taxonID	type	description	language	source
EC0687D9FFCBE14FFF35FC3896F90A97.taxon	type_taxon	Type species. Aulodrilus limnobius Bretscher, 1899	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFCBE14FFF35FC3896F90A97.taxon	diagnosis	Diagnosis. Medium sized worms with numerous chaetae (up to 16 in ventral bundles) and unsegmented tails. Short and slightly sigmoid hair chaetae present or absent. Lateral wings on crotchet chaetae present or absent. Vasa deferentia usually about as long as atrium, with uniform width, connected to apical end of atrium. Atria globular to tubular in shape, laterally joined by a solid, single prostate gland through a short stalk. Protrusible, true penes usually present without cuticular sheaths or eversible pseudopenes. Loose sperm masses in spermathecae, not forming spermatozeugmata. Coelomocytes sparse or absent. Duplication and forward shift of genital organs often occur. Single embryo in cocoon. Dwelling in mud tubes. The diagnosis is modified from Brinkhurst (1971), Hrabě (1981) and Finogenova and Arkhipova (1994).	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFCBE14FFF35FC3896F90A97.taxon	discussion	Remarks. Brinkhurst (1971) listed three diagnostic characters of the genus Aulodrilus by which he afforded subfamilial rank: 1) prostates attached to atria by broad bases, 2) sperm in bundles (masses) in spermathecae, 3) coelomocytes absent. Subsequently Giani et al. (1984) corrected the first feature, because prostate glands of A. pluriseta and A. limnobius are stalked on the atrium like those of Tubificinae, and they invalidated the subfamily Aulodrilinae. At the genus level, along with other two characters listed above, short vas deferentia, globular or cylindrical atria, large eversible pseudopenes, and unsegmented posterior ends have been used as diagnostic characters (Brinkhurst 1971; Hrabě 1981; Finogenova & Arkhipova 1994). Finogenova and Arkhipova (1994) emphasized a forward shift of reproductive organs and multiplication of gonads as diagnostic characters of Aulodrilus. It is reasonable to regard the subfamily Aulodrilinae invalid and to maintain the genus Aulodrilus in the subfamily Tubificinae. Among Tubificinae, lateral expansions of somatic chaetae occur only in this genus; however, not all congeners have this feature, and species also vary in expression of the other characters listed above. The genusdiagnostic characters of Aulodrilus are evaluated in the " Discussion ".	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFCBE14AFF35F8C790D60DE2.taxon	description	(Figures 1, 2)	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFCBE14AFF35F8C790D60DE2.taxon	materials_examined	Material examined. Japan: 30 immature specimens, Chubetsu-numa at 1790 m alt. of Mt. Chubetsu-dake, Taisetu Mountains, Hokkaido, 26 July 1983. 8 immature specimens, Lake Takkobu, Kushiro City, Hokkaido, 23 July 2003, coll. T. Ito. 12 immature specimens, Lake Bankei-numa at 910 m alt. of Mt. Soranuma-dake, Sapporo City, Hokkaido, 8 Aug. 1982, 2 July 1983. 3 immature specimens, offshore Lake Okotanpe, Chitose City, Hokkaido (15 – 20 m in depth), 4 Aug. 1984. 13 mature and 10 immature specimens, rice paddy in Nozawa, Aomori City, Aomori Prefecture, 28 June, 2007. 4 immature specimens, rice paddy in Kanagi, Goshogawara City, Aomori Prefecture, 1 July 2000. 3 immature specimens, Lake Hiyamizu-numa, Tsugaru City, 1 July 2007. 10 immature specimens, rice paddy in Inakadate Village, Aomori Prefecture, 3 June 2011. 8 immature specimens, rice paddy in Utarube, Towada City, Aomori Prefecture, 5 June 2011. 3 mature and 4 immature specimens, rice paddy in Shin-hoshi, Hirosaki City, Aomori Prefecture, 29 June, 2014. 10 mature and 25 immature specimens, rice paddy in Zatoishi, Hirosaki City, Aomori Prefecture, 18 June 2011. 5 immature specimens, rice paddy in Orikasa, Hirosaki City, Aomori Prefecture, 25 June 2011. 5 mature and 15 immature specimens, rice paddy in Ichoda, Hirosaki City, Aomori Prefecture, 25 June 2011. 13 immature specimens, a marsh in Sakamoto, Hirosaki City, Aomori Prefecture, 25 Sep. 2011. 5 mature and 7 immature specimens, rice paddy in Ohkawara, Kuroishi City, Aomori Prefecture, 16 Aug. 2011. 3 immature specimens, Aseishigawa Reservoir, Kuroishi City, Aomri Prefecture, 4 Aug. 2014. 5 mature and 7 immature specimens, rice paddy in Shichinohe Town, Aomori Prefecture, 24 June 2007, 16 Aug. 2011. 20 immature specimens, rice paddy in Ishizawa, Gonohe Town, Aomori Prefecture, 16 Aug. 2011. 5 immature specimens, rice paddy in Muranaka, San-nohe Town, Aomori Prefecture, 16 Aug. 2011. 10 mature and 20 immature specimens, rice paddy in Iwaihana, Hachimantai City, Iwate Prefecture, 15 July 2007. 2 immature specimens, Lake Hachiro-gata, Akita Prefecture (3.6 m depth), 9 July, 2005. 1 immature specimen, a marsh in Osawa near Lake Tazawa, Senboku City, Akita Prefecture, 29 Sep. 2007. 3 mature and 20 immature specimens, rice paddy in Gojome Town, Akita Prefecture, 17 July 2011. 10 mature and 9 immature specimens, rice paddy in Hinai, Odate City, Akita Prefecture, 22 July 2011. 5 immature specimens, rice paddy in Akafuchi, Kazuno City, Akita Prefecture, 16 July, 2007. 100 mature, 20 immature specimens, rice paddy in Tajiri, Osaki City, Miyagi Prefecture, 25 Jul. 2007, coll. M. Kawase. 5 mature and 18 immature specimens, rice paddy in Tome City, Miyagi Prefecture, 27 May 2007. 3 mature specimens, rice paddy in Fujishima, Tsuruoka City, Yamagata Prefecture, 30 June 2006, coll. M. Kawase. 1 immature specimen, rice paddy in Obanazawa City, Yamagata Prefecture, 9 Aug. 1990. 5 immature specimens, rice paddy in Tomioka City, Gunma Prefecture, 16 Aug. 1985. 2 mature and 28 immature specimens, rice paddy in Oki, Takasaki City, Gunma Prefecture, 24 July 1995. 4 mature specimens, a small current in Ozegahara mire, Gunma Prefecture, 26 Jul. 1995, 8 May 1998. 3 mature and 10 immature specimens, rice paddy in Hotaka, Azumino City, Nagano Prefecture, 3 Aug. 2007. 1 immature specimen, off Hayasaki, Lake Biwa, Shiga Prefecture (33 m in depth), 29 Sep. 1992. 3 immature specimens, off Wani, L. Biwa, Shiga Prefecture, 13 Apr. 1993. 2 immature specimens, Zeze Park, Otsu City, Shiga Prefecture, 9 July, 1999. 10 mature and 14 immature specimens, rice paddy in Hiruta, Yasu City, Shiga Prefecture, 1 June 2009, coll. M. J. Grygier. 4 immature specimens, Ukasho, Yasuki City, Shimane Prefecture, 2 Mar. 2015, coll. N. Kado. 1 immature specimen, rice paddy in Nangoku City, Kochi Prefecture, 24 Mar 2007. 1 immature specimen, Isahaya Bay, Saga Prefecture, 11 Dec. 2000, coll. M. Azuma. Altogether 191 mature and 357 immature specimens from Japan. China: 1 immature specimen, offshore Lake Erhai, Yunnan Province, 13 May 1992, coll. M. Nishino. U. S. A.: 2 immature specimens, Oregon, U. S. A. (detailed collection data unknown), coll. R. O. Brinkhurst. 12 immature specimens, Yakima River, Washington (detailed locality unknown), 29 Oct. 1987, coll. S. V. Fend. 8 mature specimens, Tuolumne River, San Joaquin, California, coll. S. V. Fend. Russia: 2 immature specimens, a nameless stream near Khabarovsk in the tributary of Amur River, 20 Sep. 1992.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFCBE14AFF35F8C790D60DE2.taxon	description	Description. In fixed state, body length 10 – 13 mm, width 0.28 mm at middle of body, with up to 130 segments. Posterior 1 / 7 – 1 / 8 of body without chaetae and unsegmented, with many transverse furrows. Prostomium bluntly conical: length less than half of the width in segment I. Body wall 15 – 25 µm thick, uneven, with several transverse furrows in each segment. Pharynx in II and III, dorsal wall up to 50 µm thick, much thicker than ventral wall. Pharyngeal glands weakly developed. Intestine with thin wall, and with spacious cavity in middle and posterior segments. Chloragogen cells less than 15 µm in height from VI on, a thin layer on gut. Transverse vessels forming complicated loops in II – VII, thick in VIII and IX as hearts (Fig. 1 E). Chaetae all bifid crotchets; the form, size and number not different between dorsal and ventral bundles. In several anterior segments, chaetae (Fig. 1 A) up to 9 per bundle, 41 – 50 µm long, slightly shorter, thicker and more strongly curved than those in the remaining segments; nodulus situated distal to midpoint, and distal teeth parallel: upper tooth about half as long as, and much thinner than lower one. From VII or VIII on, chaetae up to 7 per bundle, 43 – 58 µm long, with nodulus at 1 / 3 or less from distal end, distal ends with lateral wings (Fig. 1 B, C); distal teeth parallel, with upper tooth more than half as long as and much thinner than the lower one. Lateral wings on chaetae made up by lateral expansions along the axis on the convex side of chaeta (Fig. 1 D), extending from slightly distal to nodulus to base of the upper tooth. Maximum width of lateral wings 2.4 – 2.9 µm. Dorsal and ventral chaetae in II and III often fewer (2 or 3 per bundle) than those in later segments. Ventral chaetae in genital segments not modified. Clitellum surround the segments from 1 / 2 VI to end of VIII; the genital segments longer than the rest. Testes two pairs, in V and VI; latter pair larger than the former, and ovaries one pair in VII (Fig. 1 F). Male funnels small, 50 µm in diameter. Vasa deferentia about 200 µm long and 30 µm wide, winding in the middle course, connected with atria apically. Atria stoutly tubular, 130 µm long by 60 µm wide; the inner epithelium tall and glandular. Prostate glands large, connected with atria laterally through a short stalk. Ejaculatory ducts not detected. Penes large in deep and folded chambers (Fig. 1 F), which open separately, just lateral to ventral chaetal bundles in VII. Spermathecae in VI, opening laterally and anterior to the dorsal chaetal bundles (Fig. 1 F); ampullae ovoid and ducts short. Loose sperm found in the ampullae. Sperm sac in V – VII. Egg sac in VI – VII. Making a tight tube from detritus together with mucus secreted from the body wall. Body not coiled up when a live worm is removed from mud tube and stimulated. Cocoon spindle to ovoid in shape, 520 – 600 µm long by 300 – 400 µm wide, covered with fine mineral particles (Fig. 2 A). Operculae of cocoon 40 – 60 µm in diameter, dis- tinct on one end of the long axis, but somewhat inconspicuous in the opposite one. The cocoons invariably contain a single embryo which occupies the whole volume of the cocoon (Fig. 2 B).	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFCBE14AFF35F8C790D60DE2.taxon	discussion	Remarks. This species was distinguished by the absence of hair chaetae and presence of prominent lateral wings on the bifid chaetae. The form of male reproductive organs in the present specimens agrees with the descriptions by Hrabě (1981), Giani et al. (1984) and Finogenova & Arkhipova (1994).	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFCBE14AFF35F8C790D60DE2.taxon	distribution	Distribution. This is a cosmopolitan species (Brinkhurst 1971). In Japan it is common in lakes and ponds, especially shallow waters. These are often the most abundant oligochaetes in paddy fields in Japan (Ohtaka 2018 b).	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFCEE148FF35FB2E94B90921.taxon	description	(Figures 3, 4)	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFCEE148FF35FB2E94B90921.taxon	materials_examined	Material examined. Japan: 1 mature specimen, a spring-fed stream in the Hokkaido National Agricultural Experiment Station, Tsukisamu, Sapporo City, Hokkaido, 9 July 1983. Two immature specimens, spring-fed Ushiwatari stream on Mt. Chokai, Yuza Town, Yamagata Prefecture, 29 July 2015. 5 immature specimens, a brook in Ozegahara Mire, Gunma Prefecture, 8 May 1998. North America: 3 immature specimens, Coeur d’Alene Lake, Idaho, 24 June 2004, coll. J. Kuwabara (S. V. Fend collection).	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFCEE148FF35FB2E94B90921.taxon	description	Description of Japanese material. A live (incomplete) individual 20 mm long and 0.38 mm wide in preclitellar segments, segments 42 +. Body light red when living. Prostomium conical (Fig. 3 F). No distinct secondary annulations. Pharynx in II – III, covered with a thin layer of pharyngeal glands. Chloragogen cells from VI on, thinly covering gut. No stomachal dilatation. Transverse blood vessels forming loops in II – VII, thick in VIII and IX. Individuals living in soft mud tube with adherent foreign matter. Chaetae all crotchets, with form, size and number not different between dorsal and ventral bundles. Those in anterior segments (II – V or II – VI, Fig. 3 A – C) slightly longer than the following ones, 7 – 9 per bundle, 80 – 94 µm long, with distal nodulus and with rudimentary upper tooth or simple pointed distal end; those from VI or VII on (Fig. 3 D, E) 4 – 6 per bundle, 48 – 62 µm long. Nodulus at 1 / 3 from distal end, and distal end brush-like with a series of teeth gradually decreasing in size from lower to upper (Fig. 4 A, B). No lateral expansions in the chaetal shafts in any segments. No modified genital chaetae. Clitellum surround the segments from beginning of X to end of XII, with the wall 16 – 30 µm thick. Gonads and copulatory organs paired (Fig. 3 G). Testes and ovaries attached respectively to posterior sides of septa 9 / 10 and 10 / 11. Male funnels large. Vasa deferentia short and not winding, 240 µm long and 20 µm wide, connected to apical end of atrium. Atria bean-shaped, 150 µm long and 80 µm in maximum diameter. Prostate glands as large as atria. Ejaculatory ducts not detected. Penes 90 µm long, 20 µm wide, two-layered with ordinary cuticular covering, and separate openings lateral to ventral chaetal line at middle of XI. Spermathecae in X, small (Fig. 3 G); ampullae ovoid in shape, 70 µm long and 45 µm wide; ducts stout and well-marked off from the ampullae, about 100 µm long, 20 – 25 µm wide, opening laterally at middle of X. Sperm sac in X. Egg sac observed to extend as far back as XII.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFCEE148FF35FB2E94B90921.taxon	discussion	Remarks. All essential characteristics of the present Japanese material agree well with the original description (Brinkhurst & Cook 1966), the only account prior to this paper (subsequent accounts summarize data of the original description). Spermathecae were " not observed " (Brinkhurst & Cook 1966: 19) in the original material, whereas the single sexually mature Japanese specimen available to us had one pair of spermathecae. The spermathecal ampullae of the present material were small, but they contained sperm masses (Fig. 3 G) and hence can be considered as completely formed. Occasional absence of spermathecae has been observed in other tubificines, for example, in Tubifex tubifex, Ilyodrilus templetoni (Brinkhurst 1971) and in Teneridrilus mastix (Brinkhurst 1978), and absence of spermathecae may be an intraspecific variation also in this species. Furthermore, Brinkhurst & Cook (1966) described eversible pseudopenes in the original description of Aulodrilus americanus, however, the present new material has true penes as defined by Baker and Brinkhurst (1981), because they are two-layered, solid structures, composed of the wall of the penial sac and end of the atrial wall, and have cuticular coverings The segmental position of the genital organs in A. americanus was not originally described, but the present specimen has genital organs located int the normal position of Tubificinae (male pores and spermathecal pores in XI and X, respectively). Unlike many other Aulodrilus species, extra testes were not found in the present specimen. Liang et al. (1998) showed no split of distal ends of chaetae and depicted a membrane between short upper and long lower teeth of chaetae from X on in their Aulodrilus americanus from China. The brush-like form of chaetae in A. americanus can be recognized in observation without high magnifications, and such chaetae appear from VI or VII. A. americanus reported by Liang et al. (1998) might not be A. americanus. The taxonomic position of their A. americanus should be considered provisional until the segmental location and accurate structure of the different types of chaetae has been reinvestigated in the reference material.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFCEE148FF35FB2E94B90921.taxon	distribution	Distribution. This species has been recorded in North America (Brinkhurst & Cook 1966; Brinkhurst 1967, 1978; Hiltunen 1967, 1969; Stimpson et al. 1975; Spencer 1980) and in Japan (Ohtaka, unpublished data in Timm 1999 a), showing circum-Pacific distribution (Timm 1999 a). These records are formally the first of this species in Japan. The Japanese habitats were cool waters, including spring-fed streams in Sapporo (water temperature 10.5 ° C), Ushiwatari stream in Yuza Town (12.3 ° C), and a brook in a sphagnum bog of Ozegahara Mire, Gunma Prefecture. Differing from many other Aulodrilus species living in warm waters, the preference of A. americanus for cool-water habitats is apparently unique.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFCCE146FF35FA1E96050D9D.taxon	description	(Figure 5)	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFCCE146FF35FA1E96050D9D.taxon	materials_examined	Material examined. Japan: 1 immature specimen, Lake Hiyamizu-numa, Tsugaru City, Aomori Prefecture, 16 July. 2005. 5 immature specimens, Takahamairi Bay, Lake Kasumigaura, Ibaraki Prefecture, 9 Feb. 2011. 2 immature specimens, offshore Lake Inba-numa, Chiba Prefecture, 9 Mar. 2009. 2 immature specimens, Lake Nishi-no-ko near Lake Biwa, Ohmi-Hachiman City, Shiga Prefecture, 8 Aug. 2001. 1 immature specimen, Pond Otome-ga-ike near Lake Biwa, Takashima City, Shiga Prefecture, 19 Mar. 2002. 3 immature specimens, Pond Sone-numa near Lake Biwa, Hikone City, Shige Prefecture, 12 Dec. 2001, 11 Mar. 2002. 1 immature specimens, littoral Lake Biwa, Shiga Prefecture, 14 Feb. 1994. 1 immature specimen, rice paddy, Izumo City, Shimane Prefecture, 24 July 2015. U. S. A.: USNM 58782, an immature specimen, Cayuga Lake, New York, 20 May, 1974, coll. D. R. Spencer. Russia: 5 mature and 15 immature specimens, Rybinsk Reservoir on the Middle Volga River, coll. N. R. Arkhipova; cultured at the Võrtsjärv Limnological Station, Estonia by T. Timm since 1987 and sampled in 11 Oct. 2006.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFCCE146FF35FA1E96050D9D.taxon	description	Description. All of the Japanese specimens were immature; identified mainly based on the chaetal morphology. Chaetal characteristics in Japanese specimens as follows: Dorsal chaetal bundles consisting of hair and bifid crotchets, both beginning in II. Hair chaetae (Fig. 5 A) smooth and slightly sigmoid in shape, 3 – 8 per bundle, 160 – 256 µm long in anterior segments, 0 – 4 per bundle, 144 – 173 µm long in posterior segments. Dorsal crotchets (Fig. 5 B, C) with nodulus situated at 1 / 3 – 1 / 4 from distal ends, 6 – 8 per bundle, 64 – 104 µm long in anterior segments, 3 – 5 per bundle, 56 – 80 µm long in posterior segments; distal teeth weakly divergent with upper tooth 1 / 2 – 2 / 3 as long as and thinner than lower tooth (Fig. 5 E, F). Ventral chaetae (Fig. 5 D) bifid crotchets with nodulus situated at 1 / 3 – 1 / 4 from distal ends, 10 – 15 per bundle, 64 – 80 µm long in anterior segments, 5 – 8 per bundle, 56 – 67 µm long in posterior segments; distal teeth parallel, and upper tooth shorter and thinner than lower. Shafts of both dorsal and ventral crotchets slightly widened laterally beneath distal teeth (Fig. 5 G). Mature specimens from Russia have the atrial segment (VII) swollen laterally, with male pores opening at the ventral side of the right and left expansion (Fig. 5 H). Vasa deferentia 340 µm long, longer than atria. Atria crescentshaped, 260 µm long, 60 – 80 µm wide, receiving a petiolate prostate gland at concave side (Fig. 5 I). Ejaculatory ducts short and muscular, leading to conical penes. Spermathecae with short ducts and large saccular ampullae, opening on lateral sides in VI (Fig. 5 I). Alimentary canals with thin chloragogen cells from VII on, widening abruptly in VIII or IX (Fig. 5 H).	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFCCE146FF35FA1E96050D9D.taxon	discussion	Remarks. Aulodrilus pluriseta is distinguishable from congeners by having dorsal hairs from II and bifid chaetae with upper teeth shorter and thinner than lower teeth. Crescent-shaped or oval atria, short ejaculatory ducts and conical penes found in the present Russian specimens agree with earlier descriptions by Hrabě (1981), Giani et al. (1984), and Finogenova & Arkhipova (1994). Spermathecae consisting of a large saccular ampullae and short ducts opening laterally in the present Russian material also coincide with an earlier description by Finogenova & Arkhipova (1994). By contrast, Giani et al. (1984: Fig. 2 b) described tubular spermathecal ampullae in their A. pluriseta. Aiyer (1925) described narrow and elongate spermathecal ampullae in A. trivandranus, a species that has been synonymized with A. pluriseta by Brinkhurst (1971). The differences in the shape of spermathecal ampullae might indicate that nominal A. pluriseta consists of more than one species, but it is also probable that spermathecal ampullae change in form and size depending on the degree of maturation or the volume of sperm received. Aulodrilus sp. reported by Brinkhurst et al. (1990) from Guandong and Shandong Provinces in China resembles A. pluriseta in having hair and bifid chaetae in dorsal bundles. However, the distal teeth of anterior dorsal chaetae in the Aulodrilus sp. have equal length and thickness. The species is different from A. pluriseta, in which the upper teeth of dorsal chaetae are invariably shorter and thinner than the lower teeth. In addition, the Aulodrilus sp. has unique long, coiled, and heavily muscular spermathecal ducts, which are not found in any other congener. It is probable that this material represents a distinct undescribed species.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFC2E142FF35FDD096760EA5.taxon	description	(Figures 6, 7, 8)	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFC2E142FF35FDD096760EA5.taxon	materials_examined	Material examined. Japan: 20 immature specimens, a pond in Wakkasakanai, Toyotomi Town, Hokkaido, 29 Oct. 1984. 2 immature specimens, Shinoro-Shinkawa River, Sapporo, Hokkaido, 6 May 1983. 128 mature and 500 immature specimens, Maruyama, Sapporo City, Hokkaido, 4, 19 Oct., 30 Dec. 1983; 23 Apr., 18 May, 2, 28 July, 15 Aug. 12 Oct., 4 Nov. 1984; 19 Apr. 10 May, 20 June, 27 July, 11, 28 Aug., 19 Sep., 1985. 6 immature specimens, Nishioka reservoir, Sapporo City, Hokkaido, 1 Sep. 1982, 28 Apr. 1983. 2 mature and 7 immature specimens, littoral Lake Shikotsu, Hokkaido, 30 May 1979, coll. T. Ito. 2 immature specimens, littoral Lake O-numa, Nanae Town, Hokkaido, 9 May 1984. 5 immature specimens, Mitake Park, Hirosaki City, Aomori Prefecture, 17 July 1992. 3 immature specimens, a stream in Tokiwano, Hirosaki City, Aomori Prefecture, 15 May 2009. 20 immature specimens, rice paddy in Sakamoto, Hirosaki City, Aomori Prefecture, 16 July, 25 Sep. 2011; 1 Sep. 2012. 10 immature specimens, Osawa near Lake Tazawa, Senboku City, Akita Prefecture, 29 Sep. 2007. 1 immature specimen, Ushiawari River on Mt. Chokai, Yuza Town, Yamagata Prefecture, 29 July 2015.1 immature specimen, a brook in Gobono, Obanazawa City, Yamagata Prefecture, 8 May 1984. 1 immature specimen, a stream in Naganeyama hill, Obanazawa City, Yamagata Prefecture, 9 Aug. 1990. 3 immature specimens, offshore Lake Onogawa, Kita-Shiobara Village, Fukushima Prefecture (2.5 m depth), 9 July, 2010. 1 immature specimen, offshore Lake Yunoko, Nikko City, Tochigi Prefecture (6 m in depth), 22 July 1988, coll. T. Iwakuma. 3 immature specimens, offshore Lake Maru-numa, Katashina Village, Gunma Prefecture (16.3 m depth), 21 Sep. 2009. 6 immature specimens, Saikawa River, Sano City, Tochigi Prefecture, 10 Nov. 1980. 3 immature specimens, River Takada, Tomioka City, Gunma Prefecture, 4 Apr. 1984. 5 immature specimens, littoral Lake Kizaki, Omachi City, Nagano Prefecture (5.3 m depth), 2 Aug. 2007. 4 immature specimens, Tsuya River, Yoro Town, Gifu Prefecture, 9 June 2005, coll. K. Tanida. 15 immature specimens, north basin of Lake Biwa (10 – 70 m deep, mud), 26 Jan. 1992 – 14 Feb. 1995. 7 immature specimens, a marsh in Hayasaki, Nagahama City, Shiga Prefecture, 29 Aug. 2002. 2 immature specimens, Mizorogaike Marsh, Kyoto City, Kyoto Prefecture, 1 Nov. 2004, coll. Y. Murakami. 10 immature specimens, Kitafune Stream, Izumo City, Shimane Prefecture, 6 Nov. 1993. 5 immature specimens, Rivers Kanna and Kesashi, Okinawa Is., Okinawa Prefecture, 7, 8 Aug. 1990, coll. M. Tsuchiya. Altogether 130 mature and 642 immature specimens from Japan. Taiwan: 1 immature specimen (ESRI-OA 0009), a pond in Minchien, Nantou County, 10 Sep. 2008. U. K.: 1 mature and 3 immature specimens, Bala Lake, N. Wales, 1962 (detailed collection data unknown), (R. O. Brinkhurst collection). Estonia: 25 immature specimens, aquarial culture at the Võrtsjärv Limnological Station, started in 2006 with specimens from the Emajõgi River, Tartu City, Estonia, coll. T. Timm. U. S. A. USNM 32648, 1 immature specimen from Sonoma County, California, 18 Sep. 1962, R. O. Brinkhurst collected and deposited as Aulodrilus pluriseta. 2 mature and 1 immature specimens, Santa Clara, California (exact locality unknown), 1 Apr. 2002, coll. S. V. Fend. 10 immature specimens, a stream near McMinnville, Oregon, 10 May, 2001, coll. S. V. Fend. 3 immature specimens, Coeur d’Alene Lake, Idaho, 24 June 2004, coll. J. Kuwabara (S. V. Fend collection). 5 immature specimens, Sacra- mento – San Joaquin River Delta, California, Oct. 2003, coll. W. Fields. 2 immature specimens, Cosumnes River, San Francisco Bay Delta, California (date and collector unknown) (S. V. Fend collection).	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFC2E142FF35FDD096760EA5.taxon	description	Description. The following description is based on the topotypic specimens from Maruyama, Sapporo, Japan. Mature and living state: length 28 – 35 mm, width 0.3 – 0.5 mm in anterior segments; up to 150 segments. Body anteriorly dark red; posteriorly somewhat yellowish. Prostomium conical, more or less pointed. No secondary annulations. Posterior part of body (consisting of up to 45 segments) without chaetae, and the posterior end of about 0.4 mm without septa, loosely packed with coelomocytes. Pharynx in II and III; thick walls (20 – 25 µm) covered by a thin layer of pharyngeal glands. Chloragogen cells from posterior part of IV on, a thin tissue as far as VIII or IX, and then suddenly thickened. Intestine widens at X or XI. Contractile commissural vessels in VIII – IX. Dorsal vessel shifted ventrolaterally in X, located on the left side of ventral vessel. Nephridia from XI, elongate; ental part of narrow duct densely surrounded by large (up to 80 µm diameter) and spherical cells. Forming a loose and thick mud tube. Dorsal chaetal bundles consisting of hair and pectinate crotchets, both beginning in II. Hair chaetae smooth and slightly sigmoid, 4 – 7 per bundle, 90 – 207 µm long in anterior segments; 1 – 3 per bundle, 60 – 150 µm long in posterior ones. Dorsal crotchets (Fig. 6 A) with distal nodulus, 5 – 9 per bundle, 76 – 110 µm long in anterior segments; 2 – 6 per bundle, 65 – 86 µm long in posterior ones; distal end with upper tooth split into 5 – 20 fine teeth which are arranged irregularly, and much thinner and shorter than single lower tooth (Fig. 6 D, E, G, H). Ventral chaetae (Fig. 6 B, C) bifid crotchets with distal nodulus, 8 – 13 per bundle, 75 – 112 µm long in anterior segments; 3 – 8 per bundle, 68 – 84 µm long in posterior segments; distal teeth parallel and lower tooth about twice longer and much thicker than upper one; one to several small teeth often occur laterally between upper and lower teeth (Fig. 6 F). Distal parts of all dorsal and ventral crotchets with lateral expansions along the axis of chaeta. Ventral chaetae in spermathecal and penial segments of usual type, neither modified nor absent even in fully mature specimens. Clitellum more or less conspicuous, usually occupying from 2 / 3 IX to end of XI; ventral side flattened and slightly swollen laterally of male pores. Gonads and copulatory organs paired (Fig. 7 A). Testes usually in VIII and IX, ovaries in X. In fully mature specimens, anterior pair of testes not as well developed as posterior testes and ovaries. Male funnels one pair on 9 / 10, large, 160 µm in diameter. Vasa deferentia about 600 µm long, winding and slightly stouter ectally than entally, connected with atrium apically. Atrium bean-shaped, 180 – 220 µm long, inner epithelium thick and glandular with basal nuclei (Fig. 7 B). Prostate gland large, connected laterally with atrium through short and narrow stalk (Fig. 7 C). Ejaculatory duct about 190 µm long, nearly as long as atrium, and swollen at middle (Fig. 7 B). Penes short and conical, set in small depressed chambers, opening at lateral side of ventral chaetal bundle in X or rarely XI (Fig. 8 B). Paired spermathecae usually in VIII and IX (Fig. 7 A); anterior pair smaller than posterior one. Spermathecal ampullae globular or ovoid in shape. Spermathecal ducts short, well-marked off from ampullae, opening laterally at slightly behind anterior septa (Fig. 8 A). Loose sperm masses present in spermathecal ampullae. Sperm sac usually in VIII – X. Egg sac restricted to ovarial segment. Variation. Variations related to multiplication of spermathecae and to shift in the segmental position of genital organs were found in the present specimens as follows. Of 28 mature specimens from the type locality in Sapporo, 24 had two pairs of spermathecae, one in VIII and another one in IX, and one pair of male ducts in X (Fig. 8 C). One specimen showed the same arrangement of genital organs, but lacked the spermatheca on the left side in VIII. Two specimens had a third pair of spermathecae in VII, in addition to those in VIII and IX (Fig. 8 D). One specimen had paired spermathecae in VII, IX, and X and the male duct in XI. In all cases examined, anterior spermathecal ampullae were smaller than posterior ones.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFC2E142FF35FDD096760EA5.taxon	discussion	Remarks. Since Yamaguchi (1953) described the present species based on immature specimens lacking genital organs except for gonads, the identity of this species has remained unclear for several decades (Brinkhurst 1963, 1971; Brinkhurst & Wetzel 1984). Brinkhurst (1971) once tentatively synonymized it with A. pluriseta (Piguet). Hrabě (1981) described the male duct for the first time and regarded A. japonicus as a distinct species. Then Finogenova & Arkhipova (1994), Liang & Xie (1997), and Timm & Všivkova (2007) redescribed the species based on specimens from continental Eurasia. The newly obtained Japanese specimens, including topotypes listed above, agree well with the previous descriptions both in chaetal and genital structures. A. japonicus differs from A. pluriseta in the following respects (corresponding condition of latter species in parentheses): upper teeth multiple in dorsal crotchets (both dorsal and ventral crotchets mostly bifid); vasa deferentia about three times longer than atria (slightly longer than atria); male ejaculatory ducts long, as long as atria (much shorter than atria); spermathecal ampullae ovoid, well distinguished from ducts (cylindrical and not well marked off from the ducts); wide midgut begins either in X or XI (VIII or IX); very thick chloragogen tissue appears in one segment before the beginning of midgut (chloragogen tissue thin throughout). Results of this examination confirmed that all specimens listed above have multiple upper teeth in the dorsal chaetae. The irregularly arranged, multiple upper teeth in the dorsal chaetae of A. japonicus are unique in oligochaetes, whereas such a condition is common in hooded hooks of capitellid polychaetes (e. g., Yabe & Mawatari 1998; Tomioka et al. 2016). Additional small teeth were often found in ventral chaetae on the lateral sides on the base of teeth branch in the SEM observation of topotypic specimens (Fig. 6 F). Finogenova & Arkhipova (1994) presented this structure on Neva estuary specimens from western Russia. All mature Japanese specimens that were examined had more than one pair of spermathecae. Two pairs of spermathecae in VIII and IX are also confirmed in the Bala Lake specimen from northern Wales and in a Santa Clara specimen from North America. Multiple pairs of spermathecae, in VIII and IX and occasionally also in VI, were described for Czech material (Hrabě 1981) and for Chinese specimens (Liang & Xie 1997). Multiple pairs of spermathecae therefore appear to be the normal condition in A. japonicus. The long ejaculatory duct with a middle swelling is also unique in the genus. Gonads were found in VIII, IX, and X in the present specimens, as Yamaguchi (1953) described. In fully mature worms, gonads of IX (testes) and X (ovaries) were well developed, although those in VIII (testes) were rudimentary. The rudimentary testes were much smaller and without corresponding efferent ducts. They are thought to be functionless as in A. pluriseta (Naidu 1965), A. remex Stephenson, 1923 (Aiyer 1929), (a synonym of A. pigueti), and A. pigueti (present study).	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFC2E142FF35FDD096760EA5.taxon	distribution	Distribution. Widespread. This species has been confused with A. pluriseta. For example, A. pluriseta of Wang & Liang (2001) should be ascribed to A. japonicus. USNM 32648, a California specimen registered as A. pluriseta, is confirmed to be A. japonicus in the present study. This is a common tubificine, at least in Japanese waters. Periodic samplings at a small, shallow pond in Maruyama, Sapporo (type locality) revealed that mature individuals of the present species appeared — in a low proportion (maximum 10 %) — only during summer when water temperature was above 15 ° C (Ohtaka, unpublished data). Van den Hoek & Verdonschot (2005) also noted that mature specimens of A. japonicus were found only in July in the Netherlands.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFC6E141FF35FC8891C40E98.taxon	description	(Figures 9, 10)	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFC6E141FF35FC8891C40E98.taxon	materials_examined	Holotype. NSMT-An 625, a mature specimen, 22 June 1982, coll. H. Kikuchi. Anterior part of the body sagittally sectioned and mounted on two slides and the posterior one whole-mounted on another slide. Type locality. Offshore Lake Kitaura, Ibaraki Prefecture, Japan (36.016 N, 140.566 E), 6 m deep with muddy bottom. Paratypes. NSMT-An 626, a cross-sectioned mature specimen from the type locality on one slide, 16 July 1982, coll. H. Kikuchi; NSMT-An 627, a whole-mounted mature specimen from the type locality, 22 June, 1982, coll. H. Kikuchi. Other material examined. Japan: 3 immature specimens, offshore Lake Toro, Shibecha Town, Hokkaido, 6 June 2000, coll. T. Ito. 5 mature and 20 immature specimens, offshore Lake Takkobu, Kushiro City, Hokkaido, 23 July 2003, coll. T. Ito. 6 immature specimens, littoral Lake Barato, Sapporo City, Hokkaido, 12 Oct. 1983. 5 immature specimens, littoral Lake Ogawara, Kamikita Town, Aomori Prefecture, 21 Sep. 2003. 2 immature specimens, offshore Lake Hachiro-gata, Akita Prefecture (3.6 m depth), 9 July, 2005. 1 immature specimen, offshore Lake Izunuma, Tome City, Miyagi Prefecture, 7 June 2008. 42 mature and 87 immature specimens, offshore Lake Kitaura (type locality), 29 May, 14 June, 3 July 1980; 28 Oct., 20 Nov., 26 Dec. 1981, 16 Mar. 1982; 19 Apr., 20 May, 22 June, 16 July, 26 Aug., 29 Sep., 26 Nov. 1982; 14 Apr., 17 May, 25 June, 14 July, 3 Aug., 15 Dec. 1983; 14 Feb., 18 May, 14 June, 16 July, 17 Aug., 14 Sep. 1984; 5 Jan. 1985. 3 immature specimens, Mizuhara, Lake Kitaura, Ibaraki Prefecture, July 1981. 10 immature specimens, offshore Lake Kasumigaura, Ibaraki Prefecture, 10 Jan. 1984; 9 Oct. 1985; 9 Feb. 2011, coll. T. Iwakuma. 3 immature specimens, offshore Lake Inba-numa, Chiba Prefecture, 9 Mar. 2009. 3 mature and 2 immature specimens, offshore Lake Kahoku-gata, Ishikawa Prefecture, 11 Aug. 1999, coll. M. Nishino. 2 mature and 4 immature specimens, offshore Lake Suwa, Nagano Prefecture, 18 Oct. 1980. 2 immature specimens, offshore Lake Yogo, Nagahama City, Shiga Prefecture, 7 May 2000, coll. M. Nishino. 8 immature specimens, offshore Lake Koyama-ike, Torrori City Torrori Prefecture, 16 Mar. 2010. 2 immature specimens, Kanna Reservoir, Ginoza Village, Okinawa Island, Okinawa Prefecture, 14 May 2018, collector unknown. Altogether 55 mature and 158 immature specimens.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFC6E141FF35FC8891C40E98.taxon	etymology	Etymology. The specific epithet refers to the form of the distal ends of the dorsal chaetae, having several teeth.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFC6E141FF35FC8891C40E98.taxon	description	Description. In fixed state, length 10 – 20 mm, maximum width 0.36 mm in clitellum, 0.2 – 0.27 mm in mid-segments; 85 – 125 segments. Prostomium bluntly conical. Posterior segments (less than 1 / 10 of body length) without chaetae. No secondary annulation, but many narrow transverse furrows present. In anterior segments, epidermis 13 – 20 µm thick with many glandular cells staining deeply with hematoxylin. Pharynx in II and III; pharyngeal glands weakly developed dorsally (Fig. 10 A). Chloragogen cells from VII, 5 – 10 µm in height, thinly covering gut. Intestine more or less widening in VII. Clusters of pear-shaped cells, 20 – 30 µm in height, present around ventral nerve cord in III – V. Transverse vessels forming loops in II – V. All dorsal chaetal bundles, beginning in II, with hairs and crotchets. Hairs smooth, slightly sigmoid, about twice as long as crotchets in the same respective bundles; 5 – 8 per bundle, 150 – 172 µm long in anterior segments and 2 – 5 per bundle, 104 – 130 µm long in posterior segments. Dorsal crotchets (Fig. 9 A – C) weakly sigmoid in shape with distal nodulus; 7 – 8 per bundle, 60 – 68 µm long in anterior segments, 2 – 5 per bundle, 50 – 64 µm long in posterior ones. Distal end of dorsal crotchets bifid or divided into several fine and blunt teeth. In some anterior bundles (mostly II and III), distal teeth frequently bifid (Fig. 9 E) or pectinate with long lateral teeth and short intermediate teeth (Fig. 9 F). In mid-segments, several (4 – 8) digitiform teeth arranged in a single row, showing pectinate condition (Fig. 9 G, H, L, M). Distal teeth often rudimentary in posterior bundles (Fig. 9 I, J). Ventral chaetae (Fig. 9 D) all bifid crotchets with nodulus slightly distal to middle: 9 – 15 per bundle, 58 – 68 µm long in anterior segments and 2 – 10 per bundle, 50 – 60 µm long in posterior ones; upper tooth of the ventral crotchets about half as long as and slightly thinner than lower ones (Fig. 9 K). No lateral expansion on dorsal or ventral crotchets. In sexually mature specimens, ventral chaetae in VII (segment having male pore) not modified but reduced in number or absent. Clitellum from 1 / 2 VI to end of VIII, conspicuous, broadly flattened ventrally; epidermis thick (up to 30 µm) and glandular. Gonads and copulatory organs (Fig. 10 A, B) paired. Testes and ovaries paired respectively in VI and VII. Additional testes sometimes in V (Fig. 10 A). Male funnels not large. Vasa deferentia about 260 µm long, not winding, connected with atria apically. Atria stoutly tubular in shape, 220 µm long, 80 µm wide, with high and glandular inner epithelium (Fig. 10 B, E). Prostate gland large and solid, laterally connected to atrium by narrow (18 µm wide) junction (Fig. 10 F). Ejaculatory ducts not detected. Penes rounded conical in shape, set in spacious copulatory bursa (Fig. 10 B), opening ventrolaterally near middle of VII, immediately anterior to the chaetal bundle (Fig. 10 D). Spermathecae in VI, opening ventrolaterally at mid-segment (Fig. 10 B, C); ampullae large, globular or ovoid, 120 – 220 µm in diameter, containing 3 – 7 loose sperm masses; spermathecal ducts 30 – 50 µm long, short but well-defined from ampullae. Sperm sac in VI and VII. Egg sac in VII and VIII.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFC6E141FF35FC8891C40E98.taxon	discussion	Remarks. Aulodrilus dentosus sp. nov. resembles A. pluriseta, A. japonicus or A. apeniatus in having hair chaetae beginning in II and pectinate chaetae in the dorsal bundles, but it is clearly distinguished from the congeners in having dorsal crotchets with multiple digitiform teeth of similar length and arranged in one direction. In contrast, distal ends of dorsal crotchets are bifid in A. pluriseta, with multiple upper teeth in A. japonicus, and with fine intermediate teeth between upper and lower teeth in A. apeniatus. As to the distal shape of the dorsal crotchets, the present species more closely resembles A. pectinatus. However, the present species has no modified genital chaetae. Its hair chaetae invariably begin in II, whereas A. pectinatus has spoon-shaped penial chaetae and lacks hair chaetae in II and III (Aiyer 1928; Brinkhurst 1971). Furthermore, the number of distal teeth in dorsal crotchets of A. dentosus sp. nov. (5 – 8) is higher than that of A. pectinatus (usually 2 – 3 and rarely 4) (Aiyer 1928). Structure of male duct of the present species resembles that of A. limnobius in the stoutly tubular atrium, which is slightly shorter than the vas deferens, and directly connected with penis without an ejaculatory duct.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFC6E141FF35FC8891C40E98.taxon	distribution	Distribution. It has been recorded from muddy bottoms in shallow and eutrophic lakes and lagoons in Hokkaido, Honshu, and Okinawa islands in Japan (Ohtaka 2014 under the name of Aulodrilus sp.). Aulodrilus sp. from Lake Hachiro-gata (Ohtaka 2006), from Lake Izu-numa (Ohtaka 2009), from Lake Kitaura (Ohtaka & Kikuchi 1997), from Lake Toro (Ito et al. 2002), from Lake Ogawara (Ohtaka & Sato 2005), from Lake Takkobu (Takamura et al. 2009), and from Lake Inaba-numa (Ohtaka et al. 2010) correspond to this species. The localities include both freshwater and brackish habitats. The present species can withstand salinity to some degree.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFC5E15FFF35FCD491EE0D9C.taxon	description	(Figures 11, 12)	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFC5E15FFF35FCD491EE0D9C.taxon	materials_examined	Holotype. NSMT-An 628, a mature specimen, 20 July 1984, the anterior part of body sagittally sectioned and mounted on one slide and the posterior one whole-mounted on another slide. Type locality. Paddy field in Takasaki City, Gunma Prefecture, Japan (36.361 N, 138.956 E). Paratypes. Paratypes. NSMT-An 629, a whole-mounted specimen; NSMT-An 630, a cross-sectioned specimen; locality and date the same as for the holotype. Other material examined. Japan: 10 mature and 2 immature specimens, paddy field in Takasaki City, Gunma Prefecture (type locality), 20 July 1984. 7 mature and 5 immature specimens, paddy field in Gunma Town, Gunma Prefecture, 20 July 1984. 1 mature and 7 immature specimens, paddy field in Tomioka City, Gunma Prefecture, 16 Aug. 1985, 13 Aug. 2017. One mature specimen, paddy field in Izumo City, Shimane Prefecture, 24 July 2015, coll. N. Kado.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFC5E15FFF35FCD491EE0D9C.taxon	etymology	Etymology. The specific epithet refers to the summers during which all the specimens examined were collected.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFC5E15FFF35FCD491EE0D9C.taxon	description	Description. Fixed mature specimens: 8 – 15 mm length, 0.20 – 0.35 mm width, and 45 – 80 segments. Posterior end of 0.2 – 0.5 mm in length without septa, devoid of chaetae. Prostomium almost absent (Fig. 11 B, C). Epidermis 6 – 10 µm thick, with glandular cells dense in anterior part. Pharynx in II and III, pharyngeal glands weakly developed (Fig. 11 C). Alimentary canal abruptly widening in VIII or IX. Chloragogen cells from VII on, covering gut thinly. Intestinal wall thin in middle and posterior segments. Transverse vessels form loops in II – VI; thick in VII and VIII as hearts (Fig. 11 B). Living animals in loose mud tube with mucus and foreign matter. Dorsal chaetal bundles consist of short hairs and bifid crotchets. Dorsal hairs beginning in either of IV – VIII, smooth and weakly curved (Fig. 11 D); 2 – 6 per bundle, 60 – 90 µm long; the length less than twice that of crotchets in the same respective bundles. Dorsal crotchets in anterior segments (Fig. 11 E) 4 – 13 per bundle and 42 – 62 µm long, with nodulus slightly distal and with parallel teeth, with the upper tooth 2 / 3 – 1 / 2 times longer and much thinner than the lower (Fig. 11 H, I); those in posterior segments 2 – 5 per bundle and 33 – 44 µm long, more strongly curved, with nodulus situated at 1 / 3 – 1 / 4 from distal end, and lower teeth thickened more than those in anterior segments. Lower tooth of posterior dorsal crotchets sometimes rounded or divided into some short teeth (Fig. 11 J, K). Ventral chaetae (Fig. 11 F, G) all bifid crotchets 5 – 12 per bundle, 44 – 62 µm long in anterior segments; 3 – 7 per bundle, 36 – 42 µm long in posterior ones; distal shape and position of nodulus not different from dorsal crotchets. Number of ventral chaetae decreased in genital segments. No modified genital chaetae. In mature specimens, ventral chaetae in segment with male pore reduced in number or lost completely. No lateral expansions on chaetal shafts in dorsal or ventral chaetae. Clitellum conspicuous, usually extending from chaetal line of IX to slightly behind chaetal line of XI (Fig. 11 A), but often shifted anteriorly from 1 / 2 VI to VIII in accordance with shift of other genital organs. Testes and ovaries paired, usually in IX and X (Fig. 12 A), sometimes in VI and VII, respectively. Male funnels small, 15 – 20 µm in diameter. Vasa deferentia 150 – 200 µm long, hardly winding, connected with atrium apically (Fig. 12 A). Atria crescent-shaped, 120 µm long and 36 µm wide, with high and glandular inner epithelium (Fig. 12 B). Prostate glands about as large as atria, connected to concave side of atria through short stalks. Penes long when protruded, opening close to each other within a large median male bursa situated in middle to posterior 1 / 3 of X (or VII) (Figs. 11 A, 12 A, E). Spermathecae (Fig. 12 C) small, separately opening on small papillae anterior to the chaetae of IX (or VIII) and close to ventral nerve cord (Fig. 12 D). Ampullae ovoid in shape, 35 µm long by 28 µm wide, with the wall 2 – 5 µm thick. Spermathecal ducts 30 µm long with thick wall. Loose sperm in the ampullae. Sperm sac extending anteriorly as far as V, with egg sac as far back as XII, both weakly developed. Variation. Two cases were found in the segmental position of genital organs among specimens examined (Fig. 17): one has testes and spermathecae in IX with ovaries and male pores in X (see description), and the other has testes and spermathecae in VI with ovaries and male pores in VII. Among specimens examined from the type locality (n = 12), the former case (9 individuals) was more frequent than the latter (three individuals). No intermediate conditions between the two cases above have been found there. The clitellum always covered the segments having spermathecae and male pores, but varied in the segmental position in accordance with the position of genital organs. The beginning of dorsal hairs also varied in accordance with the position of the genital organs: The dorsal hairs began in IV, V, or VI in specimens having male pores in VII, and they began in VI, VII or VIII in those having male pores in X.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFC5E15FFF35FCD491EE0D9C.taxon	distribution	Distribution. The present species has hitherto been collected in summer seasons from several inundated paddy fields in central and western parts of Japan. A congener, A. limnobius, has been collected in these localities together with another tubificine, Limnodrilus hoffmeisteri Claparède.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFC5E15FFF35FCD491EE0D9C.taxon	discussion	Remarks. Aulodrilus aestivus sp. nov. is most similar to A. pigueti and A. acutus by the following characteristics: 1) male efferent ducts open into a median male bursa; and 2) dorsal hairs are absent in some anterior segments. However, the present species has neither oar-shaped chaetae nor blade-shaped chaetae in the dorsal bundles, which are characteristic, respectively, of A. pigueti and A. acutus. The crescent-shaped atrium of the present species is also different from the globular atria of A. pigueti and A. acutus. In contrast, the present species resembles A. pluriseta in having hair chaetae and bifid crotchets in dorsal bundles, and crescent-shaped atria. However, in the latter species, dorsal hair chaetae begin in II and male ducts open in line with the ventral chaetae, thus differing from the present species in which hair chaetae begin in IV – VIII and male ducts open into a median male bursa.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFDBE15AFF35FB0196A80F51.taxon	description	(Figures 13, 14)	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFDBE15AFF35FB0196A80F51.taxon	materials_examined	Material examined. Japan: 5 immature specimens, offshore O-numa, Nanae Town, Hokkaido (10 – 12 m depth), 1 June 2008. 3 immature specimens, rice paddy in Iwaihana, Hachimantai City, Iwate Prefecture, 15 July 2007. 3 immature specimens, offshore Lake Izunma, Tome City, Miyagi Prefecture (1.5 m depth), 7 June 2008. 1 immature specimen, Kabukuri-numa Marsh, Tome City, Miyagi Prefecture, 7 June 2008. 3 mature specimens, Nikatsutsumi reservoir, Maki Town, Niigata Prefecture, 7 Oct. 1982. 1 immature specimen, a stream in Saitama City, Saitama Prefecture, Aug. 2005, coll. T. Torii. 2 immature specimens, littoral Lake Hinuma, Ibaraki prefecture, 9 Aug. 1982, coll. H. Morino. 4 mature and 178 immature specimens, offshore Lake Kitaura, Ibaraki Prefecture (6 m depth), 3 July, 9 Aug. 1980, 20 Jan., 20 May, 22 June, 16 July, 26 Aug., 29 Sep., 21 Oct., 19, 26 Nov., 24 Dec. 1982; 24 June, 14 Feb., 15 Mar., 14 Apr., 17 May, 25 June, 14 July, 19 Aug. 1983; 20 Jan., 14 June, 16 July, 17 Aug., 14 Sep. 1984; 17 June 1985. 4 immature specimens, Mizuhara, Lake Kitaura, Ibaraki Prefecture, 11 Dec. 1980; 9 June 1981. 5 immature specimens, offshore Lake Kasumigaura, 9 Aug. 1983, 9 Feb. 2011. 3 mature and 2 immature specimens, offshore Lake Suwa, Nagano Prefecture (5.5 m depth), 18 Oct. 1980; 9 Aug. 2006, coll. H. Fukuhara. 2 immature specimens, Lake Kahoku-gata, Ishikawa Prefecture, 11 Aug. 1999, coll. M. Nishino. 3 immature specimens, Yamanoshita Bay, south basin of Lake Biwa, Otsu City, Shiga Prefecture, 3 Oct. 1992. 2 immature specimens, Mizorogaike Marsh, Kyoto City, Kyoto Prefecture, 1 Nov. 2004, coll. Y. Murakami. 1 immature specimen, River Kitafune, Hirata City, Shimane Prefecture, 6 Nov. 1993. Littoral Lake Ikeda, Ibusuki City, Kagoshima Prefecture (10 m depth), 15 July 1998. Altogether 10 mature and 112 immature specimens from Japan. U. S. A.: 16 immature specimens, Coeur d’Alene Lake, Idaho, 24 June 2004, coll. K. Kuwabara (S. V. Fend collection). 2 immature specimens, Cosumnes River, San Francisco Bay Delta, California, (date and collector unknown) (S. V. Fend collection).	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFDBE15AFF35FB0196A80F51.taxon	description	Description. Description of Japanese specimens in mature and preserved states: 6 – 9 mm length, about 0.25 mm width in anterior segments; up to 62 segments. Posterior 1 / 5 – 1 / 7 of body without chaetae and unsegmented, with numerous transverse wrinkles. Prostomium bluntly conical. Pharynx covered by a thin layer of pharyngeal glands. Intestine suddenly widens in VII. Chloragogen cells on gut from VI or VII on. Transverse vessels forming complicated loops in I – VI. Forming a mud tube with mucus and foreign matter. Dorsal chaetal bundles consist of hairs and bifid or oar-shaped chaetae. Dorsal hairs smooth and slightly sigmoid, beginning in III or IV in immature specimens but in III in mature ones: 2 – 8 per bundle, 70 – 125 µm long. Dorsal crotchets in anterior segments (Fig. 13 A, B) 6 – 11 per bundle, 46 – 80 µm long, with distal nodulus and with upper tooth shorter and thinner than lower one; replaced by 4 – 8 oar-shaped chaetae (Fig. 13 C, D, G – K) from VII to X on. Oar-shaped chaetae 50 – 82 µm long. Distal, oar-shaped part 4.1 – 5.7 µm wide; chaeta with nodulus at 1 / 3 from distal end, bent backward slightly at 1 / 4 from distal end (Fig. 13 D). The distal part rounded and slightly concave with a swollen edge (Fig. 13 C, J, K). Ventral chaetae (Fig. 13 E) all bifid crotchets with nodulus at 1 / 3 from distal end and with parallel teeth, with upper tooth about 2 / 3 times longer and much thinner than lower one; 8 – 12 per bundle, 53 – 70 µm long in anterior segments, 4 – 7 per bundle and 46 – 60 µm long in posterior ones. Penial chaetae (Fig. 13 F) in VII when mature; 1 – 3 per bundle (usually 2), 130 – 158 µm long, much larger than other, somatic crotchets. Distal end hollow and spoon-shaped. Clitellum (Fig. 14 A) in 1 / 2 VI – VIII, conspicuous, except around male pores. Paired testes at V and VI, with former pair smaller than the latter one. Paired ovaries in VII. Male funnels large, about 90 µm in diameter. Vasa deferentia (Fig. 14 A) about 140 µm long, 20 µm wide, not winding, somewhat thinner near atria; connected with atria apically. Atria globular or ovoid in shape, 90 µm long and 70 µm wide, with thick and glandular inner epithelium (Fig. 14 D). Prostate glands solid, slightly smaller than atria, connected through short stalk at lateral sides of atria. Penes conical and as large as atrium when protruding, consisting of non-glandular, loose tissues and thin inner and outer epithelia, opening into large ventromedian male bursa at middle of VII (Fig. 14 C, E). Large penial chaetophores (Fig. 14 A, F), 80 µm long, 70 µm wide, located posterior to penes in VII, consisting of a layer of tall glandular cells surrounding penial chaetae and thin muscular coverings; opening into posterior side of male bursa. Accessory glands formed by several clusters of glandular cap cells attached to dorsal side of the penial chaetophore (Fig. 14 A). Female funnel small and thin. Sperm sac restricted to VII, ovisac in VII and VIII. Spermatheca in VI (Fig. 14 A); ampulla large and globular or ovoid, and duct well marked off from ampulla, opening at chaetal line in VI ventrolaterally (Fig. 14 B). Sperm diffuse in spermathecal ampulla.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFDBE15AFF35FB0196A80F51.taxon	discussion	Remarks. Oar-shaped chaetae in dorsal bundles usually begin to appear in VII or VIII, and they completely replace bifid crotchets from VIII – XI on. Therefore, some ' transitional' chaetal bundles in VII – X have both bifid and oar-shaped chaetae, and occasionally their intermediates (Figs. 13 G – I), in addition to hair chaetae. Replacement of bifid chaetae by oar-shaped chaetae proceeds from medial to lateral in each chaetal bundle. Paired testes were observed in V and VI in all mature specimens examined. Because segment V had no efferent duct, the testes of this segment are thought to be functionless. Large penes and glandular cap cells on penial chaetophores found in the present specimens agree well with earlier descriptions of this species (Kowalewski 1914; Ohtaka & Usman, 1997). Several Aulodrilus species with oar-shaped chaetae in dorsal bundles have been described. Among them, A. remex Stephenson, 1921, A. kashi Mehra, 1922, A. prothecatus Chen, 1940 and A. tchadensis Lauzanne, 1968 have been regarded as junior synonyms of A. pigueti by several authors (Chekanovskaya 1962; Brinkhurst 1963, 1971; Brinkhurst et al. 1990; Finogenova & Arkhipova 1994; Ohtaka & Usman 1997). They share rounded oar-shaped chaetae in dorsal bundles, ovoid or bean-shaped atria, penes set in a median male bursa, and spoon-shaped penial chaetae. Cap cells on penial chaetophores are also found in the descriptions of A. remex by Aiyer (1929) and A. prothecatus by Chen (1940). A sightly swollen edge and concavity in the oar-shaped portion found in the Japanese specimens of A. pigueti were also confirmed in SEM micrographs of Russian specimens by Finogenova & Arkhipova (1994) and those of Indonesian specimens by Ohtaka & Usman (1997). Chen (1940) and Aiyer (1929) described no true penes, but instead described atrial ducts winding in large penial sacs for A. prothecatus and A. remex, respectively. Hrabě (1981) also described the atrium as ending in a very small penis, which extends into a long outlet duct in A. pigueti. These atrial ducts should be everted and protruded, forming the large pseudopenes found in the present study. Aulodrilus acutus Ohtaka & Usman, 1997 has tapering oar-shaped chaetae in dorsal bundles. This species resembles A. pigueti in having a median male bursa and globular atrium, but it differs from A. pigueti in lacking penial chaetae.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFDBE15AFF35FB0196A80F51.taxon	distribution	Distribution. A. pigueti is cosmopolitan (Brinkhurst 1971). In Japan, this species has been widespread in mesoeutrophic lakes as well as paddy fields (Ohtaka 2014; 2018 b). Aulodrilus pigueti and its relatives are common in Southeast Asia and the south Asian region (Stephenson 1921; Mehra 1922; Ohtaka & Usman 1997; Ohtaka 2018 a). Although no molecular approach has been used in the taxonomy and phylogeny of the nominal A. pigueti and its related taxa, it is probable that there are multiple lineages within the species.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFDEE15BFF35FBF495B80A99.taxon	description	(Figure 15)	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFDEE15BFF35FBF495B80A99.taxon	materials_examined	Material examined. USNM 102745 – 102746, two whole-mounted mature specimens. Saladillo River, Santa Fé Province, Argentina, coll. E. de Drago and R. Regner in 1984. R. O. Brinkhurst identified and registered. They were used under the name of Aulodrilus pigueti in Brinkhurst & Marchese (1987). Brief description. Dorsal hairs from VI, 2 – 6 per bundle. Dorsal crotchets in anterior segments 7 – 15 per bundle, with upper tooth shorter and thinner than lower one. Dorsal bifid crotchets replaced by 5 – 9 oar-shaped chaetae from IX to X. Distal parts of oar-shaped chaetae oval to rhombic in shape with midribs (Fig. 15 A, B). Ventral chaetae all bifid crotchets with upper tooth shorter and thinner than lower one, 8 – 14 per bundle in anterior segments. No lateral wings on chaetae. Male ducts in VII with short vasa deferentia and tubular atria, separately opening into male bursae in front of ventral chaetal bundles in VII (Fig. 15 C). Ventral chaetae in atrial segment not modified, 6 – 8 per bundle. Single solid prostates as large and atria. Spermathecae absent in one specimen, USNM- 102746, while present in VI in another USNM- 102745. In the latter specimen, spermathecae ampullae large and spherical with loose sperms.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFDEE15BFF35FBF495B80A99.taxon	discussion	Remarks. Aulodrilus cernosvitovi had once been regareded as a junior synonym of A. pigueti by Brinkhurst (1971); subsequently it has been regarded as a distinct species by Brinkhurst & Marchese (1989) and Ohtaka & Usman (1997). The present examination of non-type material of A. cernosvitovi from Argentina confirmed midribs on the oar-shaped chaetae, which is unique within the genus, and was described in the original description (du Bois Reymond Marcus 1947) and subsequent redescription (Howmiller 1974). In the present material, the midribs on the oar-shaped chaetae were not developed in anterior segments (Fig. 15 A), although they become prominent in posterior segments, where the distal ends changed from oval to rhombic in shape (Fig. 15 B). Tubular atria, separate openings of male pores in VII, and absence of penial chaetae, described in the original description were confirmed in the present examination; all of these are different from A. pigueti. In the figures (du Bois Reymond Marcus 1947: figs 20 A, B, 21) of the original description of A. cernosvitovi, vasa deferentia are shorter than atria and they join with atria subapically. On the other hand, in the present material, vasa deferentia are as long as or longer than atria, and they join with atria almost apically. These characters could vary depending on the fixation and orientation. In addition, absence of spermathecae was described in the original description of A. cernosvitovi (du Bois Reymond Marcus 1947), while a pair of large spermathecae containing loose sperm was found in one of the two mature Argentine specimens examined in the present study. The presence or absence of spermathecae should be regareded as intraspecific variation in A. cernosvitovi.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFDEE15BFF35FBF495B80A99.taxon	distribution	Distribution. Aulodrilus cernosvitovi has been recorded from Central to South America, including northern Brazil (du Bois Reymond Marcus 1947), Nicaragua (Howmiller 1974), and northern Argentina (Brinkhurst & Marchese 1987, under the name of A. pigueti; Brinkhurst & Marchese 1989; present study). Brinkhurst & Marchese (1989) recorded Aulodrilus pigueti along with Aulodrilus cernosvitovi in South and Central America. It is uncertain whether the record of A. pigueti of Brinkhurst & Marchese (1987) from Peru should be assigned to A. cernosvitovi or not.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFDCE159FF35FA8B97D70F35.taxon	description	(Figure 16)	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFDCE159FF35FA8B97D70F35.taxon	materials_examined	Material examined. USNM 98228 (holotype), a whole-mounted mature specimen, Piscataway Creek, Maryland, U. S. A. 3 Oct. 1979, coll. M. T. Barbour. USNM 98229, 98230, 98232, 98234, 98236 (paratypes), five whole-mount- ed mature specimens, locality, date and collector the same as for the holotype. USNM 98235 (paratype), a mature specimen sagittally sectioned and mounted on two slides, locality, date and collector the same as for the holotype. Brief description of the type series. Anterior-most six segments distinctly biannulate, each with a short anteri- or and a long posterior annulus, the latter with chaetae (Fig. 16 A). Posterior end of 0.3 mm in length without chaetae and unsegmented. Dorsal and ventral chaetae alike, each with distal nodulus and bifid, with the upper tooth shorter and thinner than the lower tooth (Fig. 16 B – D). Chaetal bundles consist of 2 – 3 chaetae in preclitellar segments and single chaeta in postclitellar segments. In the paratype specimen (USNM 98232), ventral chaetae 105 µm long in II, becoming larger in posterior segments, up to 190 µm. A single ventral chaeta in X, no chaetae in XI in mature specimen (USNM 98232). No modified genital chaetae. Spermathecae and male ducts paired in X and XI, respectively. Male funnels large, 200 – 300 µm in diameter (Fig. 16 E). Vasa deferentia (Fig. 16 F) more than 2 mm long, uniformly 38 µm wide, winding and connected with atria apically. Atria (Fig. 16 G) tubular, 250 µm long, 50 – 80 µm wide with a tall (up to 50 µm) and glandular inner epithelium and muscular coverings. Prostate glands divided into several distinct lobes, connected with atria entally through a single short stalk (Fig. 16 G arrow). Ejaculatory duct not detected, atrium leading directly to a large spherical penis in a large penial sac (Fig. 16 E). Male pores located ventrally on chaetal line of XI. Spermathecal ampullae large (Fig. 16 E), spherical or ovoid in shape and 500 µm in maximum diameter, opening laterally to ventral chaeta in X without spermathecal duct (Fig. 16 H). Within spermathecal ampullae, sperm arranged in ovoid to spindle-shaped spermatozeugmata with hyaline outer layer (Fig. 16 I).	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
EC0687D9FFDCE159FF35FA8B97D70F35.taxon	discussion	Remarks. The present examination of the type series of Aulodrilus paucichaeta confirms the original description (Brinkhurst & Barbour 1985) in the following characters: few and robust, bifid chaetae with thick lower tooth, absence of modified genital chaetae and spermathecal ducts, lobed prostate glands and spherical penes in large and muscular penial sacs. On the other hand, the present examination found several differences from the original description. The original description noted the absence of ventral chaetae in IX in mature specimen, whereas a single ordinary chaeta was found in IX in one paratype specimen. The original description depicted a small and fusiform atrium and described prostate glands as attached to atria at one point, but not obviously stalked (Brinkhurst & Barbour 1985). However, the present reexamination confirmed that the atrium is tubular and the prostate gland is connected to the atrium by a short stalk (Fig. 15 G). The original description stated that spermathecae are filled with sperm in bundles in mated specimens. However, the present examination suggests that sperms cells are arranged in ovoid to spindle-shaped capsules with a hyaline outer layer, similar to spermatozeugmata in many other tubificines. The very low number of chaetae and the extremely long and winding vas deferens are unique for Aulodrilus paucichaeta among species of the genus, suggesting that A. paucichaeta is not related closely to other congeners; this was also suggested by Finogenova & Arkhipova (1994), who highlighted the absence in this species of two characters which they considered diagnostic for the genus: the forward shift of genital organs and the lateral expansions of some chaetae, both absent in A. paucichaeta.	en	Ohtaka, Akifumi (2021): Taxonomical study of Japanese Aulodrilus Bretscher (Annelida, Clitellata Tubificinae) with descriptions of two new species. Zootaxa 4952 (1): 1-32, DOI: 10.11646/zootaxa.4952.1.1
