Thornia propinqua ( Paesler, 1941 ) Andrássy, 1957

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 : 2975-2979

Thornia propinqua ( Paesler, 1941) Andrássy, 1957

( Figures 5 and 6; Table 3)

Tylencholaimus propinquus Paesler, 1941 .

Description

Female. Body straight to slightly curved ventrad upon fixation, tapering slightly towards both extremities. Cuticle finely striated, 1.5–2.0 µm thick at mid-body and 2–3 µm on tail. Lateral chords about one-quarter corresponding body width wide at mid-body. Lateral, dorsal and ventral body pores absent. Lip region continuous, rounded, two-fifths to one-third of body width at neck base. Lips amalgamated; outer and inner labial papillae close together, not interfering with the labial contour. Amphids elongate, wine-glass shaped, occupying about two-fifths of the corresponding body width. Odontostyle straight, sharply pointed at its tip, and somewhat swollen in its posterior half, about one lip region width long, its aperture about one-quarter of its length. Guiding ring single, fixed ring at 0.41–0.53 lip region width from anterior length of body. Pharyngeal gland nuclei located as follows: D, 55–58; AS 1, 20–24; AS 2, 43–46; PS1, 73–75; PS2, 78–81. Genital system amphidelphic; both the sexual branches almost equally developed. Ovaries reflexed, measuring 47–83 µm (anterior) and 43–102 µm (posterior) with oocytes arranged in a single row except near tip. Oviduct joining ovary subterminally, measuring 55–100 µm (anterior) and 65–103 µm (posterior). A weak sphincter present at the oviduct–uterus junction. Uterus a simple tube measuring 62–92 µm (anterior) and 50–111 µm (posterior). Vagina about onethird of the corresponding body width deep. Pars proximalis vaginae 7–8 µm long with convex walls; pars refringens vaginae absent; pars distalis vaginae 4–5 µm with curved wall. Vulva transverse oval, apparently a pore. Pre-rectum 2.0–2.4 times anal body width long. Rectum one anal body width long. Tail short, straight, cylindrical, slightly subclavate with rounded terminus, 1.6–2.0 anal body widths long; one terminal, one subdorsal and one subventral caudal pore.

Male. Males similar to female in general morphology. Supplements consisting of only a very weakly developed ad-cloacal pair, ventromedians absent. Spicules simple, slen- der, non-dorylaimoid without median piece, 0.86–0.90 times anal body width long. Gubernaculum thin, about 0.38–0.42 times the spicules length. Tail short, straight, cylindrical with rounded terminus, 1.6–1.8 times anal body widths long, with inner cytoplasmic core conical leading to terminal caudal pore; ventral pore near middle of tail and a lateral pore in posterior third of tail also present.

Habitat and locality

Soil around the roots of forest trees, grasslands, Kaziranga National Park, Assam, India.

Remarks

Paesler (1941) described this species as Tylencholaimus propinquus from Holland. Andrássy (1957) transferred it to the genus Thornia as Thornia propinqua and synonymized Thornea regiusi Meyl, 1955 with this species. Later, Andrássy (1987) redescribed this species and the male was reported for the first time from an Indian as well as a Hungarian population. This species has been reported from many European countries as well as from Russia and India. The present population from Kaziranga National Park, Assam conforms well with those described by earlier authors except for some differences in odontostyle length (versus 10–12 µm); slightly higher c value (versus c, 20–28); differently shaped vagina (versus vagina heart-shaped), vulva transverse oval, apparently a pore (versus vulva transverse); comparatively more posterior vulva position (versus 42–47) and slightly smaller spicules (versus spicules 18–20 µm). This may be because of geographical variation.

Figures

Figure 5. Thornia propinqua (Paesler, 1941) Andrássy, 1957. (A) Anterior region, (B) pharyngeal expansion, (C) posterior genital branch, (D) vulval region, (E) female posterior region, (F) male posterior region.