Dorylaimellus (Clavidorylaimellus) paraclavatus Siddiqi, 1968

Ahmad, Wasim & Naz, Tabbasam, 2012, Four new and six known species of the genus Dorylaimellus Cobb, 1913 (Nematoda: Belondiridae) from India, Journal of Natural History 46 (45 - 46), pp. 2787-2828 : 2815-2818

Dorylaimellus (Clavidorylaimellus) paraclavatus Siddiqi, 1968

( Figures 14 and 15 ; Table 8)

Description

Female. Body curved ventrad upon fixation, tapering towards both extremities. Cuticle with transverse striations, more pronounced towards extremities, 2–3 µm thick at mid body and 2.0 µm on tail. Lateral chords without distinct glandular bodies, about one-quarter to one-third as wide as body width at mid body. Lateral, dorsal and ventral body pores indistinct. Lip region offset, about twice as wide as high or about one-quarter as wide as body width at neck base. Cheilostome a truncate cone with refractive walls and well-developed cuticularized plates around oral aperture. Amphids stirrup-shaped, their aperture about 0.8 times as wide as lip region width. Odontostyle fusiform, about as long as lip region width, its aperture about one-third of its length. Guiding ring at 0.8 times lip region width from anterior end. Odontophore rod-like with basal flanges, 1.8–2.5 times the odontostyle length. Nerve ring at 29–32% of neck length from anterior end. Pharyngeal expansion abrupt; expanded part occupying about 51–58% of total neck length, enclosed in a thick sheath of dextrally spiral muscles. Cardia elongate-conoid, slightly more than one-half of the corresponding body width long. Genital system amphidelphic; both the sexual branches almost equally developed. Ovaries reflexed, measuring 45–97 µm (anterior) and 37–65 µm (posterior) with oocytes arranged in a single row except near tip. Oviduct joining ovary subterminally, measuring 20–50 µm (anterior) and 20–32 µm (posterior) long. Well-developed sphincter present at oviduct–uterus junction. Uterus a simple tube, measuring 25–27 µm (anterior) and 20–25 µm (posterior). Vulva longitudinal. Vagina extending inward, about one-third of corresponding body width deep; pars proximalis vaginae 7–9 µm long with convex walls; pars refringens vaginae absent; pars distalis vaginae 1.5–2.5 µm with rounded walls. Prerectum about 3.1–3.8 times anal body width long. Rectum about 1.0–1.3 times anal body width long. Tail dorsally convex conoid at first, then elongate with clavate tip, 3.3–3.8 times anal body width long. Caudal pores two on each side.

Male. Not found.

Habitat and locality

From soil around the roots of shrubs near Arunachal Gate checkpoint, Assam- Arunachal Border, Changlang, Arunachal Pradesh; 27 ◦ 07 ′ 0 ′′ N, 95 ◦ 43 ′ 0 ′′ E; altitude 213 m above sea level.

Remarks

Dorylaimellus paraclavatus was described by Siddiqi (1968) from Sibsagar Assam, India. The present population from Manipur conforms well with the original description except for having slightly smaller b value (b = 3.6–4.1 vs 4.3–4.5). In tail shape, D. paraclavatus comes close to D. (C.) clavatus Thorne 1964 ; D. (C.) nygellurus Loof, 1964 ; D. (C.) spicatus Loof, 1964 and D. (D.) virginianus Cobb, 1913 . From D. (C.) clavatus this species differs in having longer odontostyle (6–7 vs 4–5 µm), smaller pharynx (b = 3.6–4.1 vs 3), slightly anterior located vulva (48–51% vs 53%) and shorter tail (c = 13–16.8 vs 12) and from D. (C.) spicatus it differs in having smaller pharynx (b = 3.6–4.1 vs 2.7–3.2) and tail tip not clavate. From D. (C.) nygellurus it differs in having longer body (L = 0.8–1.03 vs 0.64–0.67 mm), longer odontophore (14–15 vs 8.5 µm) and shorter tail (c = 13–16.8 vs 7–9). From D. (D.) virginianus it differs in having smaller body length (L = 0.8–1.03 vs 1.4 mm) and longer tail (c = 13–16.8 vs 25).

Figures

Figure 14. Dorylaimellus (Clavidorylaimellus) paraclavatus Siddiqi, 1968. (A) Entire female, (B) anterior region, (C) anterior end showing amphid, (D) pharyngeal region, (E) female genital system, (F) female posterior region.

Figure 15. Dorylaimellus (Clavidorylaimellus) paraclavatus Siddiqi, 1968. (A) Anterior region, (B) female genital system, (C) female posterior region. Scale bars: A–C = 20 µm.