Prothornenema vulvatum, Baniyamuddin & Ahmad, 2011

Baniyamuddin, Md. & Ahmad, Wasim, 2011, Two new and a known species of dorylaim nematodes (Dorylaimida: Nematoda) from Kaziranga National Park, Assam, India, Journal of Natural History 45 (47 - 48), pp. 2965-2980 : 2966-2970

Prothornenema vulvatum sp. nov.

( Figures 1 and 2; Table 1)

Description

Female. Body slightly curved ventrad upon fixation, tapering slightly anterior to base of pharynx, posteriorly ending in a long filiform tail. Cuticle finely striated, 1.0–1.5 µm thick at mid-body and 2–3 µm on ventral side of tail just posterior to anus. Lateral chords about one-quarter of the body width at mid-body. Lateral, dorsal and ventral body pores indistinct. Lip region cap-like, slightly rounded, offset by constriction with moderate labial and post-labial sclerotization, about twice as wide as high and one-quarter as wide as body width at neck base. Amphids cup-shaped, their aperture slightly less than half of lip region width. Odontostyle 1.1–1.2 times lip region width long, its aperture about one-third of its length. Guiding ring single, fixed ring at about one lip region width from anterior end. Odontophore simple rod-like, about 1.3 times the odontostyle length. Nerve ring at 45–46.5% of neck length from anterior end. Pharyngeal expansion gradual; expanded portion occupying about 28–29% of neck length. Cardia short conoid to rounded, about one-third of corresponding body width long. An oval subdorsal glandular mass (pseudocoelomocytes) present at about one body width behind pharyngo-intestinal junction. Pharyngeal gland nuclei located as follows: D, 72–74; AS 1, 18–21; AS 2, 38–42; PS1, 74–76; PS2, 75–76. Genital system amphidelphic, both the sexual branches almost equally developed. Ovaries reflexed, measuring 53–83 µm (anterior) and 45–75 µm (posterior) with oocytes arranged in a single row except near tip. Oviduct joining ovary subterminally, measuring 88–100 µm (anterior) and 85–93 µm (posterior). Sphincter present at oviduct–uterus junction. Uterus apparently bipartite, measuring 71–84 µm (anterior) and 53–75 µm (posterior), with two sections of nearly same length, the distal part comparatively more strongly muscular with distinct cells. Vagina thick-walled, about two-thirds of the corresponding body width deep; pars proximalis vaginae 12.0–12.5 µm long with concave walls, encircled by circular musculature; pars refringens vaginae with triangular sclerotization, each measuring 3.0–3.5 by 5.0–5.5 µm, a well-developed median triangular piece present between two sclerotized pieces, measuring 3.0–3.5 by 3.5–4.0 µm; cw, 9–10; pars distalis vaginae 2.5–3.0 µm long with curved wall. Vulva transverse, cuticle both anterior and posterior to vulva with two or three deep infoldings. Pre-rectum 3.5–4.2 times anal body width long. Rectum 1.7 times anal body width long. Tail long filiform, 6.3–7.3 times anal body width long with three caudal pores on each side.

pieces rod-like, about one-quarter of spicule length. Pre-rectum 4.5–4.6 anal body widths long, terminating within the range of supplement. Tail short conoid, its ventral wall nearly straight whereas the dorsal wall is convex, about as long as anal body width. Caudal pores three, one ventral just posterior to cloaca, one terminal and one subdorsal in the posterior third of tail.

Type habitat and locality

Soil around the roots of forest trees from Kohora range, Kaziranga National Park, Assam. India.

Type specimens

Holotype female on slide P. vulvatum sp. nov. / 1; paratype males and females on slides P. vulvatum sp. nov. / 2–3; deposited with the nematode collection of the Department of Zoology, Aligarh Muslim University, Aligarh.

Diagnosis and relationships

Prothornenema vulvatum sp. nov. is characterized by having body 1.06–1.17 mm long; lip region cap-like, slightly offset by constriction with moderate labial and post-labial sclerotization; 10–11 µm long odontostyle; vulva a transverse slit, cuticle both anterior and posterior to vulva with two or three deep invaginations; female tail long filiform, 6.3–7.3 times anal body width long; males with 13 or 14 contiguous ventromedian supplements and pre-rectum terminating within the range of supplements.

The new species, as its name indicates, is distinctive because of the nature of its pars refringens vaginae and the cuticular infolding both anterior and posterior to vulva. It further differs from the type and only species of the genus, Prothornenema capitatum Baqri and Bohra, 2003 , in having comparatively broader lip region (8–9 versus 6–7 µm) with rounded lips (versus angular lips); longer pharynx in males (198–200 versus 180–182 µm; b = 5.3–5.4 versus 5.7–6.0); in the structure of pars refringens vaginae in females (three pieces versus two); comparatively longer spicules (38–40 versus 30 µm) and fewer ventromedian supplements (13–14 versus 15–17).

Etymology

The new species is so named because of the presence of cuticular infoldings near vulva.

Figures

Figure 1. Prothornenema vulvatum sp. nov. (A) Anterior region, (B) anterior end showing amphid, (C) pharyngeal region, (D) pharyngeal expansion, (E) posterior genital branch, (F) vulval region, (G) female posterior region, (H) female posterior end, (I) male posterior region.