Proleptonchus sinensis, 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 : 2001-2004

Proleptonchus sinensis sp. nov.

( Figure 3 ; Table 3)

Description

Female. Body curved ventrad upon fixation, tapering towards both extremities. Cuticle 2.0 mm thick at mid body and 3–4 mm on tail, inner layer coarsely striated, loose. Radial refractive elements abundant along entire body length. Lateral chords about one-quarter to one-third of mid body width. Lateral, dorsal and ventral body pores indistinct. Lip region low, offset by depression, about three times as wide as high or about one-third as wide as body width at neck base. Lips rounded, amalgamated. Amphids with cup-shaped fovea; their aperture occupying about 0.5– 0.7 lip region width. Stoma flask-shaped. Odontostyle typical of the genus, slender, attenuated, 0.8 lip-region-width long. Guiding ring at 0.70–0.81 lip-region-width from anterior end. Odontophore arcuate with simple base, 1.5 odontostyle length. Pharynx with slender, weakly muscular anterior part separated from expanded part by deep constriction. Pharyngeal bulb occupying about 19–20% of total neck length. Nerve ring encircling anterior slender part of pharynx at 44–49% of neck length from anterior end. Cardia rounded, conoid, about one-third of corresponding body width long. Genital system pseudo-monoprodelphic. Anterior genital branch normal; ovary reflexed, measuring 103–115 mm, with oocytes arranged in a single row except near the tip. Oviduct joining ovary subterminally, measuring 198–243 mm, with welldeveloped pars dilatata. Sphincter at oviduct–uterus junction distinct. Uterus 75– 117 mm long; posterior genital branch represented by a 2.3–2.5 mid body widths long sac with rudiments of oviduct. Vulva transverse. Vagina extending inwards about one-half of corresponding body width. Pars proximalis vaginae 11–12 mm with convex walls encircled by circular muscles; pars refringens vaginae absent, pars distalis vaginae 6–7 mm with curved walls. Prerectum 2.9–3.6 anal body widths long. Rectum 1.14–1.35 anal body widths long. Tail short, conoid, 0.58–0.67 anal body widths long. Cuticle thick at tail terminus. Caudal pores two on each side.

Male. Similar to female in general morphology except the posterior region is more curved ventrally because of the presence of copulatory muscles. Supplements an adanal pair and four ventromedians. Spicules slender, slightly arcuate about 1.34 anal body widths long. Lateral guiding pieces about one-quarter of spicule length. Prerectum 3.6 anal body widths long. Rectum about as long as anal body width. Tail short, conoid, 0.65 anal body widths long, with finely rounded terminus. Caudal pores two on each side.

Type habitat and locality

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

Type specimens

Holotype female on slide P. sinensis sp. nov. /1; a paratype female and a male on slides P. sinensis sp. nov. /2–3, deposited with the nematode collection of the Department of Zoology, Aligarh Muslim University, India. A paratype female on slides P. sinensis sp. nov. /4 deposited with the nematode collection of Fudan University, China.

Diagnosis and relationships

Proleptonchus sinensis sp. nov. is characterized by having 1.5–1.7 mm long body; lip region low, offset by depression; amphids wide stirrup shaped; 8–9 mm long odontostyle; pseuo-monoprodelphic female genital system, posterior genital branch with well-developed uterus and small rudimentary terminal oviduct and short conoid tail with thick cuticle at terminus.

The new species closely resembles P. fagi Jimenez-Guirado and Arcos, 1994 ; P. johnsoni Goseco, Ferris and Ferris, 1974 ; P. aestivus Lordello, 1955 ; P. lacihoveyensis Goseco, Ferris and Ferris, 1974 and P. saccatus Clark, 1962 .

From P. fagi , the new species differs by having the lip region offset by depression (vs offset by constriction); in the absence of disc-like perioral area (vs disc-like perioral area present); cardia shape (conoid vs rounded); posterior genital branch rudimentary with a sac-like uterine part and barely demarcated rudiments of oviduct (vs oviduct, though rudimentary, with a recognizable pars dilatata, and reduced sphincter between oviduct and uterus), in the shape of female tail (vs hemispheroid to clavate), smaller spicules (vs 41–50 mm), and regularly spaced ventromedian supplements (vs irregularly spaced).

From P. johnsoni , the new species differs by having indistinct labial papillae (vs distinct); longer and differently shaped pharyngeal bulb (vs 32 mm; more cylindrical); shorter post-uterine sac (vs G 259.5); shorter prerectum (vs 134–224 mm); comparatively higher c value (vs c569–75) and by the presence of male (vs absence).

From P. aestivus , the new species differs by having longer and slender body (vs L51.2– 1.5 mm, a532–35), comparatively longer odontostyle and odontophore (vs odontostyle 7.0– 8.5 mm, odontophore 10–12 mm), amphid simple (vs duplex), longer post-uterine sac (vs 46 mm), in the nature of posterior genital branch (vs posterior genital branch a simple sac without sphincter and rudiments of oviduct); and in the presence of male (vs absence).

From P. lacihoveyensis , the new species differs in having a longer body (vs L51.22– 1.55 mm); simple amphid (vs duplex); longer expanded part of pharynx (vs 31–37 mm); prerectum–intestine junction simple (vs prerectum–intestine junction guarded by three small cells); and longer spicules (vs 27 mm).

From P. saccatus , the new species differs in having simple amphid (vs duplex), amphid aperture simple (vs aperture sinuous, bi-crescentic); comparatively shorter and simple odontophore (vs odontophore distinctly sclerotized 15 mm long), shorter post-uterine sac (vs G 2512), shorter prerectum (vs 160 mm); and shorter spicules (vs 48–49 mm).

Figures

Figure 3. Proleptonchus sinensis sp. nov. (A) Entire female; (B) entire male; (C) anterior region; (D) anterior end showing amphid; (E) pharyngeal region; (F) expanded part of pharynx; (G) female genital branch; (H) female posterior end; (I) male posterior region.