Gyrinicola chabadamsoni, Brigitte, Planade, Odile, Bain, Jean-Paul, Lena & Pierre, Joly, 2008

Brigitte, Planade, Odile, Bain, Jean-Paul, Lena & Pierre, Joly, 2008, Gyrinicola chabadamsoni n. sp. and G. t b a (Dinnik 1933) (Nematoda, Oxyuroidea) from tadpoles of the hybridogenetic complex Rana lessonae-esculenta (Amphibia, Ranoidea), Zootaxa 1764, pp. 25-39 : 27-32

Gyrinicola chabadamsoni n. sp. Planade and Bain

Taxonomic summary

Type-host: Rana kl. esculenta, Linnaeus , Ranidae , tadpole 109 JW V17.

Type-locality: Vernange pond (45°56’42" N, 4°55’41" E) Saint André de Corcy, Ain, France.

Site: Intestine.

Type-material: Female holotype and male allotype, N° 108 JW V17, deposited in the collection of the Museum National d’Histoire Naturelle, Paris.

Prevalence: 17.9% in June, 6.7% in August 2005 (all parasites stages and hosts).

Collection date: 06/17/2005 and 08/01/2005.

Etymology: The authors of the name G. chabadamsoni are B. Planade and O. Bain. The species is named after our colleagues Prof. Alain Chabaud, for his outstanding work on nematode parasites of vertebrates, and Dr Martin Adamson for his enlightening study of G. batrachiensis , in which he first revealed the existence of haplodiploidy in oxyurids ( Adamson 1981b and c; 1984).

Description. Female ( Fig. 1 , Table 1 a). Body cuticle with distinct annulations, except at both extremities. Maximum body width at the level of the excretory pore. Head: four tiny cephalic papillae; cylindrical salient amphids; triangular mouth surrounded by 12 conspicuous membranous flaps with longitudinal crests on posterior aspect; buccal cavity short, prolonged with an oesophageal cavity; junction of buccal cavity and oesophagus Y-shaped; no teeth. Oesophagus with thick bulb. Tiny excretory pore and complex vacuolated chamber; lateral canals prominent. Tail conical, almost regularly attenuated. Transverse slit of vulva at mid-body, muscuclar short vagina, ovijector 125-250 µm long, two uteri connected in a chamber lined with large epithelial cells. One long genital tract, apex of thick ovary at level of rectum (rarely anterior), directed anteriorly, oviduct with distinct enlarged section, uterus coiled posterior to oesophagus, then directed backwards with a bend before reaching the chamber in the longer females. The second genital tract is composed of a short ovary and a large uterine pouch containing subadult males and male larvae, shorter and sexually undetermined larvae and undifferentiated embryos.

(1) RL= Rana esculenta ; LL= R. lessonae

Male ( Fig. 3 , Table 1 b). Testis directed forwards then flexed; wide ejaculatory duct, with conspicuous vacuolated walls. No spermatozoa identified in the seminal vesicle, or in the ejaculatory duct. Genital cone: distal extremity rounded in lateral view; two pairs of papillae, one precloacal, one postcloacal. Shape of the cone-tail junction and position of the caudal papillae: the posterior aspect of the cone and the tail delineate a triangle; one pair of almost joint papillae far from the acute cone-tail angle, at about mid-length of tail; phasmids not identified. Tail attenuated. Spicule thin, with bent proximal extremity and more or less lanceolate distal part and pointed extremity.

Eggs ( Fig. 1 ). Thick-shelled eggs elliptical; dotted surface; transverse section triangular; operculum subapical, elliptical; one cell in uteri, two to 4 cells near vagina.

Taxonomic discussion. Gyrinicola chabadamsoni n. sp. is distinct from the four species already described (Tables 3 a and b). Females of G. t b a ( Dinnik 1930) have a much longer tail abruptly constricted posterior to the anus; instead of the twelve internally crested cuticular flaps, the mouth has three very thin mouth flaps, sometimes divided; the slender genital tract does not have a pouch, the eggs are less elliptical ( Fig. 1 P and Q) with operculum as wide as long. In G. t b a males, the genital cone has a long post cloacal lip and the connection of the cone-tail is square, the third pair of joined cloacal papillae is more anterior, the spicule shape is simple ( Fig. 3 D, H and I).

Gyrinicola batrachiensis (Walton 1929) close to G. t b a, has a longer female, a longer tail (518 ± 80 vs. 230 ± 38), a head with a hexagonal mouth with 6 flaps instead of 12 and 4 large papillae, a slender genital tract with thin tubular uterus containing infective third stage larvae, no uterine pouch and slightly smaller thickshelled eggs (90 ± 5 / 50 ± 6vs. 103-112/ 60–66). In the male, the body is twice as long, the tail is two and a half times longer and the shape of the genital cone differs in having a long salient posterior lip. The junction of the cone-tail is square; and the third caudal pair of papillae is more anterior.

Gyrinicola chabaudi Araujo and Artigas 1982 presents great variations of measurement (body and tail length, thick-shelled eggs). The female head has four large papillae and a mouth surrounded by three cuticular flaps constricted in the middle, and there is a long slender viviparous tract with no pouch ( Souza-Junior and Martins 1996). The male has a round genital cone as in our specimens, and the third pair of caudal papillae have a similar position but the tail is more filamentous ( Souza-Junior et al. 1991).

Gyrinicola japonica Yamaguti 1938 , which is the type species of the genus, is less acurately described, and appears to be close to our specimens. It differs in having slightly smaller eggs (87–96/48–54 vs. 103–112/ 60–66) and a male with a longer (800 to 870 vs. 617 ± 103) and slenderer (50–60/ 71± 15) body. The female has a uterine pouch with males and embryos as in our specimens.

Figures

FIGURE 1. Mature females. A – I, Gyrinicola chabadamsoni n. sp. A. Habitus left lateral view (anatomical genital parts shown: beginning of the thick ovary, thick-shelled eggs, embryos and males, V 10 FIII). B. C. D. Head in lateral, median and apical view, respectively (V 10 FII). E. Mouth surrounded with flaps showing the internal crests (V 10 FII). F. Base of the buccal cavity (V 10 FII). G. Tail ventral view (V 10 FIII). H. Thick-shelled egg two cells stage (V 10 FII). I. Detail of operculum in lateral view (V 10 FII). J – Q, G. t b a. J. Habitus left lateral view (anatomical genital parts shown: beginning of the thick ovary, thick-shelled eggs, V 60 FI). K. Head apical view (V 402). L. Mouth and cuticular lips of another specimen (E 6 FII). M. Base of buccal cavity (V 402). N. Head in lateral view (V 402). P. Thick-shelled egg four cells stage (V 16 FII). Q. Detail of operculum in sub-median view (V 16 FII). Scales in Μm A, J, 200, B – F, K – N, I, Q, 20, G, O, 150, H, P, 50.

FIGURE 3. Free males. A – E, Gyrinicola chabadamsoni n. sp. A. Habitus left lateral view. B. Cephalic region. C. Tail ventral view. D. Posterior region right lateral view. A to D male V 10 MI. E. Posterior region of holotype, left lateral view (V 17 MIII). F – I, G. t b a male E 12 MI. F. Habitus right lateral view. G. Cephalic region. H. Genital cone's region right lateral view. I. Idem semi-ventral view. Scales in Μm A, F, 150, B, C, D, G, H, I, 20, E, 50.

Tables

TABLE 1. Measurements of G. chabadamsoni n. sp. A. Females

Holotype	Other	Other	Other	Other	Other	Other	Other	Other	Other	Other
Female number V17 F I	V10 FII	V10 FIII	V11 FII	V11 FIII	V12 FI	V12 FII	V23 FI	V37 FI	V47 FI	PM5 FI
Length 2.3	1.72	1.9	2.8	2.3	1.9	1.67	2.26	2.45	2.36	2.8
Maximum width 275	250	250	350	370	280	300	200	270	250	210
Nerve ring 170	ND	120	170	165	130	145	150	160	140	150
Oesophagus 340	ND	310	380	350	330	325	400	370	370	420
Excretory pore 490	ND	380	590	ND	450	480	490	420	ND	700
Vulva 1080	ND	800	1520	ND	800	880	1080	1230	1150	1050
Tail length 210	225	240	160	250	210	290	250	270	245	180
Eggs (L/w) ND	ND	100/60	90/30	80/30	ND	ND	ND	100/40	ND	ND
Host (1) RL	RL	RL	LL	LL	LL	LL	LL	LL	LL	?
B. Males.