores are present along pharyngeal region; numerous body pores scattered over rest of the body. Anteriormost body pore located at level of procorpus. One pair of dorsosublateral setae are located a short distance posterior to nerve ring, similar to Stephanolaimus elegans Ditlevsen, 1918 as described by Holovachov & Boström (2004). Labial region truncate, continuous with body contour, lips fused. Inner labial sensilla indistinct. Outer labial sensilla papilliform, located on the anterior surface of lips. Cephalic sensilla setiform, equal to 40 – 70 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located at level of anterior 1 / 3 rd of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system present; excretory pore located posterior to nerve ring, just in front of the basal bulb. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia conoid, its posterior part embedded in intestine. Tail similar in shape in both sexes (more curved ventrad in male), conoid, gradually narrowing distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. No additional setiform sensilla along the pharyngeal region. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate cylindrical calamus and ovoid manubrium. Gubernaculum plate-like, with paired dorsal apophyses. Accessory apparatus composed of one midventral precloacal setiform sensillum located on anterior cloacal lip, one midventral setiform sensilla located midway between cloaca and posteriormost supplement, 5 – 9 evenly spaced midventral tubular supplements extending for 291 – 405 µm from cloaca towards anterior end; 2 – 5 midventral tubular supplements along the pharyngeal region; alveolar supplements absent. Tubular supplements located along the pharyngeal region are hook-like in shape, tubular supplements located along the posterior body region are weakly sigmoid or weakly arcuate in shape, with anchor-like tips. Posteriormost tubular supplement 64 – 71 µm anterior to cloaca, anterior to spicules. Sublateral precloacal and caudal sensilla present: four (one ventrosublateral and one dorsosublateral pair) precloacal setae at level of spicules and 6 – 8 caudal setae arranged in 3 – 4 subventral pairs. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 200 – 314 µm long (equal to 11.1 – 19.4 % of total body length), located on right-hand side of intestine (n = 9) or left-hand side of intestine (n = 2), posterior genital branch 214 – 329 µm long (equal to 11.9 – 20.0 % of total body length), located on left-hand side of intestine (n = 11). Oviduct a narrow tube. One offset, oval, sac-like spermatheca located on right side of anterior gonoduct and one on left side of posterior gonoduct. Spermathecae often filled with oval spermatozoa. Uterus a wide and long tube, often filled with spermatozoa as well. Vagina straight, 0.3 – 0.4 times vulval body diameters long; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae absent. Vulva midventral. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Two to four tubular supplements present: one to three anterior located along the pharyngeal region, and one posterior located in front of anus, 9 – 13 µm anterior to anal opening. Rectum 1.0 – 1.5 anal body diameters long; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF84FF9FFF4E0CB0FCB5D9A2.taxon	diagnosis	Diagnosis (supplemented with literature data). Leptolaimus pellucidus is particularly characterised by the 1460 – 1935 µm long body; truncated labial region continuous with body contour; cephalic setae 3.5 – 8.0 µm long; amphid located 8.5 – 11.0 µm from anterior end; first body pore located 38.0 – 51.0 µm from anterior end; lateral field originating 71.5 – 92.0 µm from anterior end; female with 1 – 3 tubular supplements along pharyngeal region and one tubular supplement in front of anus, vagina without pars refringens, vulva midventral; male with 2 – 5 tubular supplements along pharyngeal region and 5 – 9 tubular supplements in front of cloaca, without alveolar supplements, tubular supplements hook-like or weakly arcuate in shape with anchor-like tips; spicules arcuate and 47.0 – 70.0 µm long.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF84FF9FFF4E0CB0FCB5D9A2.taxon	discussion	Remarks. Current specimens agree well with the type specimens in general morphology, measurements, number, arrangement and shape of tubular supplements, presence of two midventral precloacal setiform sensilla in male, and shape of spicules and gubernaculum. The only difference is somewhat longer spicules in our specimens (55.0 – 68.0 µm vs. 47.0 – 52.0 µm in the original description). A single male specimen described by Gerlach (1953 a) also agrees well with the current material in both morphology and morphometrics, with the exception of longer cephalic setae (8 µm vs. 3.5 – 5.0 µm in current specimens), and slightly longer spicules (70.0 µm vs. 55.0 – 68.0 µm in current specimens).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF80FF90FF4E0B64F97EDAA2.taxon	description	(Figs 17, 18 E – F; Table 11)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF80FF90FF4E0B64F97EDAA2.taxon	materials_examined	Material examined. 29 males and 39 females (slides # 130457 – 130560) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Habitat and locality. Mud from 30 – 39 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 13 '', E 11 ° 27 ' 31 ''), 21 August 2010, legit M. Clément (three females); soft mud from 30 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 25 '', E 11 ° 27 ' 30 ''), 11 August 2011, legit O. Holovachov (three males and five females); soft mud from 44 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 37 '', E 11 ° 27 ' 43 ''), 11 August 2011, legit O. Holovachov (nine males and 12 females); muddy sediment from 53 m deep, Skagerrak off the west coast of Sweden (N 58 ° 20 ' 06 '', E 11 ° 09 ' 24 ''), 09 August 2011, legit O. Holovachov (three females); gravel, mud and algae from 30 – 70 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 14 '', E 11 ° 05 ' 00 ''), 09 August 2011, legit O. Holovachov (eight males and nine females); muddy sand from 25 – 50 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 20 '', E 11 ° 09 ' 26 ''), 09 August 2011, legit O. Holovachov (five males and five females); muddy sediment from 55 – 70 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 19 '', E 11 ° 04 ' 55 ''), 09 August 2011, legit O. Holovachov (three males and two females).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF80FF90FF4E0B64F97EDAA2.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; straight or ventrally curved upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 1.6 – 2.1 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 1.5 – 3.0 µm wide at mid-body; originating at level of metacorpus (posterior to first body pore) and extending posteriorly to middle of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually three pairs of body pores are present along pharyngeal region; several body pores scattered over rest of the body. Anteriormost body pore located at level of procorpus. Labial region rounded, continuous with body contour, lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla setiform, equal to 30 – 50 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located at level of middle of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system indistinct. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (shorter and more curved ventrad in male), elongate-conoid, subcylindrical distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Setae absent. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate subcylindrical calamus and ovoid manubrium. Gubernaculum plate-like, with dorsocaudal apophysis. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, three to four unevenly spaced midventral tubular supplements extending for 70 – 111 µm from cloaca towards anterior end; alveolar supplements absent. Tubular supplements weakly arcuate with claw-like tips pointing towards posterior end, the distance between second posteriormost and third posteriormost supplement is somewhat larger than the distance between first posteriormost and second posteriormost supplements. Posteriormost tubular supplement 17 – 25 µm anterior to cloaca, anterior to spicules. Sublateral precloacal and caudal sensilla present: two (one pair) precloacal setae at level of cloaca and usually six (three pairs) caudal setae arranged in two subventral and one subdorsal pairs. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 55 – 97 µm long (equal to 8.8 – 16.0 % of total body length), located on right-hand side of intestine (n = 8), posterior genital branch 55 – 90 µm long (equal to 9.6 – 14.9 % of total body length), located on left-hand side of intestine (n = 8). Oviduct a narrow tube. One offset, oval, sac-like spermatheca located on right side of anterior gonoduct and one on left side of posterior gonoduct. Spermathecae often filled with oval spermatozoa. Uterus a wide and short tube. Vagina straight, 0.2 – 0.3 times vulval body diameters long; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae absent. Vulva midventral. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Usually one tubular supplement located in front of anus, 21.5 – 33.0 µm anterior to anal opening; one female had two tubular supplements and one female had none. Rectum 1.1 – 1.6 anal body diameters long; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF80FF90FF4E0B64F97EDAA2.taxon	diagnosis	Diagnosis (supplemented with literature data). Leptolaimus venustus is particularly characterised by the 541 – 669 µm long body; rounded labial region continuous with body contour; cephalic setae 1.0 – 2.0 µm long; amphid located 8.5 – 11.5 µm from anterior end; first body pore located 27.0 – 36.0 µm from anterior end; lateral field originating 35.0 – 53.0 µm from anterior end; female with usually one preanal supplement, vagina without pars refringens, vulva midventral; male with three to four tubular and without alveolar supplements, tubular supplements weakly arcuate with claw-like tips pointing towards posterior end; spicules arcuate and 18.5 – 22.0 µm long.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF80FF90FF4E0B64F97EDAA2.taxon	discussion	Remarks. Current specimens agree well with the type specimen in general morphology, measurements and shape of amphids, the only difference being the reported length of spicules in the original description – 15 µm vs. 20 – 22 µm in recent specimens. When measured from the original illustrations, the actual spicule length is 18.5 µm, which would be considered as normal range for geographically distinct populations.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF8CFF97FF4E0873F974DD72.taxon	description	(Fig. 18 C – D, 19; Table 12)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF8CFF97FF4E0873F974DD72.taxon	materials_examined	Material examined. One male and two females (slides # 130564 – 130566) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Habitat and locality. Soft mud from 30 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 25 '', E 11 ° 27 ' 30 ''), 11 August 2011, legit O. Holovachov (one male and one female), soft mud from 44 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 37 '', E 11 ° 27 ' 43 ''), 11 August 2011, legit O. Holovachov (one female).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF8CFF97FF4E0873F974DD72.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; straight or ventrally curved upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 2.0 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 1.5 µm wide at mid-body; originating at level of metacorpus (posterior to first body pore) and extending posteriorly to middle of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually three pairs of body pores are present along pharyngeal region; numerous body pores scattered over rest of the body. Anteriormost body pore located at level of stoma base. Labial region rounded, continuous with body contour, lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla setiform, equal to 40 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea rounded, located at level of middle of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system indistinct. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (shorter and more curved ventrad in male), elongate-conoid, gradually narrowing distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Three pairs of long setae emerging through first, second and third pairs of body pores. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate subcylindrical calamus and conoid manubrium. Gubernaculum plate-like, with dorsal apophysis. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, five unevenly spaced midventral tubular supplements extending for 414 µm from cloaca towards anterior end; alveolar supplements absent. Tubular supplements weakly arcuate, almost straight in shape, with anchor-like tips; one supplement located just posterior to cardia, and four supplements along the posterior body part unevenly spaced, the distance between third posteriormost and fourth posteriormost supplement is twice as big as the distance between second posteriormost and third posteriormost supplements. Posteriormost tubular supplement 26.0 µm anterior to cloaca, anterior to spicules. Sublateral precloacal and caudal sensilla present: two (one pair) precloacal setae at level of cloaca and at least six (three pairs) caudal setae arranged in two subventral and one subdorsal pairs. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 68 – 70 µm long (equal to 9.7 – 10.3 % of total body length), located on right-hand side of intestine (n = 2), posterior genital branch 75 µm long (equal to 10.7 – 11.0 % of total body length), located on left-hand side of intestine (n = 2). Oviduct a narrow tube. One offset, oval, sac-like spermatheca located on right side of anterior gonoduct and one on left side of posterior gonoduct. Spermathecae often filled with oval spermatozoa. Uterus a wide tube. Vagina straight, 0.3 times vulval body diameters long; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae present, drop-shaped. Vulva midventral. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Two tubular supplements present: one anterior located along the anterior part of intestine, and one posterior located in front of anus, 24 – 28 µm anterior to anal opening. Rectum 1.3 anal body diameters long; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF8CFF97FF4E0873F974DD72.taxon	diagnosis	Diagnosis (supplemented with literature data). Leptolaimus lorenzeni is particularly characterised by the 621 – 735 µm long body; rounded labial region continuous with body contour; cephalic setae 1.5 – 4.0 µm long; amphid located 8.0 – 9.0 µm from anterior end; first body pore located 16.5 – 24.0 µm from anterior end; lateral field originating 46.0 – 47.0 µm from anterior end; female with two tubular supplements (one just posterior to cardia and one in front of anus), vagina with drop-shaped pars refringens, vulva midventral; male with five tubular and without alveolar supplements, tubular supplements weakly arcuate with anchor-like tips, one just posterior to cardia and four unevenly spaced in front of cloaca; spicules arcuate and 16.0 – 20.0 µm long.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF8CFF97FF4E0873F974DD72.taxon	discussion	Remarks. Current specimens agree well with the type specimens in general morphology, number and arrangement of tubular supplements both in females and males, etc., the only difference being length of spicules (20.0 µm in recent male vs. 16 µm in the male described by Lorenzen). Unfortunately, the description of this species by Lorenzen (1972 b) is not detailed enough to allow any further comparison.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF8BFF8AFF4E0EC3FC2CDDA7.taxon	description	(Fig. 18 A – B, 20; Table 13)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF8BFF8AFF4E0EC3FC2CDDA7.taxon	materials_examined	Type material. Holotype male (slide # Type- 8476) and nine female paratypes (slides # Type- 8476 - Type- 8477) deposited in the invertebrate type collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Additional material. Four males and 14 females (slides # 130567 – 130572) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Type locality. Muddy sediment from 55 – 70 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 19 '', E 11 ° 04 ' 55 ''), 09 August 2011, legit O. Holovachov (one male and nine females). Additional localities. Gravel, mud and algae from 30 – 70 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 14 '', E 11 ° 05 ' 00 ''), 09 August 2011, legit O. Holovachov (one male and three females); soft mud from 30 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 25 '', E 11 ° 27 ' 30 ''), 11 August 2011, legit O. Holovachov (one female); soft mud from 44 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 37 '', E 11 ° 27 ' 43 ''), 11 August 2011, legit O. Holovachov (three males and ten females).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF8BFF8AFF4E0EC3FC2CDDA7.taxon	etymology	Etymology. The specific epithet " quintus " is translated as " the fifth " and refers to the sequential number of the new species described in this publication.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF8BFF8AFF4E0EC3FC2CDDA7.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; straight or weakly ventrally curved upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 1.5 – 2.0 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 1.5 – 2.0 µm wide at mid-body; originating at level of procorpus (posterior to first body pore) and extending posteriorly to posterior third of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually three pairs of body pores are present along pharyngeal region; several body pores scattered over rest of the body. Anteriormost body pore located at level of procorpus. Labial region rounded, continuous with body contour, lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla setiform, equal to 30 – 50 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located at level of posterior third of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system present; excretory pore located posterior to nerve ring. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (more curved ventrad in male), elongateconoid, gradually narrowing distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Long setae emerging through all pairs of body pores throughout the body. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate subcylindrical calamus and ovoid manubrium. Gubernaculum plate-like, with dorsal apophysis. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, 8 – 10 midventral tubular supplements extending for 281 – 341 µm from cloaca towards anterior end, the gap between the posteriormost fourth (or fifth) and posteriormost fifth (or sixth) tubules is somewhat bigger than between the other tubules; alveolar supplements absent. Tubular supplements weakly arcuate with anchor-like tips. Posteriormost tubular supplement 24.0 – 30.0 µm anterior to cloaca, anterior to spicules. Sublateral precloacal and caudal sensilla present: two (one pair) precloacal setae at level of cloaca and usually eight (four pairs) caudal setae arranged in two subventral and two subdorsal pairs. One subventral pair of papilliform sensilla located at the bases of the second (from cloaca) pair of caudal setae. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 34 – 56 µm long (equal to 6.8 – 12.4 % of total body length), located on right-hand side of intestine (n = 9), posterior genital branch 37 – 54 µm long (equal to 7.6 – 11.9 % of total body length), located on left-hand side of intestine (n = 9). Oviduct a narrow tube. One offset, oval, sac-like spermatheca located on right side of anterior gonoduct and one on left side of posterior gonoduct. Spermathecae often filled with oval spermatozoa. Uterus a wide tube. Vagina straight, 0.3 times vulval body diameters long; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae absent. Vulva right-sublateral, recessed, often covered with distinct refractive copulatory plug. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Two tubular supplements present: one anterior located just posterior to cardia, 107 – 123 µm from anterior end, and one posterior located in front of anus, 21.5 – 28.5 µm anterior to anal opening. Rectum 0.9 – 1.6 anal body diameters long; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF8BFF8AFF4E0EC3FC2CDDA7.taxon	diagnosis	Diagnosis. Leptolaimus quintus sp. n. is particularly characterised by the 443 – 528 µm long body; rounded labial region continuous with body contour; cephalic setae 1.0 – 2.0 µm long; amphid located 7.0 – 10.0 µm from anterior end; first body pore located 18.0 – 28.5 µm from anterior end; lateral field originating 25.0 – 41.0 µm from anterior end; female with two tubular supplements (one just posterior to cardia and one in front of anus), vagina without pars refringens, vulva right-sublateral; male with 8 – 10 tubular and without alveolar supplements, tubular supplements weakly arcuate with anchor-like tips; spicules arcuate and 17.0 – 22.0 µm long. Relationships. The new species belongs to a group of species, females of which have tubular supplements along the pharyngeal region and in front of cloaca, e. g.: L. cangionensis (Gagarin & Nguyen Vu Thanh, 2007) comb. n., L. rivalis (Gagarin & Nguyen Vu Thanh, 2007) comb. n., L. lorenzeni, L. harpaga (Boucher & de Bovée, 1972) comb. n., L. pellucidus and L. sergeevae (Ürkmez & Brennan, 2013) comb. n.. Leptolaimus quintus sp. n. differs from L. cangionensis, L. rivalis, L. lorenzeni, L. harpaga and L. pellucidus in having males with 4 – 6 supplements in the anterior group arranged posterior to cardia (vs. either single supplement located posterior to cardia in L. cangionensis, L. rivalis, L. lorenzeni, L. harpaga or 1 – 3 supplements located along the pharyngeal region in L. pellucidus), and from L. sergeevae in having only two tubular supplements in females (vs. five in L. sergeevae).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF96FF8EFF4E0970FC08DD7D.taxon	description	(Figs 21, 22 A – B; Table 14)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF96FF8EFF4E0970FC08DD7D.taxon	materials_examined	Type material. Holotype male (slide # Type- 8479) and 15 male and 18 female paratypes (slides # Type- 8479 - Type- 8487) deposited in the invertebrate type collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Type locality. Mud from 30 – 39 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 13 '', E 11 ° 27 ' 31 ''), 21 August 2010, legit M. Clément (16 males and 18 females).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF96FF8EFF4E0970FC08DD7D.taxon	etymology	Etymology. The specific epithet " sextus " is translated as " the sixth " and refers to the sequential number of the new species described in this publication.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF96FF8EFF4E0970FC08DD7D.taxon	description	Description. Adult. Body fusiform, strongly tapering anteriorly in pharyngeal region and posteriorly on tail; ventrally curved or coiled upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 2.5 – 3.3 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 2.0 – 3.5 µm wide at mid-body; originating at level of posterior part of stoma (anterior to first body pore) and extending posteriorly to proximal part of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually five pairs of body pores are present along pharyngeal region, and one at level of cardia; numerous body pores scattered over rest of the body. Anteriormost body pore located at level of procorpus. Labial region truncate, offset from body contour, lips fused. Inner labial sensilla indistinct; outer labial sensilla large and papilliform, located on the outer surface of lips. Cephalic sensilla setiform, equal to 20 – 50 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located at level of anterior third of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system present; excretory pore located posterior to nerve ring. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (more curved ventrad in male), conoid, gradually narrowing distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Long setae emerging through first, second and fifth pairs of body pores. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate cylindrical calamus and ovoid manubrium. Gubernaculum plate-like, with double caudal apophyses. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, five (six in one specimen) evenly spaced midventral tubular supplements extending for 177 – 232 µm from cloaca towards anterior end; alveolar supplements absent. Tubular supplements weakly S-shaped, with bifid tips. Posteriormost tubular supplement 20.0 – 28.0 µm anterior to cloaca, at level of spicules. Sublateral precloacal and caudal sensilla present: two (one pair) precloacal setae at level of spicules and usually four (two pairs) caudal papillae arranged in two subventral pairs. Aberrant male. Similar to typical males except for the larger body size and presence of nine midventral tubular supplements extending for 281 µm from cloaca towards anterior end. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 69 – 129 µm long (equal to 10.3 – 18.3 % of total body length), located on right-hand side of intestine (n = 11), posterior genital branch 76 – 122 µm long (equal to 11.2 – 17.6 % of total body length), located on left-hand side of intestine (n = 11). Oviduct a narrow tube. Spermathecae obscure. Uterus a wide tube. Vagina straight, 0.3 times vulval body diameters long; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae absent. Vulva midventral. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Supplements absent. Rectum 1.6 – 2.2 anal body diameters long, often S-shaped in lateral view; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF96FF8EFF4E0970FC08DD7D.taxon	diagnosis	Diagnosis (single aberrant male excluded). Leptolaimus sextus sp. n. is particularly characterised by the 626 – 728 µm long body; truncated labial region offset from body contour; cephalic setae 1.5 – 2.0 µm long; amphid located 8.0 – 12.0 µm from anterior end; first body pore located 41.0 – 48.5 µm from anterior end; lateral field originating 28.0 – 41.0 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male with five (rarely six) tubular and without alveolar supplements, tubular supplements weakly Sshaped with bifid tips; spicules arcuate and 39.0 – 46.0 µm long. Relationships. Current specimens are similar to the type specimen of L. alatus Vitiello, 1971 in general morphology, shape of labial region, distinct papilliform cephalic setae, position of amphid, anterior body pore, lateral field, number and shape of tubular supplements, shape of gubernaculum. The major differences are body size (626 – 728 µm vs. 595 µm in L. alatus), length of spicules (39.0 – 46.0 µm vs. 26.0 µm in L. alatus), shape of supplements (with bifid tips vs. without in L. alatus). Unfortunately, the original description of L. alatus is not complete and insufficiently illustrated to allow any further comparisons. However, we found a population that we think belongs to L. alatus (see description below). L. sextus sp. n. differs from this population of L. alatus in larger body (626 – 728 µm vs. 376 – 518 µm in L. alatus) and other measurements, number and shape of tubular supplements (usually five and with bifid tips vs. usually seven and with blunt tips in L. alatus). In having bifid tips of tubular supplements, the new species shows similarities to L. gerlachi Murphy, 1966, L. praeclarus Timm, 1961 and L. vipriensis Gagarin & Nguyen Vu Thanh, 2005, but it can be easily distinguished from all three species by the shape of the labial region with distinct papilliform outer labial sensilla (vs. outer labial sensilla indistinct), among other characters. Leptolaimus limicolus Lorenzen, 1972 has similar number of supplements and shape of spicules, however it can be easily separated from L. sextus sp. n. in the shape of lip region and size of outer labial sensilla (indistinct vs. large distinct papilliform in L. sextus sp. n.) and asymmetrical spicules (vs. symmetrical in L. sextus sp. n.).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF92FF8DFF4E0EC3F972DF57.taxon	description	(Figs 22 C – D, 23; Table 15)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF92FF8DFF4E0EC3F972DF57.taxon	materials_examined	Material examined. Seven males and 22 females (slides # 130715 – 130722) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Habitat and locality. Mud from 30 – 39 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 13 '', E 11 ° 27 ' 31 ''), 21 August 2010, legit M. Clément (seven males and 20 females); soft mud from 44 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 37 '', E 11 ° 27 ' 43 ''), 11 August 2011, legit O. Holovachov (one female); gravel, mud and algae from 30 – 70 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 14 '', E 11 ° 05 ' 00 ''), 09 August 2011, legit O. Holovachov (one female).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF92FF8DFF4E0EC3F972DF57.taxon	description	Description. Adult. Body fusiform, strongly tapering anteriorly in pharyngeal region and posteriorly on tail; ventrally curved or coiled upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 1.6 – 2.2 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 1.5 – 2.0 µm wide at mid-body; originating at level of posterior part of stoma (anterior to first body pore) in males or at stoma base (close to first body pore) in females, and extending posteriorly to posterior third of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually five pairs of body pores are present along pharyngeal region; numerous body pores scattered over rest of the body. Anteriormost body pore located at level of stoma base. Labial region truncate, offset from body contour, lips fused. Inner labial sensilla indistinct; outer labial sensilla large and papilliform, located on the outer surface of lips. Cephalic sensilla setiform, equal to 30 – 50 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located at level of anterior third of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system present; excretory pore located posterior to nerve ring. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (more curved ventrad in male), conoid, gradually narrowing distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Long setae emerging through first, second and fifth pairs of body pores. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate subcylindrical calamus and ovoid manubrium. Gubernaculum plate-like, with dorsocaudal apophysis. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, six – eight evenly spaced midventral tubular supplements extending for 132 – 205 µm from cloaca towards anterior end; alveolar supplements absent. Tubular supplements weakly S-shaped, with blunt tips. Posteriormost tubular supplement 17.0 – 28.0 µm anterior to cloaca, at level of spicules. Sublateral precloacal and caudal sensilla present: two (one pair) precloacal setae at level of spicules and several caudal setae of which only one pair can be clearly seen in all specimens; remaining setae (if present) are indistinct due to filamentous debris covering distal parts of tails in all studied males. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 48 – 61 µm long (equal to 11.6 – 14.2 % of total body length), located on right-hand (n = 11) or left-hand (n = 3) side of intestine, posterior genital branch 56 – 88 µm long (equal to 13.416.9 % of total body length), located on left-hand (n = 11) or right-hand (n = 3) side of intestine. Oviduct a narrow tube. Spermathecae obscure. Uterus a wide tube. Vagina straight, 0.3 – 0.5 times vulval body diameters long; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae absent. Vulva midventral. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Supplements absent. Rectum 1.0 – 1.7 anal body diameters long, S-shaped in lateral view in some specimens; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF92FF8DFF4E0EC3F972DF57.taxon	diagnosis	Diagnosis (supplemented with literature data). Leptolaimus alatus is particularly characterised by the 376 – 595 µm long body; truncate labial region offset from body contour; cephalic setae 1.5 – 2.0 µm long; amphid located 6.0 – 10.0 µm from anterior end; first body pore located 26.0 – 37.0 µm from anterior end; lateral field originating 20.0 – 34.0 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male with six – eight tubular and without alveolar supplements, tubular supplements weakly S-shaped with blunt tips; spicules arcuate and 26.0 – 40.0 µm long.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF92FF8DFF4E0EC3F972DF57.taxon	discussion	Remarks. Current specimens are similar to the type and only specimen of L. alatus in general morphology, shape of labial region, size of outer labial sensilla, position of amphid, anterior body pore, lateral field, number and shape of tubular supplements, and shape of gubernaculum. The major differences are body size (376 – 518 µm vs. 595 µm in L. alatus) and length of spicules (31.0 – 40.0 µm vs. 26.0 µm in L. alatus).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF91FF81FF4E0C20FE4FDD82.taxon	description	(Figs 24, 25 A – B; Table 16)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF91FF81FF4E0C20FE4FDD82.taxon	materials_examined	Type material. Holotype male (slide # Type- 8488) and four male and eight female paratypes (slides # Type- 8488 - Type- 8492) deposited in the invertebrate type collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Additional material. One female (slide # 131244) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Type locality. Shells and sand from 15 – 22 m deep, Skagerrak off the west coast of Sweden (N 58 ° 12 ' 37 '', E 11 ° 18 ' 53 ''), 09 August 2011, legit O. Holovachov (five males and eight females). Additional localities. Coarse gravel from 30 – 50 m deep, Skagerrak off the west coast of Sweden (N 58 ° 17 ' 58 '', E 11 ° 10 ' 05 ''), 09 August 2011, legit O. Holovachov (one female);	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF91FF81FF4E0C20FE4FDD82.taxon	etymology	Etymology. The specific epithet " septimus " is translated as " the seventh " and refers to the sequential number of the new species described in this publication.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF91FF81FF4E0C20FE4FDD82.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; strongly ventrally curved or coiled upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 2.2 – 3.1 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 1.5 – 2.0 µm wide at mid-body; originating at level of posterior part of stoma or stoma base (anterior to first body pore) and extending posteriorly to middle of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually five pairs of body pores are present along pharyngeal region; numerous body pores scattered over rest of the body. Anteriormost body pore located at level of procorpus. Labial region truncate, offset from body contour, lips fused. Inner labial sensilla indistinct. Outer labial sensilla large and papilliform, located on the outer surface of lips. Cephalic sensilla setiform, equal to 50 – 70 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located at level of anterior third of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretoryexcretory system present; excretory pore located at level with or posterior to nerve ring. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (longer but plumper and more curved ventrad in male), elongate-conoid, gradually narrowing distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Long setae emerging through first, second and fifth pairs of body pores. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate subcylindrical calamus and ovoid manubrium. Gubernaculum plate-like, with double dorsocaudal apophyses. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, four (five in one male) evenly spaced midventral tubular supplements extending for 144 – 184 µm from cloaca towards anterior end; alveolar supplements absent. Tubular supplements weakly S-shaped, with bifid tips in posteriormost supplements and blunt tips in anteriormost supplements. Posteriormost tubular supplement 29.5 – 34.0 µm anterior to cloaca, anterior to spicules. Sublateral precloacal and caudal sensilla present: two (one pair) precloacal setae at level of spicules and usually two (one pair) caudal setae arranged subventrally. One subventral pair of papilliform sensilla located somewhat posterior to the bases of caudal setae. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 64 – 109 µm long (equal to 8.0 – 15.5 % of total body length), located on right-hand side of intestine (n = 6), posterior genital branch 62 – 102 µm long (equal to 7.6 – 15.0 % of total body length), located on left-hand side of intestine (n = 6). Oviduct a narrow tube. Two offset, oval, sac-like spermathecae located on each (right and left) side of each (anterior and posterior) gonoduct. Spermathecae often filled with oval spermatozoa. Uterus a wide and short tube. Vagina straight, 0.3 – 0.4 times vulval body diameters long; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae absent. Vulva midventral. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Supplements absent. Rectum 1.4 – 1.8 anal body diameters long; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF91FF81FF4E0C20FE4FDD82.taxon	diagnosis	Diagnosis. Leptolaimus septimus sp. n. is particularly characterised by the 679 – 850 µm long body; truncate labial region offset from body contour; cephalic setae 2.5 – 3.5 µm long; amphid located 8.5 – 11.5 µm from anterior end; first body pore located 37.0 – 44.0 µm from anterior end; lateral field originating 26.5 – 37.0 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male with four (rarely five) tubular and without alveolar supplements, tubular supplements weakly S-shaped, with bifid or blunt tips; spicules arcuate and 31.0 – 33.5 µm long. Relationships. The new species is most similar to L. alatus and L. sextus sp. n. in having distinct large papilliform outer labial sensilla. Leptolaimus septimus sp. n. differs from L. alatus in having fewer tubular supplements (4 – 5 vs. 6 – 8 in L. alatus), bifid tips of posteriormost tubular supplements (vs. blunt in L. alatus), longer body (679 – 850 vs. 376 – 595 µm in L. alatus), longer tail in both males (91 – 106 µm, c' = 4.7 – 5.3 vs. 48 – 84 µm, c' = 2.8 – 4.2 in L. alatus) and females (73 – 91 µm, c' = 5.1 – 7.1 vs. 38 – 80 µm, c' = 3.4 – 4.4 in L. alatus). It differs from L. sextus sp. n. in having shorter spicules (31 – 34 µm vs. 39 – 46 µm in L. sextus sp. n.) and longer tail in both males (91 – 106 µm, c' = 4.7 – 5.3 vs. 64 – 71 µm, c' = 2.6 – 3.2 in L. sextus sp. n.) and females (73 – 91 µm, c' = 5.1 – 7.1 vs. 56 – 61 µm, c' = 3.4 – 3.9 in L. sextus sp. n.). From other species of the genus Leptolaimus, males of which have only four evenly spaced tubular supplements (L. gerlachi Murphy, 1966, L. praeclarus Timm, 1961, L. octavus sp. n., some specimens of L. nonus sp. n. and L. elegans), the new species differs in the shape of the labial region with distinct large papilliform outer labial sensilla. It furthermore differs from L. gerlachi in the shape of tubular supplements (S-shaped vs. weakly arcuate in L. gerlachi), shape of gubernaculum (with dorsocaudal vs. with dorsal apophysis in L. gerlachi), shape of spicules (with thin subcylindrical shaft vs. with broad conoid shaft in L. gerlachi), absence of subterminal setae on tail (vs. present in L. gerlachi). It also differs from L. praeclarus in length of spicules (31 – 34 µm vs. 24 µm in L. praeclarus), longer body (679 – 850 µm vs. 442 – 518 µm in L. praeclarus), and anteriormost body setae well posterior to amphid (vs. at amphid base in L. praeclarus). It also differs from L. octavus sp. n. in the absence of bursa-like expansion of lateral field (vs. present in L. octavus sp. n.), shape of tubular supplements (S-shaped with bifid or blunt tips vs. weakly arcuate with dentate tips in L. octavus sp. n.), shape of gubernaculum (with dorsocaudal vs. with dorsal apophysis in L. octavus sp. n.), and number and arrangement of sensilla along pharyngeal region and male tail. It also differs from L. nonus sp. n. in the shape of tubular supplements (S-shaped with bifid or blunt tips vs. weakly arcuate with dentate tips in L. nonus sp. n.), shape of gubernaculum (with dorsocaudal vs. with dorsal apophysis in L. nonus sp. n.), longer spicules (31.0 – 34.0 vs. 17.0 – 26.0 µm in L. nonus sp. n.), position of vulva (midventral vs. right-subventral in L. nonus sp. n.), absence of pars refringens vaginae (vs. present in L. nonus sp. n.), larger body size (679 – 850 µm vs. 403 – 633 µm in L. nonus sp. n.) and other measurements, and number and arrangement of sensilla along pharyngeal region and on male tail. It also differs from L. elegans in the shape of tubular supplements (S-shaped with bifid or blunt tips vs. weakly arcuate with dentate tips in L. elegans), shape of gubernaculum (with dorsocaudal vs. with dorsal apophysis in L. elegans), longer spicules (31.0 – 34.0 vs. 20.0 – 24.0 µm in L. elegans), position of vulva (midventral vs. rightsubventral in L. elegans), absence of pars refringens vaginae (vs. present in L. elegans), and number and arrangement of sensilla along pharyngeal region and on male tail.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF9DFF84FF4E0953FFDFDD17.taxon	description	(Figs 25 C – D, 26; Table 17)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF9DFF84FF4E0953FFDFDD17.taxon	materials_examined	Type material. Holotype male (slide # Type- 8493) and five male and 11 female paratypes (slides # Type- 8493 - Type- 8497) each deposited in the invertebrate type collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Additional material. Five males and six females (slides # 131245 – 131248) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Type locality. Coarse sediment with algae from 45 – 55 m deep, Skagerrak off the west coast of Sweden (N 58 ° 17 ' 32 '', E 11 ° 11 ' 24 ''), 09 August 2011, legit O. Holovachov (six males and 11 females). Additional localities. Gravel, mud and algae from 30 – 70 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 14 '', E 11 ° 05 ' 00 ''), 09 August 2011, legit O. Holovachov (one male and one female); coarse gravel from 30 – 50 m deep, Skagerrak off the westcoast of Sweden (N 58 ° 17 ' 58 '', E 11 ° 10 ' 05 ''), 09 August 2011, legit O. Holovachov (one male and two females); soft mud from 30 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 25 '', E 11 ° 27 ' 30 ''), 11 August 2011, legit O. Holovachov (one male and two females); soft mud from 44 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 37 '', E 11 ° 27 ' 43 ''), 11 August 2011, legit O. Holovachov (two males and one female).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF9DFF84FF4E0953FFDFDD17.taxon	etymology	Etymology. The specific epithet " octavus " is translated as " the eighth " and refers to the sequential number of the new species described in this publication.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF9DFF84FF4E0953FFDFDD17.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; straight or ventrally curved upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 2.2 – 3.1 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 2.0 – 3.0 µm wide at mid-body; originating at level of posterior part of stoma or stoma base (anterior to or at the same level as first body pore) and extending posteriorly to middle of tail. Lateral field expands to create a bursa-like structure along the proximal part of tail in females and in males. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually three pairs of body pores are present along pharyngeal region; numerous body pores scattered over rest of the body. Anteriormost body pore located at level of stoma base or procorpus. Labial region truncate, continuous with body contour, lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla setiform, equal to 30 – 50 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located at level of anterior third of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system indistinct. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (more curved ventrad in male), conoid, gradually narrowing distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Short setae emerging through first, second and third pairs of body pores. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with subcylindrical arcuate calamus and ovoid shaft. Gubernaculum plate-like, with double dorsal apophyses. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, four evenly spaced midventral tubular supplements extending for 110 – 133 µm from cloaca towards anterior end; alveolar supplements absent. Tubular supplements weakly S-shaped, with dentate tips. Posteriormost tubular supplement 27.0 – 29.5 µm anterior to cloaca, anterior to spicules. Sublateral precloacal and caudal sensilla present: two (one pair) precloacal setae at level of spicules and usually four (two pairs) caudal setae arranged in one subventral and one subdorsal pair. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 72 – 110 µm long (equal to 11.6 – 17.5 % of total body length), located on right-hand side of intestine (n = 5), posterior genital branch 85 – 98 µm long (equal to 13.5 – 15.7 % of total body length), located on left-hand side of intestine (n = 5). Oviduct a narrow tube. Two offset, oval, sac-like spermathecae located on each (right and left) side of each (anterior and posterior) gonoduct. Spermathecae often filled with oval spermatozoa. Uterus a wide and short tube. Vagina straight, 0.3 times vulval body diameters long; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae absent. Vulva midventral. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Supplements absent. Rectum 1.0 – 1.3 anal body diameters long; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF9DFF84FF4E0953FFDFDD17.taxon	diagnosis	Diagnosis. Leptolaimus octavus sp. n. is particularly characterised by the 541 – 638 µm long body; truncate labial region continuous with body contour; cephalic setae 1.5 – 2.0 µm long; amphid located 8.5 – 12.0 µm from anterior end; first body pore located 31.5 – 41.0 µm from anterior end; lateral field originating 26.0 – 40.0 µm from anterior end and expanding into bursa-like structure along the proximal part of the tail; female without supplements, vagina without pars refringens, vulva midventral; male with four tubular and without alveolar supplements, tubular supplements weakly S-shaped with dentate tips; spicules arcuate and 30.0 – 31.5 µm long. Relationships. Leptolaimus octavus sp. n. is unique among other species of Leptolaimus in having a bursa-like expansion of the lateral field along the proximal part of the tail of both females and males. It should be further compared with other species of the genus Leptolaimus, males of which have only four evenly spaced tubular supplements, i. e.: L. gerlachi, L. praeclarus, L. septimus sp. n. (see above), some specimens of L. nonus sp. n. and L. elegans. The new species differs from L. gerlachi in smaller body (541 – 638 µm vs. 760 – 840 µm in L. gerlachi), shape of tubular supplements (with dentate tips vs. with bifid tips in L. gerlachi), shape of spicules (with thin subcylindrical shaft vs. with broad conoid shaft in L. gerlachi), and absence of subterminal setae on tail (vs. present in L. gerlachi). It differs from L. praeclarus in length of spicules (30.0 – 31.5 µm vs. 24.0 µm in L. praeclarus) and anteriormost body setae well posterior to amphid (vs. at amphid base in L. praeclarus). It differs from L. nonus sp. n. in longer stoma (30 – 36 µm vs. 17 – 22 µm in L. nonus sp. n.), longer spicules (30.0 – 31.5 µm vs. 17.0 – 26.0 µm in L. nonus sp. n.), position of vulva (midventral vs. right-subventral in L. nonus sp. n.), and absence of pars refringens vaginae (vs. present in L. nonus sp. n.). It furthermore differs from L. elegans in having longer stoma (30 – 36 µm vs. 18 – 24 µm in L. elegans), longer spicules (30.0 – 31.5 µm vs. 20.0 – 24.0 µm in L. elegans), position of vulva (midventral vs. right-subventral in L. elegans).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF98FFFAFF4E0EE0FFAFD894.taxon	description	(Figs 27, 28 A – B; Table 18)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF98FFFAFF4E0EE0FFAFD894.taxon	materials_examined	Material examined. Five males and 11 females (slides # 130723 – 130725) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Habitat and locality. Muddy sand from 8 – 15 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 09 '', E 11 ° 27 ' 54 ''), 11 August 2011, legit O. Holovachov (five males and 11 females).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF98FFFAFF4E0EE0FFAFD894.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; ventrally curved or coiled upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 1.6 – 2.0 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 1.5 – 2.0 µm wide at mid-body; originating at level of posterior part of metacorpus (close to third body pore) and extending posteriorly to distal part of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually four pairs of body pores are present along pharyngeal region; several body pores scattered over rest of the body. Anteriormost body pore located at level of stoma, just posterior to amphid. Labial region rounded, continuous with body contour, lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla setiform, equal to 130 – 170 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located at level of middle of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system indistinct. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (shorter and more curved ventrad in male), elongate-conoid, gradually narrowing distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Long setae emerging through first, second and fourth pairs of body pores. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate subcylindrical calamus and ovoid manubrium. Gubernaculum plate-like, with arcuate dorsal apophysis. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, seven unevenly spaced midventral tubular supplements extending for 227 – 242 µm from cloaca towards anterior end; alveolar supplements absent. There is a distinct gap between the second (from cloaca) and the third (from cloaca) tubules. Tubular supplements sickle-shaped, with truncate tips. Posteriormost tubular supplement 32.0 – 34.0 µm anterior to cloaca, anterior to spicules. Sublateral precloacal and caudal sensilla present: one right precloacal setae at level of spicules and usually seven caudal setae arranged subventrally and subdorsally. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 78 – 131 µm long (equal to 9.8 – 16.2 % of total body length), located on right-hand (n = 6) or left-hand (n = 1) side of intestine, posterior genital branch 71 – 135 µm long (equal to 9.1 – 16.6 % of total body length), located on left-hand (n = 6) or right-hand (n = 1) side of intestine. Oviduct a narrow tube. One offset, oval, sac-like spermatheca located on right side of anterior gonoduct and one on left side of posterior gonoduct. Spermathecae filled with oval spermatozoa. Uterus a wide and short tube. Vagina straight, 0.3 times vulval body diameters long; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae absent. Vulva rightventrosublateral. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Supplements absent. Rectum 1.4 – 2.0 anal body diameters long; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF98FFFAFF4E0EE0FFAFD894.taxon	diagnosis	Diagnosis (supplemented with literature data). Leptolaimus macer is particularly characterised by the 698 – 862 µm long body; rounded labial region continuous with body contour; cephalic setae 6.0 – 8.0 µm long; amphid located 8.5 – 13.0 µm from anterior end; first body pore located 14.0 – 20.0 µm from anterior end; lateral field originating 66.0 – 91.5 µm from anterior end; female without supplements, vagina without pars refringens, vulva right ventrosublateral; male with seven tubular and without alveolar supplements, tubular supplements sickleshaped with blunt tips; spicules arcuate and 15.0 – 18.5 µm long.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFF98FFFAFF4E0EE0FFAFD894.taxon	discussion	Remarks. Current specimen agrees well with the type population of L. macer in general morphology, measurements, shape, number and position of tubular supplements, shape of spicules and gubernaculum. Females are described for the first time in this species.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFE6FFFCFF4E0A62FFFFDA7F.taxon	description	(Figs 29, 30, 31 A – B; Table 19)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFE6FFFCFF4E0A62FFFFDA7F.taxon	materials_examined	Material examined. 41 males and 35 females (slides # 130915 – 130928) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Habitat and locality. Mud from 30 – 39 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 13 '', E 11 ° 27 ' 31 ''), 21 August 2010, legit M. Clément (five males and eight females); soft mud from 30 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 25 '', E 11 ° 27 ' 30 ''), 11 August 2011, legit O. Holovachov (six males and four females); soft mud from 44 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 37 '', E 11 ° 27 ' 43 ''), 11 August 2011, legit O. Holovachov (19 males and 13 females); muddy sediment from 53 m deep, Skagerrak off the west coast of Sweden (N 58 ° 20 ' 06 '', E 11 ° 09 ' 24 ''), 09 August 2011, legit O. Holovachov (two males and one female); gravel, mud and algae from 30 – 70 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 14 '', E 11 ° 05 ' 00 ''), 09 August 2011, legit O. Holovachov (two males and two females); muddy sand from 25 – 50 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 20 '', E 11 ° 09 ' 26 ''), 09 August 2011, legit O. Holovachov (two males and four females); coarse sediment with algae from 45 – 55 m deep, Skagerrak off the west coast of Sweden (N 58 ° 17 ' 32 '', E 11 ° 11 ' 24 ''), 09 August 2011, legit O. Holovachov (four males and two females); muddy sediment from 55 – 70 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 19 '', E 11 ° 04 ' 55 ''), 09 August 2011, legit O. Holovachov (two males and two females).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFE6FFFCFF4E0A62FFFFDA7F.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; straight or ventrally curved upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 2.6 – 3.2 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 1.5 – 3.0 µm wide at mid-body; originating at level of metacorpus (posterior to first body pore) and extending posteriorly to middle of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually four pairs of body pores are present along pharyngeal region; several body pores scattered over rest of the body. Anteriormost body pore located at level of procorpus. Labial region rounded, continuous with body contour, lips fused. Inner labial sensilla indistinct. Outer labial sensilla indistinct under the light microscope, small papilliform with terminal pore as seen under SEM; located on the anterior surface of lips. Cephalic sensilla setiform, equal to 40 – 60 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located at level of middle of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system present; excretory pore located posterior to nerve ring. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (more curved ventrad in male), elongate-conoid, gradually narrowing distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Long setae emerging through all body pores over entire body. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate cylindrical calamus and ovoid manubrium. Gubernaculum plate-like, with dorsal apophysis. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, seven (rarely eight) evenly spaced midventral tubular supplements extending for 303 – 379 µm from cloaca towards anterior end; alveolar supplements absent. Tubular supplements weakly arcuate in shape, with dentate tips. Posteriormost tubular supplement 31 – 40 µm anterior to cloaca, anterior to spicules. Sublateral precloacal and caudal sensilla present: two (one pair) precloacal setae at level of spicules and usually eight (four pairs) caudal setae arranged in two subventral and two subdorsal pairs. One unpaired seta located on the left subdorsal side just posterior to cloaca. One subventral pair of papilliform sensilla located at the bases of the second (from cloaca) pair of caudal setae. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 145 – 183 µm long (equal to 17.0 – 20.3 % of total body length), located on right-hand side of intestine (n = 8), posterior genital branch 121 – 186 µm long (equal to 14.1 – 20.7 % of total body length), located on left-hand side of intestine (n = 8). Oviduct a narrow tube. Two offset, oval, sac-like spermathecae located on each (right and left) side of each (anterior and posterior) gonoduct. Spermathecae and oviducts filled with oval spermatozoa. Uterus a wide and long tube. Vagina straight, 0.2 – 0.3 times vulval body diameters long; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae present, each side is semicircular in shape. Vulva midventral, a transverse slit with small liplets as seen under SEM. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Supplements absent. Rectum 0.8 – 1.1 anal body diameters long; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFE6FFFCFF4E0A62FFFFDA7F.taxon	diagnosis	Diagnosis (supplemented with literature data). Leptolaimus septempapillatus is particularly characterised by the 762 – 965 µm long body; rounded labial region weakly offset from body contour; cephalic setae 2.0 – 3.0 µm long; amphid located 8.0 – 14.0 µm from anterior end; first body pore located 29 – 39 µm from anterior end; lateral field originating 57.0 – 67.0 µm from anterior end; female without supplements, vagina with semicircular pars refringens, vulva midventral; male with seven (rarely eight) tubular and without alveolar supplements, tubular supplements weakly arcuate with dentate tips; spicules arcuate and 22.0 – 28.5 µm long.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFE6FFFCFF4E0A62FFFFDA7F.taxon	discussion	Remarks. Current specimens agree well with the type specimens in general morphology, body size, measurements, shape of anterior end and amphids, number and shape of supplements, shape of spicules and gubernaculum. The only differences being slightly more anterior position of the amphid (8.0 – 11.0 µm vs. 13.0 – 14.0 µm from anterior end in type specimens) and slightly longer spicules (26.0 – 28.5 µm vs. 22.0 – 26.0 µm long in type specimens). Unfortunately, the original description of this species is insufficiently illustrated to allow any further comparison. This species is very similar to Leptolaimus elegans (described below) and was considered a junior synonym of it (Fadeeva & Mordukhovich, 2007; Platt & Warwick, 1988), however, present study revealed consistent differences in male and female morphology between both species (See Table 22). L. septempapillatus as re-described here, can be separated from L. elegans based on following features: wider labial region (4 – 6 µm vs. 3.5 – 4 µm in L. elegans), relatively shorter pharynx (b = 5.6 – 6.5 vs. b = 4.1 – 5.4 in L. elegans), longer spicules (22 – 29 µm vs. 20 – 24 µm in L. elegans), orientation of vulva (midventral vs. right-subventral in L. elegans), presence of pars refringens vaginae (vs. absent in L. elegans).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFE0FFF3FF4E09C8FFEBDD5F.taxon	description	(Figs 31 C – D, 32; Table 20)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFE0FFF3FF4E09C8FFEBDD5F.taxon	materials_examined	Material examined. 17 males and 86 females (slides # 130932 – 130940, 130942, 130944 – 130947) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Habitat and locality. Muddy clay from 52.5 m deep, near Landsort Island, Baltic Sea off the east coast of Sweden (N 58 ° 46 ' 00 '', E 17 ° 49 ' 52 ''), 26 May 2011, legit C. Raymond (one male and nine females); mud from the bottom, Bothnian Gulf off the east coast of Sweden (N 60 ° 36 ' 05 '', E 18 ° 44 ' 55 ''), 17 May 2011, legit J. Albertsson (seven males and 32 females); mud from 38 m deep, Bothnian Gulf off the east coast of Sweden (N 60 ° 24 ' 21 '', E 18 ° 29 ' 10 ''), 19 May 2011, legit J. Albertsson (two males and nine females); mud from 86 m deep, Bothnian Gulf off the est coast of Sweden (N 62 ° 49 ' 07 '', E 18 ° 23 ' 44 ''), 23 May 2011, legit J. Albertsson (seven males and 36 females).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFE0FFF3FF4E09C8FFEBDD5F.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; straight or ventrally curved upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 1.0 – 1.5 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 2.0 – 3.0 µm wide at mid-body; originating at level of metacorpus (posterior to first body pore) and extending posteriorly to proximal part of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually three pairs of body pores are present along pharyngeal region, and one at level of cardia; numerous body pores scattered over rest of the body. Anteriormost body pore located at level of procorpus. Labial region rounded, continuous with body contour, lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla setiform, equal to 30 – 60 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located at level of middle of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system present; excretory pore located posterior to nerve ring. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (more curved ventrad in male), elongate-conoid to subcylindrical, gradually narrowing distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Long setae emerging through first, second and third pairs of body pores. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate cylindrical calamus and ovoid manubrium. Gubernaculum plate-like, with dorsal apophysis. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, five evenly spaced midventral tubular supplements extending for 183 – 214 µm from cloaca towards anterior end; alveolar supplements absent. Tubular supplements weakly arcuate in shape, with dentate tips. Posteriormost tubular supplement 45 – 57 µm anterior to cloaca, anterior to spicules. Sublateral precloacal and caudal sensilla present: two (one pair) precloacal setae at level of spicules and usually eight (four pairs) caudal setae arranged in two subventral and two subdorsal pairs. One subventral pair of papilliform sensilla located at the bases of the second (from cloaca) pair of caudal setae. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 61 – 132 µm long (equal to 10.8 – 21.2 % of total body length), located on right-hand side of intestine (n = 7), posterior genital branch 78 – 122 µm long (equal to 13.7 – 20.0 % of total body length), located on left-hand side of intestine (n = 7). Oviduct a narrow tube. Two offset, oval, sac-like spermathecae located on each (right and left) side of each (anterior and posterior) gonoduct. Spermathecae often filled with oval spermatozoa. Uterus a wide and short tube. Vagina straight; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae absent. Vulva right ventrosublateral. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Supplements absent. Rectum 1.4 – 1.9 anal body diameters long; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFE0FFF3FF4E09C8FFEBDD5F.taxon	diagnosis	Diagnosis (supplemented with literature data). Leptolaimus elegans is particularly characterised by the 493 – 800 µm long body; rounded labial region continuous with body contour; cephalic setae 1.5 – 4.0 µm long; amphid located 8.0 – 12.0 µm from anterior end; first body pore located 24.0 – 36.0 µm from anterior end; lateral field originating 50.0 – 75.0 µm from anterior end; female without supplements, vagina without pars refringens, vulva right ventrosublateral; male with five – eight tubular and without alveolar supplements, tubular supplements weakly arcuate with dentate tips; spicules arcuate and 20.0 – 24.0 µm long.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFE0FFF3FF4E09C8FFEBDD5F.taxon	discussion	Remarks. Current specimens agree well with the type specimen in general morphology, measurements and shape of amphids, the only difference being shorter cephalic setae (1.5 – 2.0 µm vs. 4.0 µm in type specimen). Unfortunately, the original description of this species is insufficiently illustrated and does not include any data about males to allow any further comparison. Therefore, our identification is mainly based on the redescription of L. elegans published by Lorenzen (1972 b). When comparing to specimens described by Lorenzen (1972 b), present specimens mainly differ in having constant number of supplements in males (5 vs. 5 – 8), shorter body (493 – 622 µm vs. 635 – 800 µm), shorter cephalic setae (1.5 – 2.0 µm vs. 3.0 – 3.5 µm). On the other hand, other body measurements, shape and length of spicules, shape of gubernaculum, number and arrangement of sensilla along pharyngeal region and on male tail are identical between populations.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFEFFFECFF4E0E12F8AED987.taxon	description	(Figs 28 C – D, 33; Table 21)	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFEFFFECFF4E0E12F8AED987.taxon	materials_examined	Type material. Holotype male (slide # Type – 8498) and six male and eight female paratypes (slides # Type- 8498 - Type- 8500) deposited in the invertebrate type collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Additional material. Three males and nine females (slides # 131249 – 131252) deposited in the general invertebrate collection of the Department of Zoology, Swedish Museum of Natural History, Stockholm, Sweden. Type locality. Algae from 15 – 55 m deep, Skagerrak off the west coast of Sweden (N 58 ° 17 ' 24 '', E 11 ° 10 ' 48 ''), 09 August 2011, legit O. Holovachov (seven males and eight females). Additional localities. Gravel, mud and algae from 30 – 70 m deep, Skagerrak off the west coast of Sweden (N 58 ° 22 ' 14 '', E 11 ° 05 ' 00 ''), 09 August 2011, legit O. Holovachov (two females); algae from 20 – 40 m deep, Skagerrak off the west coast of Sweden (N 58 ° 21 ' 49 '', E 11 ° 04 ' 42 ''), 09 August 2011, legit O. Holovachov (two males and three females); coarse sediment with algae from 45 – 55 m deep, Skagerrak off the west coast of Sweden (N 58 ° 17 ' 32 '', E 11 ° 11 ' 24 ''), 09 August 2011, legit O. Holovachov (four females); soft mud from 30 m deep, Gullmarn Fjord near Fiskebäckskil, Sweden (N 58 ° 15 ' 25 '', E 11 ° 27 ' 30 ''), 11 August 2011, legit O. Holovachov (one male).	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFEFFFECFF4E0E12F8AED987.taxon	etymology	Etymology. The specific epithet " nonus " is translated as " the ninth " and refers to the sequential number of the new species described in this publication.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFEFFFECFF4E0E12F8AED987.taxon	description	Description. Adult. Body tapering anteriorly in pharyngeal region and posteriorly on tail; ventrally curved upon fixation, more strongly curved ventrad in posterior part in males. Maximum body diameter at vulva in female; male body more cylindrical. Cuticle annulated; annuli 1.2 – 2.0 µm wide at mid-body, without ornamentation. Lateral field present, consists of single ala (two incisures), 1.5 – 3.0 µm wide at mid-body; originating at level of metacorpus (posterior first body pore) and extending posteriorly to proximal part of tail. Prominent body pores in sublateral position at both sides of lateral field present, arising from oval lateral epidermal gland cells; usually three pairs of body pores are present along pharyngeal region; numerous body pores scattered over rest of the body. Anteriormost body pore located at level of stoma base or procorpus. Labial region rounded, continuous with body contour, lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla setiform, equal to 40 – 70 % of labial region diameter. Subcephalic and cervical sensilla and ocelli absent. Amphidial fovea round, located at level of middle of stoma. Nerve ring surrounding pharynx at level of anterior part of isthmus. Hemizonid not seen. Secretory-excretory system present; excretory pore located posterior to nerve ring. Buccal cavity uniformly tubular: cheilostom and gymnostom short, undifferentiated; stegostom tubular, with uniformly thickened lumen. Pharynx muscular, cylindrical anteriorly, with distinct oval basal bulb; valvular apparatus absent. Anterior cylindrical part of pharynx subdivided by breaks in muscular pharyngeal tissue into cylindrical procorpus, cylindrical metacorpus and narrow isthmus. Pharyngeal glands and their orifices indistinct. Cardia cylindrical, its posterior part embedded in intestine. Tail similar in shape in both sexes (more curved ventrad in male), elongateconoid, gradually narrowing distally. Three caudal glands present, their nuclei are incaudal. Spinneret functional. Male. Papillae emerging through body pores. Reproductive system diorchic; anterior testis outstretched; posterior one reflexed. Spicules paired, symmetrical, with arcuate subcylindrical calamus and ovoid manubrium. Gubernaculum plate-like, with weak double dorsal apophyses. Accessory apparatus composed of one midventral precloacal papilliform sensillum located on anterior cloacal lip, four-five midventral evenly spaced tubular supplements extending for 73 – 123 µm from cloaca towards anterior end; alveolar supplement absents. Tubular supplements weakly arcuate in shape, with dentate tips. Posteriormost tubular supplement 16 – 32 µm anterior to cloaca, anterior to spicules. Sublateral caudal sensilla present: usually eight (four pairs) caudal setae arranged in two subventral and two subdorsal pairs. Precloacal setae absent. One subventral pair of papilliform sensilla located at the bases of the second (from cloaca) pair of caudal setae. Aberrant male (# 1). Similar to typical males except for the smaller body size and presence of only two midventral tubular supplements extending for 45 µm from cloaca towards anterior end. Aberrant male (# 2). Similar to typical males except for the smaller body size, smaller spicules and absence of tubular supplements. Female. Reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously. Anterior genital branch 60 – 98 µm long (equal to 10.9 – 16.6 % of total body length), located on right-hand side of intestine (n = 5), posterior genital branch 36 – 93 µm long (equal to 6.6 – 16.3 % of total body length), located on left-hand side of intestine (n = 5). Oviduct a narrow tube. Two offset, oval, sac-like spermathecae located on each (right and left) side of each (anterior and posterior) gonoduct. Spermathecae filled with oval spermatozoa. Uterus a wide and short tube. Vagina straight, 0.2 – 0.5 times vulval body diameters long; pars proximalis vaginae encircled by single sphincter muscle; pars refringens vaginae present, bacilliform in shape. Vulva right-subventral. Epiptygmata and sensitive structures around vulva (advulval sensilla) absent. Supplements absent. Rectum 1.2 – 2.0 anal body diameters long; surrounded by three gland-like cells at intestine-rectum junction.	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
AD26453DFFEFFFECFF4E0E12F8AED987.taxon	diagnosis	Diagnosis (two aberrant males excluded). Leptolaimus nonus sp. n. is particularly characterised by the 403 – 633 µm long body; rounded labial region continuous with body contour; cephalic setae 1.5 – 3.0 µm long; amphid located 8.0 – 10.0 µm from anterior end; first body pore located 16.5 – 29.0 µm from anterior end; lateral field originating 47.0 – 99.0 µm from anterior end; female without supplements, vagina with bacilliform pars refringens, vulva right-subventral; male with 4 – 5 tubular and without alveolar supplements, tubular supplements weakly arcuate with dentate tips; spicules arcuate and 17.0 – 26.0 µm long. Relationships. Leptolaimus nonus sp. n. is most similar to the population of L. elegans described here in the number of supplements, shape of labial region (without distinct outer labial sensilla) and right-subventral position of vulva. It can however be separated from L. elegans based on the following features: pars refringens vaginae present (vs. absent in L. elegans), sensilla emerging through body pores are papilliform (vs. setiform in L. elegans) and precloacal pair of setae in male is missing (vs. present in L. elegans). Review of the genus Leptolaimus de Man, 1876 = Aplectus Cobb, 1914 op. Hope & Murphy, 1972 = Boveelaimus Alekseev & Rassadnikova, 1977 (Alekseev, 1979) op. Holovachov & Boström, 2004 = Dermatolaimus Steiner, 1916 op. De Coninck, 1965 = Halaphanolaimus Southern 1914 op. Holovachov & Boström, 2004 = Polylaimium Cobb, 1920 syn. n. = Leptolaimus (Alveolaimus) Alekseev & Rassadnikova, 1977 op. Holovachov & Boström, 2004 = Leptolaimus (Boveelaimus) Alekseev & Rassadnikova, 1977 op. Holovachov & Boström, 2004 = Leptolaimus (Tubulaimus) Alekseev & Rassadnikova, 1977 op. Holovachov & Boström, 2004 Diagnosis (emended after Holovachov & Boström, 2010). Cuticule annulated, annulation smooth. Lateral ala present, as a single band of smooth cuticle. Epidermal glands present, opening via body pores in two sublateral rows on each body side. Somatic sensilla present, connected to epidermal glands along the body, their number is species-specific. Labial region rounded or truncate. First annules appear anterior to cephalic setae bases. Sclerotized cephalic capsule absent. Inner labial sensilla indistinct. Outer labial sensilla indistinct or papilliform, located on anterior surface of lips. Cephalic sensilla papilliform or setiform; their bases located anterior to amphids. Subcephalic sensilla absent. Ocelli and deirid absent. Amphidial fovea ventrally unispiral. Secretoryexcretory system: renette cell oval, located along ventral side of cardia and anterior part of intestine; excretory pore opens posterior to nerve ring; excretory canal short, excretory ampulla present. Buccal cavity tubular: cheilostom undifferentiated; gymnostom undifferentiated or short barrel-shaped; stegostom tubular. Pharynx subdivided by breaks in muscular pharyngeal tissue into narrow procorpus, somewhat wider metacorpus, narrow isthmus and basal bulb; muscularized; pharyngeal lumen within bulbus is thicker and more cuticularised than elsewhere along the pharynx; valvular apparatus absent. Cardia enveloped by intestine in its posterior part. Female reproductive system didelphic, amphidelphic; ovary branches reflexed antidromously; spermathecae offset, sac-like; unpaired (two in total) or paired (four in total); located on each side of each gonoduct; uterus short or long; vulva equatorial, midventral or left- or right-subventral; vagina straight, pars proximalis vaginae encircled by a single sphincter muscle; pars refringens vaginae present or absent. Male reproductive system diorchic; testes opposed with anterior testis outstretched and posterior one reflexed; spicules arcuate; gubernaculum rectangular or plate-like, with apophysis. Copulatory apparatus: 2 – 56 alveolar supplements (present or absent), 1 – 16 midventral tubular supplements (present or absent); single midventral precloacal papilliform sensillum located on the anterior cloacal lip, sometimes additional midventral precloacal setiform sensillum located between posteriormost supplement and cloacal opening; a pair of precloacal setae and several pairs of subventral and subdorsal caudal setae, unpaired setae may be present. Females may also have either tubular (1 – 4) or tubular and alveolar supplements. Tail conoid, elongate or subcylindrical. Three caudal glands present, their nuclei are incaudal. Spinneret functional, weakly cuticularised. Body length 410 – 970 621 – 735 430 – 518 926 – 1313 1460 – 1935 a 20 – 38 38 – 45 26 – 35 20 – 26 32 – 52 b 4.0 – 6.3 5.3 – 6.1 3.8 – 4.5 4.7 – 5.4 5.9 – 7.6 c 5.9 – 10.4 7.1 – 9.1 6.9 – 8.3 10.0 – 12.7 10.7 – 14.7 c' (male) 3.6 – 5.8 4.8 4.3 – 5.7 2.3 – 3.0 3.3 – 4.2 c' (female) 4.0 – 7.8 7.2 – 8.7? 3.2 – 3.3 4.1 – 5.7 V (%) 45 – 53 48 – 50 51 – 53 48 46 – 51 Labial region diameter 4.0 – 8.0 5.0 – 6.0 4.0 – 5.0 5.8 – 6.4 7 – 13 Cephalic setae length 2.0 – 4.0 1.5 – 4.0 2.0 – 3.0 2.5 – 3.2 3.5 – 8.0 Amphid from ant. end 6.5 – 8.0 8.0 – 9.0 9 – 11 * 6 – 7 8.5 – 11 First body pore from ant. end ~ 17 * 17 – 24 ~ 27 *? 38 – 51 Lateral field from ant. end? 46 – 47 ?? 72 – 92 Stoma length 15 – 21 18 – 21? 30 – 32 32 – 40 Tail length (male) 70 – 95 76 60 – 68? 120 – 150 Tail length (female) 52 – 98 90 – 99 ?? 115 – 141 Spicule length (along arc) 26 – 34 16 – 20 15 – 16 chord 68 – 70 47 – 70 Gubernaculum apophysis dorsal dorsal dorsal dorsal dorsal Shape of alveolar supplements NA NA NA NA NA Tips of tubular supplements? anchor-like anchor-like bifid or round anchor-like Vagina shape straight straight ?? straight Vulva orientation? midventral ?? midventral Pars refringens vaginae? present ?? absent Male supplements: alveolar 0 0 0 0 0 tubular (anterior) 1 1 1 1 1 – 3 tubular (posterior) 3 + 1 3 + 1 4 – 5 11 – 13 5 – 8 Female supplements: ...... continued on the next page Body length 493 – 800 780 – 900 600 – 830 762 – 965 a 25 – 38 17 – 29 21 – 46 27 – 45 b 4.1 – 5.4 4.3 – 4.6 4.8 – 5.8 5.6 – 6.5 c 6.0 – 8.0 7.8 – 8.5 6.0 – 8.0 7.3 – 10.0 c' (male) 4.2 – 4.8 4.0 – 6.1 3.5 – 9.0 4.3 – 5.3 c' (female) 5.5 – 8.3 4.0 4.5 – 9.0 5.5 – 6.4 V (%) 49 – 52 49 50 – 54 49 – 52 Labial region diameter 3.5 – 4 8.0 – 9.0 4 – 6 4 – 6 Cephalic setae length 1.5 – 4 3 – 4 2 – 3 2 – 3 Amphid from ant. end 8 – 12 ~ 18 * 5 – 12 8 – 14 First body pore from ant. end 24 – 36 ~ 59 *? 29 – 39 Lateral field from ant. end 50 – 75 ?? 57 – 67 Stoma length 18 – 24 30 17 – 25 17 – 26 Tail length (male) 76 – 83 95 – 110 * 80 – 108 85 – 117 Tail length (female) 75 – 93 95 * 90 – 133 90 – 119 Spicule length (along arc) 20 – 24 R 39 – 43 / L 48 – 54 24 – 29 22 – 29 Gubernaculum apophysis dorsal dorsal dorsal dorsal Shape of alveolar supplements NA NA NA NA Tips of tubular supplements dentate bifid dentate dentate Vagina shape straight ?? straight Vulva orientation right-subventral ?? midventral Pars refringens vaginae absent? absent present Male supplements: alveolar 0 0 0 0 ...... continued on the next page	en	Holovachov, Oleksandr, Boström, Sven (2013): Swedish Plectida (Nematoda). Part 4. The genus Leptolaimus de Man, 1876. Zootaxa 3739 (1): 1-99, DOI: 10.11646/zootaxa.3739.1.1, URL: http://dx.doi.org/10.11646/zootaxa.3739.1.1
