Trileptium ribeirensis, Vilas-Boas & da Silva & de Souza Alves & de Castro & Pinheiro-Junior, 2016

Vilas-Boas, Ana C., da Silva, Maria C., de Souza Alves, Orane F., de Castro, Francisco J. V. & Pinheiro-Junior, Eraldo P., 2016, A new species of Trileptium (Nematoda: Thoracostomopsidae) from Bahia, Brazil, Zoologia (e 20150043) 33 (1), pp. 1-10 : 3-4

Trileptium ribeirensis sp. nov.

Figs. 2-17 , Table 1

urn:lsid:zoobank.org:act:1047B3EC-5851-43A7-96D5-37D49CAF6FB0

Diagnosis. Slightly striated cuticle, visible in the anterior region and through the tail. Three lips. Cephalic arrangement in three rings, outer-labial setae greater than cephalic setae. Males with two pairs of sub-cephalic setae. Narrow buccal cavity with three jaws and three isometric teeth, all on the same level and across the transverse mandibular bar. Males with two opposite testis left to the intestine. Simple shaped spicules. Laminar gubernaculum with a dorsal-caudal apophysis. Tubular pre-cloacal supplement. Conical tail tapering at the terminal portion.

Type material. Holotype (male): Brazil, Bahia: Salvador ( Ribeira Beach , 12°55’S, 38°30’W), 10-20 cm depth, collected with a corer, middle region, coarse sand, 45µm sieve), 11.II.2009, Alves, O.F.S. et al. leg., Museu de História Natural da Bahia, Brazil ( UFBA NEM01063 ) . Allotype (female): Brazil, Bahia: Salvador ( Ribeira Beach , 12°55’S, 38°30’W, 0-10 cm depth, collected with a corer, middle region, medium sand, 500 µm sieve), 09.II.2009, Alves, O.F.S. et al. leg., Museu de História Natural da Bahia, Brazil ( UFBA NEM00371 ) . Paratypes: Brazil, Bahia: Salvador ( Ribeira Beach , 12°55’S, 38°30’W, 0-30 cm depth, collected with a corer, middle region, medium sand, 45 and 500 µm sieves), 9 males and 4 females, 11.II.2009; Alves, O.F.S. et al. leg., Museu de História Natural da Bahia, Brazil ( UFBA NEM00509 , UFBA NEM00963 , UFBA NEM01036 , UFBA NEM01055 , UFBA NEM01166 , UFBA NEM01171 , UFBA NEM01217 , UFBA NEM01224 , UFBA NEM01351 , UFBA NEM01357 , UFBA NEM01358 , UFBA NEM01366 , UFBA NEM01388 ) .

Description. Holotype: Slender and elongated body, particularly in the extremities (Length: 3713 µm). Slightly striated cuticle, visible in the anterior region, even after the nerve ring, and little less in the cloaca region extending through the tail. Narrow head with a sclerotized cephalic capsule. Presence of three lips. Cephalic arrangement in 6 + 6 + 4: six inner-labial thick and short setae (6 µm) and six outer-labial setae (50 µm) greater than cephalic setae (30 µm). Two pairs of sub-cephalic setae were also observed (31 µm). Somatic setae (13 µm) up to the nerve ring and absent in the rest of the body. Presence of orthometanemes, with one complete filament with 24 µm. Narrow buccal cavity with three jaws (20 µm) and three isometric teeth (13 µm), all on the same level and across the transverse mandibular bar. Pocket-shaped amphidial fovea, near the base of the cephalic capsule, which occupies 17% of the corresponding body diameter. Circular cephalic ring positioned between the inner labial setae circle and the outer labial setae circle (1 µm from the anterior end). Cylindrical pharynx with crenated contour and without a terminal bulb (742 µm). Triangular cardia inserted in the intestine. No excretory-secretory system was observed. Two opposite testis (anterior 138 µm, and posterior 123 µm) left to the intestine. Simple shaped spicules lacking capitulum and velum, ventrally curved (56 µm). Laminar gubernaculum (13 µm) with a dorsal-caudal apophysis (6 µm). Presence of a sclerotized and tubular pre-cloacal supplement (8 µm) 38 µm from the cloaca. Conical tail (189 µm) tapering at the terminal portion, with irregularly distributed setae (5 to 8 µm). No caudal glands were observed. Presence of spinneret (4 µm).

Allotype: Similar to the description of the male, except for the sub cephalic setae, which are present only in males. The sub cephalic setae is a sexual dimorphism in this species. Females had a didelphic reproductive system with opposite reflected ovaries (anterior 1984 µm, and posterior 1990 µm) left to the intestine. The vulva is located 2700 µm from the anterior end, equivalent to 63% of the body length. Only non-gravid females were observed.

Etymology. The species’ name honors the site where the animals were collected. This is the first description of a new species of Nematode for Ribeira Beach, Salvador, Bahia, Brazil.

Figures

Figures 2-7. Holotype of Trileptium ribeirensis sp. nov.: anterior region showing setae (2), cephalic ring and amphid (3), orthometaneme (4) and teeth and jaws (5); posterior region with emphasis on the supplement (6) and the spicules and gubernaculum (7). Scale bars = 20 µm.

Figures 8-12. Holotype of Trileptium ribeirensis sp. nov.: (8) anterior region showing cephalic ring, amphid and cuticle; (9) total body; (10) body region with pharynx, nerve ring, somatic seta and cardia; (11) anterior region emphasizing setae and teeth; (12) spicules and gubernaculum. Scale bars: 8, 10, 11 = 50 µm, 9 = 200 µm, 12 = 20 µm.

Figures 13-17. Allotype of Trileptium ribeirensis sp. nov.: (13) total body; (14) anterior region with pharynx, nerve ring, somatic seta and cardia; (15) body region showing the vulva and ovaries; (16-17) anterior region emphasizing the cephalic ring and amphid: (16), teeth and jaws (17). Scale bars: 13 = 200 µm, 14, 15 = 100 µm, 16, 17 = 50 µm.

Tables

Table 1. Males and females measurements (µm) of Trileptium ribei- rensis sp. nov. (cbd) corresponding body diameter; (V%) position of vulva as a percentage of body length from the anterior end; (a) body length divided by maximum body diameter; (b) body length divided by pharyngeal length; (c) body length divided by tail length; (c’) tail length divided by body width at the anus or cloacal opening.

	Holotype male	Paratypes (males = 9)	Alotype female	Paratypes (females = 4)
Body length	3713	2359-4415	4320	3489-4211
Head length	20	20-25	23	21-24
Head width at cephalic ring	17	14-18	15	15-20
Head to cephalic ring distance	1	2-3	2	2-3
Head width at lips	14	12-16	15	14-17
Maximum width at lips	18	16-18	19	19-21
Amphid width	4	4	4	3-5
Amphid cbd	24	20-28	25	23-30
Buccal cavity length	30	26-32	34	29-34
Buccal cavity cbd	19	18-21	21	19-22
Onchium length	13	10-12	12	10-15
Jaw length	20	9-13	16	13-16
Cephalic capsule length	22	19-24	23	21-25
Width at base of cephalic capsule	23	22-25	26	24-27
Inner labial setae length	6	4-7	6	4-6
Outer labial setae length	50	44-51	41	40-45
Cephalic setae length	30	16-28	17	11-15
Longest subcephalic setae length	31	23-31	–	–
Somatic setae length	13	10-14	13	10-13
Head to nerve ring distance	172	154-210	189	160-182
Nerve ring cbd	44	42-53	49	46-54
Pharynx length	742	713-895	782	692-766
Anterior testis length	138	50-143	–	–
Posterior testis length	123	55-118	–	–
Anterior ovary length	–	–	1984	771-1360
Posterior ovary length	–	–	1990	841-1878
Head to cloaca/anus distance	3524	2161-4192	4138	3307-4005
Head to vulva distance	–	–	2700	2296-2710
Tail length	189	177-223	181	178-206
Spicules, arc length	56	55-62	–	–
Spicules, chord length	48	47-56	–	–
Sppineret length	4	3-5	4	4-5
Gubernaculum length	13	9-16	–	–
Apophysis length	6	4-8	–	–
Supplement length	8	6-9	–	–
Supplement to cloaca distance	38	37-48	–	–
Maximum body width	46	44-56	62	53-65
Width at cloaca/anus	38	38-48	46	44-52
Orthometanemes length	24	28-39	36	24-45
V%	–	–	62.5	62.1-66.8
a	81.0	44.5-86.5	69.6	56.8-69.8
b	5.0	2.7-4.9	5.5	4.6-5.5
c	19.6	11.9-21.7	23.8	19.1-20.8
c’	4.9	3.7-5.2	4.0	3.0-4.0