Tantunema pakistanense Timm 1964, comb. nov.
Creators: name: Ahad, Sumaya
name: Ahmad, Wasim
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Nematoda
Adenophorea
Dorylaimida
Tylencholaimidae
Tantunema
Tantunema pakistanense

description: <i>Tantunema pakistanense</i> (Timm, 1964) comb. nov. (Figures 3 and 4; Table 2) <i>Description</i> <i>Female.</i> Small-sized nematodes, slightly curved upon fixation; body cylindrical tapering slightly towards both the extremities. Cuticle with two distinct layers, 1 μm thick at midbody and 2.0 <i>–</i> 2.5 μm on tail. Outer cuticle smooth; inner finely transversely striated. Lateral chords occupying about one-third of midbody diameter. Lateral, dorsal and ventral body pores indistinct. Lip region cap-like, rather low, offset by slight depression, 1.6 <i>–</i> 2.0 times as wide as high or about one-third of the body diameter at neck base. Lips angular, labial papillae slightly raised. A weakly developed post-labial sclerotization present. Amphids small, aperture a short transverse slit. Cheilostome a truncate cone. Odontostyle slender, 1.0 <i>–</i> 1.2 times the lip region diameter long, its aperture about onesixth or one-fifth of the odontostyle length. Odontophore rod-like with slight basal thickening, 1.3 times the odontostyle length. Guiding ring simple, refractive, at 0.6 <i>–</i> 0.8 times lip region diameter from anterior end. Pharynx consists of a slender and weakly muscular anterior part, expanding gradually into a cylindrical basal expansion, occupying about 33 <i>–</i> 35 % of total neck length. Pharyngeal gland nuclei and their orifices located as follows: DO = 71 <i>–</i> 73, DN = 75 <i>–</i> 76, DO <i>–</i> DN = 3.6 <i>–</i> 3.7, S 1 N 1 = 80 <i>–</i> 83, S 1 N 2 = 84 <i>–</i> 86, S 2 N = 92 <i>–</i> 93, S 2 O = 93 <i>–</i> 94. Cardia short, conoid, about one-third of the corresponding body diameter long. Nerve ring located at 44 <i>–</i> 45 % of neck length from anterior end. Genital system mono-opisthodelphic. Ovary reflexed, measuring 37 <i>–</i> 41 µm long, oocytes arranged in single row except near tip. Oviduct joining the ovary subterminally; oviduct separated from the uterus by a narrowing but no apparent sphincter seen; uterus measuring 28 <i>–</i> 35 µm and oviduct measuring 22 <i>–</i> 27 µm. Anterior genital branch completely absent. Vagina directed posteriorly; <i>pars proximalis vaginae</i> 5 <i>–</i> 6 µm long, its wall encircled by muscles; <i>pars distalis vaginae</i> short, 1.0 <i>–</i> 1.5 µm long with slightly curved walls; <i>pars refringens absent</i>. Vulva apparently a transverse slit. Prerectum 2.1 <i>–</i> 2.5 and rectum 0.5 <i>–</i> 1.0 times anal body diameter long. Tail short, rounded <i>–</i> conoid, 1.1 <i>–</i> 1.2 anal body diameter long. Caudal pores two on each side. <i>Male.</i> Not found. <i>Habitat and locality.</i> Soil samples around the roots of the bushy trees from Naqvi Park, Aligarh, Uttar Pradesh, India. <i>Remarks</i> Timm (1964) described <i>Tylencholaimus pakistanensis</i> from erstwhile East Pakistan (now Bangladesh). The nature of its lip region, the presence of small amphid with a short transverse slit-like aperture and weak post-labial sclerotization puts this species well under the generic diagnosis of <i>Tantunema</i> rather than <i>Tylencholaimus</i>. Hence, it is transferred here to <i>Tantunema</i> as <i>Tantunema pakistanense</i> (Timm, 1964) comb. nov. The present population from India conforms well to the type population except in having higher <i>‘</i> a <i>’</i> ratio (versus <i>‘</i> a <i>’</i> = 18.0 <i>–</i> 19.6); odontophore without basal knobs (versus with small basal knobs, however fig. 3 E of Timm shows only slight basal thickenings of the odontophore rather than distinct basal knobs). The morphology of lip region as per fig. 3 E is rather unusual for a tylencholaimid and may be an error in the drawing. The tail of Indian specimens, though similar to the type, is slightly longer (c <i>’</i> = 1.1 <i>–</i> 1.2 versus 1.0). These minor differences could be attributed to intraspecific variations. <i>Tantunema pakistanense</i> is very close to <i>T. intermedius</i> but differs in the shape of the lip region, shorter gradually expanded pharyngeal expansion (expanded part 33 <i>–</i> 35 % in <i>T. pakistanense</i> versus expanded part 36 <i>–</i> 42 % and pharyngeal expansion being abrupt in <i>T. intermedius</i>); comparatively anterior vulva position (V = 43 <i>–</i> 44 versus 46 <i>–</i> 54). The tail shape is also distinctly different (short, rounded-conoid versus short hemispheroid).
description: Published as part of <i>Ahad, Sumaya &amp; Ahmad, Wasim, 2016, Taxonomy of the genus Tantunema Siddiqi, 1982 (Dorylaimida: Tylencholaimidae) with description of one new and two known species, pp. 1669-1685 in Journal of Natural History 50 (27)</i> on pages 7-10, DOI: 10.1080/00222933.2016.1155670, http://zenodo.org/record/269012
description: {"references": ["Timm RW. 1964. Nematodes of the Superfamily Dorylaimoidea from East Pakistan. Proc. helminth. Soc Wash. 31: 144 - 153."]}