Dorylaimoides alpinus, Li & Baniyamuddin & Ahmad & Wu, 2008

Li, Yujuan, Baniyamuddin, M., Ahmad, Wasim & Wu, Jihua, 2008, Four new and four known species of Tylencholaimoidea (Dorylaimida: Nematoda) from China, Journal of Natural History 42 (29 - 30), pp. 1991-2010 : 2004-2007

Dorylaimoides alpinus sp. nov.

( Figure 4 ; Table 4)

Description

Female. Body cylindrical, slightly curved ventrad upon fixation, tapering slightly towards anterior and posterior end. Cuticle finely striated 1.0–2.0 mm thick at mid body and 3–4 mm on tail. Outer cuticle narrow, with fine transverse striations; inner layer comparatively thicker than the outer one. Lateral chords occupying about one-quarter of mid body width. Lateral, dorsal and ventral body pores indistinct. Lip region offset by slight depression, about twice as wide as high or about one-quarter as wide as body width at neck base. Lips amalgamated; labial papillae not interfering with labial contour. Amphids funnel-shaped, their aperture occupying about two-thirds of lip region width. Odontostyle asymmetrical, typical of the genus, its dorsal arm longer than the ventral. Guiding ring at about 0.75–0.77 of lip region width from anterior end. Stoma cylindrical. Odontophore arcuate. Nerve ring encircling the anterior slender part of pharynx at 43–45% of neck length from anterior end. Pharyngeal expansion gradual. Expanded part of pharynx occupying about 29.5–31.5% of total neck length. Cardia short conoid, rounded, about one-quarter of corresponding body width long. Genital system amphidelphic; both the sexual branches almost equally developed. Ovaries reflexed, measuring 54–61 mm (anterior) and 62–88 mm (posterior) with oocytes arranged in a single row except near tip. Oviduct joining the ovary subterminally, measuring 67–68 mm (anterior) and 66–82 mm (posterior). Uterus measuring 81–85 mm (anterior) and 66–70 mm (posterior). Vulva transverse. Vagina extending inward about two-thirds to one-half of the corresponding body width. Pars proximalis vaginae 11– 12mm with slightly convex walls encircled by circular muscles; pars refringens vaginae absent; pars distalis vaginae 5–6 mm. Prerectum 5.3–5.8 anal body widths long. Rectum 1.4–1.6 anal body widths long. Tail short conoid, gradually tapering to a blunt terminus, ventral wall almost straight, dorsal wall convex, 1.61–1.63 anal body widths long. Two caudal pores on each side.

Type habitat and locality

Soil around the roots of trees in a mixed evergreen broad-leaved forest, Ailao Mountains and Yulong Mountains, Yunnan Province, China.

Type specimens

Holotype female on slide D. alpinus sp. nov. /1; paratype female on slides D. alpinus sp. nov. /2; deposited with the nematode collection of the Department of Zoology, Aligarh Muslim University, India.

Diagnosis and relationships

Dorylaimodes alpinus sp. nov. is characterized by having 1.4–1.5 mm long, cylindrical body; lip region offset by slight depression; 12–13 mm long odontostyle; odontophore arcuate; pharyngeal expansion gradual; amphidelphic genital system and short conoid tail.

In the presence of slightly offset lip region, ampidelphic genital system, and a short conoid tail, new species resembles D. teres Thorne and Swanger, 1936 ; D. websteri Sauer, 1967 ; D. buccinator Sauer, 1967 ; D. enodis Goseco, Ferris and Ferris, 1974 and D. ornatus Peralta and Peña-Santiago, 1995 but differs from the former in having a slender body (vs a525–36), longer odontostyle (vs 6.0– 9.5 mm), longer neck (vs 180–209 mm), longer expanded part of pharynx (vs 51–63 mm), comparatively longer and differently shaped tail (vs 23–30 mm long, rounded conoid).

From D. websteri , the new species differs by having lip region offset by depression (vs lip region rather flat, offset by constriction); smaller amphid (vs amphid large, covering almost entire lateral area at that level); robust odontostyle (vs odontostyle slender, almost straight); pharyngeal expansion gradual (vs expanded part of pharynx offset by constriction); more anterior vulva position (vs V550–57), and shorter prerectum (vs 150–190 mm).

The new species differs from D. buccinator by having a longer, more slender body (vs L51.03– 1.32 mm, a537–40); lip region offset by depression (vs offset by constriction); longer odontostyle (vs 7 mm); pharyngeal expansion gradual (vs expanded part of pharynx offset by constriction); more anterior vulva position (vs V547–50), and shorter prerectum (vs 140 mm).

It differs from D. enodis by having a longer and more slender body (vs L 51.1 mm, a534.4), lip region slightly offset by depression (vs lip region amalgamated, smooth), funnel-shaped amphid (vs cup-shaped amphid), longer pharynx (vs 156.8 mm), longer pharyngeal bulb (vs 47 mm), comparatively lower c and c9 value (vs c534.4, c951.8), and more anterior vulva position (vs V544.5).

The new species is also closely related to D. ornatus Peralta and Peña-Santiago, 1995 but distinctly differs in the shape of the tail and the absence of the peculiar irregular contour on the ventral side of tail that is so characteristic of D. ornatus .

Figures

Figure 4. Dorylaimoides alpinus sp. nov. (A) Entire female; (B) anterior region; (C) anterior end showing amphid; (D) pharyngeal region; (E) expanded part of pharynx; (F) female genital branch (anterior); (G) female posterior end.