Dorylaimellus (Dorylaimellus) shamimi, Ahmad & Naz, 2012

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 : 2788-2792

Dorylaimellus (Dorylaimellus) shamimi sp. nov.

( Figures 1 and 2 ; Table 1)

Description

Female. Body curved ventrad upon fixation, tapering towards both extremities. Cuticle with distinct transverse striations, more pronounced towards extremities, 2–3 µm thick at mid body and 4.0 µm on tail. Lateral chords about one-quarter to one-third as wide as body width at mid body, glandular organs indistinct. Lateral, dorsal and ventral body pores indistinct. Lip region offset, about twice as wide as high or about one-third as wide as body width at neck base; lips more or less rounded, amalgamated. Amphids stirrup-shaped, their aperture about 0.8 times as wide as lip region width. Cheilostome a truncate cone with refractive walls and cuticularized plates close to oral opening. Odontostyle as long as lip region width, its aperture about one-third of its length. Odontophore about twice the odontostyle length with well-developed basal flanges. Nerve ring at 38–41% of neck length from anterior end. Pharyngeal expansion abrupt; expanded part occupying about 35–43% of total neck length, enclosed in a thick sheath of dextrally spiral muscles. Cardia conoid, about one-third of the corresponding body width long. Genital system amphidelphic; both the sexual branches almost equally developed. Ovaries reflexed, measuring 45–60 µm (anterior) and 45–60 µm (posterior) with oocytes arranged in a single row except near tip. Oviduct joining ovary subterminally, measuring 35–60 µm (anterior) and 40–60 µm (posterior) long. Sphincter indistinct at oviduct–uterus junction. Uterus measuring 50 µm (anterior) and 30 µm (posterior). Vulva longitudinal. Vagina extending inward, about two-thirds of the corresponding body width; pars proximalis vaginae 12–13 µm long with almost straight walls; pars refringens vaginae absent; pars distalis vaginae 1.5–2.0 µm with rounded walls. Prerectum 3.5–6.0 times anal body width long. Rectum about as long as anal body width. Tail conoid, ventrally arcuate, 2.6–3.3 times anal body width long. Caudal pores two on each side.

Male. Not found.

Type habitat and locality

From soil around the roots of forest trees (unidentified) near Maulai village, Shillong , Meghalaya. 25 ◦ 34 ′ 0 ′′ N, 91 ◦ 53 ′ 0 ′′ E, altitude 1496 m above sea level .

Type specimens

Holotype female on slide Dorylaimellus (D.) shamimi sp. nov. / 1; paratype females on slides Dorylaimellus (D.) shamimi sp. nov. / 2–8; deposited with the nematode collection of the Department of Zoology, Aligarh Muslim University, India. Two paratype females deposited with the nematode collection of the Universidad de Jaén, Spain.

Etymology

The new species is named after Prof. M. Shamim Jairajpuri in recognition of his contributions to the field of nematode taxonomy.

Diagnosis and relationships

Dorylaimellus (Dorylaimellus) shamimi sp. nov. is characterized by having body 1.1–1.2 mm long; offset lip region with amalgamated lips; odontostyle 7–8 µm and odontophore 10–14 µm long; expanded part of pharynx about 35–43% of total neck length; longitudinal vulva at 47–50%; amphidelphic female genital system and 2.6–3.3 anal body widths long, conoid ventrally arcuate tail.

In the absence of peri-oral disc, presence of longitudinal vulva, amphidelphic female genital system and conoid ventrally arcuate tail, the new species belongs to the subgenus Dorylaimellus Jairajpuri and Ahmad, 1980 and comes close to Dorylaimellus sewaki Bohra and Baqri, 2005 and Dorylaimellus himalayensis Ali, Jairajpuri and Coomans, 1974 . From former, it differs, in having longer body size (L = 1.1–1.2 vs 0.8–0.9 mm), relatively shorter pharynx (b = 6.1–7.0 vs 5.0–5.3), anterior vulva position (V = 47–50% vs 59–61%), longer tail (c = 19.2–22.7 vs 24–26, c′ = 2.6–3.3 vs 2.0–2.1) and absence of male (vs presence).

From D. himalayensis , the new species differs in having relatively shorter body length (L = 1.1–1.2 vs 1.2–1.5 mm), shorter odontostyle and odontophore (odontostyle 6–8 vs 10–12 µm, odontophore 10–12 µm vs 17–18 µm), shorter pharynx (b = 6.1–7.0 vs 4.2–4.9), anterior part of pharynx lacking spindle-shaped valved area (vs spindle-shaped valved area present) and expanded part of pharynx less than half of total neck length (vs expanded part more than half of total neck length).

The new species also closely resembles Dorylaimellus murtazai Baqri, 1991 in body size and the size of expanded part of pharynx but differs in the shape of lip region being more rounded (vs more conoid), comparatively longer pharynx (b = 6.1–7.0 vs 7.6–7.8), longer prerectum (100–130 vs 33–40 µm) and shorter, differently shaped tail (c= 19.2–22.7 vs 17.2–18.3, c′ = 2.6–3.3 vs 3.1–3.6, tail elongate conoid, slightly curved ventrally).

Figures

Figure 2. Dorylaimellus (Dorylaimellus) shamimi sp. nov. (A) Anterior region, (B) anterior end showing amphid, (C,D) expanded part of pharynx, (E,F) vulval region, (G) female posterior region. Scale bars: A, B = 10 µm; C–G = 20 µm.