Pungentus clavatus Ahmad & Jairajpuri, 1979

Peña-Santiago, Reyes, Ciobanu, Marcel & Abolafia, Joaquin, 2013, Characterization of Iberian species of the genus Pungentus Thorne & Swanger, 1936 (Nematoda, Dorylaimida, Nordiidae), European Journal of Taxonomy 52, pp. 1-17 : 3-6

Pungentus clavatus Ahmad & Jairajpuri, 1979

Figs 1 A-C, 2

Diagnosis

This species is distinguished by the length of its body (1.37-1.91 mm), the lip region being offset by a constriction and 13-15 μm wide, an odontostyle being 30-35 μm long and 2.3-2.5 times lip region width or 1.7-2.1% of total body length, neck length of 352-437 μm, a pharyngeal expansion 190-221 μm long or 50% of total neck length, a monodelphic-opisthodelphic female genital system, with the anterior genital branch reduced to a very short prevulval sac up to 16 μm long or up to 0.4 times the body diameter, a uterus being a simple tube 101-129 μm long or 2.3-2.8 times the body diameter, V = 39-47, and the female tail being rounded and somewhat clavate (22-31 μm, c = 41-75, c’ = 0.7-1.0).

Material examined

Nine females from two locations, in various states of preservation.

Morphometrics

See Table 1 .

Description

Female

Slender to very slender nematodes of medium size, 1.37-1.83 mm long. Habitus after fixation ventrally curved, especially in posterior body region, G-shaped. Body cylindrical, tapering towards the anterior end. Cuticle two-layered, 2.0-3.0 μm thick in anterior region, 2.0-3.0 μm at mid-body and 4.0-6.0 μm on dorsal side of tail; its outer layer with very fine transverse striation and thinner than inner one. Lateral chord 9-11 µm wide or occupying 21-28% of mid-body diameter, very granular but lacking any differentiation. Ventral body pores perceptible along the entire body. Lip region offset by constriction, 2.2-2.4 times as wide as high and ca. one-third (30-34%) of body diameter at neck base. Lips moderately angular and separate; labial and cephalic papillae distinct, but not especially protruding above cephalic contour. Amphid fovea cup-shaped, opening at level of cephalic constriction, occupying 6.5-8.0 μm or one-half to three-fifths of lip region diameter. Cheilostome almost cylindrical, its walls distinctly thick and sclerotised at the anterior half; perioral refractive dots very conspicuous. Odontostyle 14-18 times as long as wide, 2.3-2.5 times longer than lip region diameter or 1.7-2.1% of total body length; aperture 4.0-5.5 μm long or 12-17% of its length. Odontophore rod-like, almost equal (0.9-1.1 times) to odontostyle. Guiding ring double, located at 20-22 μm or 1.5-1.6 times the lip region diameter from anterior end. Pharynx enlarging very gradually; basal expansion 9.5-12.1 times as long as wide and 5.3- 5.4 times the corresponding body diameter, occupying one-half (50%) of total neck length. Pharyngeal gland nuclei located as follows: DO = 52-53, DN = 54-55, S 1 N 1 = 73, S 1 N 2 = 74, S 2 N = 83-88. Nerve ring at 144-156 μm from anterior end or 36-38% of total neck length. Cardia rounded conoid, 10-11 x 10-11 μm. Genital system monodelphic-opisthodelphic; anterior branch reduced to a short to vestigial, uterine, prevulval sac up to 16 μm long or up to 0.4 body diameters; posterior branch well developed, 180-305 μm long. Ovary 44-218 μm long, often reaching and surpassing the sphincter level; oocytes first in two or more rows, then in one row. Oviduct 77-124 μm long, or 1.9-2.4 times the body diameter, consisting of a slender portion with prismatic cells and a moderately developed pars dilatata. Sphincter distinct between oviduct and uterus. Uterus a simple tube-like structure, 101-129 µm long or 2.3-2.8 times the body diameter. Sperm cells absent within the genital tract. Uterine eggs 96-108 x 36-40 μm. A distinct dorsal cell mass or coelomocyte (see Fig. 2D ) is present at level of oviduct or uterus in two of the specimens examined. Vagina extending inwards 20-25 μm or about one-half (43-54%) of body diameter; pars proximalis almost as long as wide, 13-18 x 12-16 μm, with convergent walls and enveloped by weak circular musculature; pars refringens with two weakly sclerotized pieces; pars distalis 5.5-7.0 μm long. Vulva a pre-equatorial, short transverse slit, which is preceded by a depression of body surface. Prerectum 2.5-2.6 anal body diameters long. Rectum 30-31 μm long, almost equal (0.9-1.0 times) to anal body diameter. Tail short and rounded, more or less clavate. Caudal pores two pairs, one subdorsal, another sublateral, at the middle of tail.

Male

Unknown.

Distribution

Pungentus clavatus was collected from two localities: the province of Jaén (southern Iberian Peninsula), Cazorla, Segura y Las Villas Natural Park Road to Segura river source (38°17’ N - 2°39’ W), in association with pine forest; and the province of Huesca (northern Iberian Peninsula), road from Somport to Huesca (42°34’ N - 0°32’58’’ W), associated to Mediterranean brushwood, with dominant species Buxus sempervirens Linnaeus, 1753 , Juniperus oxycedrus Linnaeus, 1753 , Rosa canina Linnaeus, 1753 , and Rubus sp.

Remarks

Although new data are provided and the ranges of many morphometric features are extended, the present description agrees very well with the original one. In addition to the type locality in India, P. clavatus has been reported from Italy ( Vinciguerra & Giannetto 1987), Poland ( Winiszewska-Slipinska 1987a) and Spain ( Hernández et al. 1988). Winiszewska-Slipinska (op. cit.) also mentioned its occurrence in Canada. No significant interpopulational variation has been reported in this species. The most relevant and characteristic feature of the species is the clavate shape of its caudal region. Pungentus clavatus might be a widely distributed species in the Holarctic.

Figures

Fig. 1. Iberian Pungentus species. – A-C. Pungentus clavatus Ahmad & Jairajpuri, 1979. – D-H. Pungentus engadinensis (Altherr, 1950). – I-K. Pungentus marietani Altherr, 1950. – L-N. Pungentus silvestris Coomans & Geraert, 1962. – A, D, I, L. ♀, anterior region in lateral median view. B, E, J, M. ♀, genital system. C, G, K, N. ♀, posterior body region. F. ♂, posterior body region. H. ♀, caudal region.

Fig. 2. Pungentus clavatus Ahmad & Jairajpuri, 1979 (♀, LM). A-B. Anterior region in lateral median view. C. Pharyngo-intestinal junction. D. Dorsal cell mass at level of uterus. E. Anterior region in lateral surface view. F. Vagina. G. Caudal region. (Scale bars: A, B, E = 20 µm; C, D, F, G = 10 µm)