Pungentus silvestris (de Man, 1912 )

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 : 12-14

Pungentus silvestris (de Man, 1912)

Figs 1 L-N, 6

P. thornei Goodey, 1943: 6 , figs 1-6.

Diagnosis

This species is characterized by the length of its body (1.50-2.20 mm), the lip region being offset by a constriction and 12-18 μm wide, an odontostyle being 30-38 μm long and 2.3-2.7 times lip region width or 1.7-1.9% of total body length, neck length of 366-507 μm, a pharyngeal expansion 160-247 μm long or 46-56% of total neck length, a mono-opisthodelphic female genital system, a uterus being a simple tube 98-124 µm long or 2.1-2.7 times the body diameter, V = 39-46, and the female tail rounded (26-34 μm, c = 43-90, c’ = 0.7-1.0).

Material examined

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

Morphometrics

See Table 1 .

Description

Female

Slender nematodes of medium size, 1.65-2.10 mm long. Habitus after fixation ventrally curved, especially in posterior body region, C- or G-shaped. Body cylindrical, tapering towards the anterior end. Cuticle three-layered, 2.0-3.0 μm in anterior region, 2.5-3.0 μm at mid-body and 6.0-8.0 μm on dorsal side of tail; its outer layer with very fine transverse striations and intermediate layer distinctly thicker than inner and outer ones. Lateral chord 10-13 µm wide or occupying one-fifth to one-fourth (19-24%) of mid-body diameter, very granular but lacking any differentiation. Lateral pores obscure in the specimens examined; ventral pores well perceptible ( Fig. 1N ) along the entire body. Lip region offset by constriction, 2.1-2.6 times as wide as high and ca. one-third (29-35%) of body diameter at neck base. Lips mostly amalgamated and rounded; labial and cephalic papillae distinct, but not especially protruding above cephalic contour. Amphid fovea cup-shaped, opening at level of cephalic constriction, occupying 8-9 μm or about three-fifths (55-62%) of lip region diameter. Cheilostome almost cylindrical, its walls distinctly thicker and sclerotized at the anterior half; perioral refractive dots or platelets very prominent. Odontostyle 12.2-14.8 times as long as wide, 2.1-2.4 times longer than lip region diameter or 1.7-1.9% of total body length; aperture 4.0-5.5 μm long or 13-18% of its length. Odontophore rodlike, hardly shorter (0.9 times) than odontostyle. Guiding ring double, located at 21-23 μm or 1.6 times the lip region diameter from anterior end. Pharynx enlarging gradually; basal expansion 7.3-9.6 times as long as wide and 4.4-5.6 times the corresponding body diameter long, occupying about one-half (48-56%) of total neck length. Pharyngeal gland nuclei located as follows: DO = 48-52, DN = 50-54, S 1 N 1 = 71, S 1 N 2 =?, S 2 N = 88-89. Nerve ring at 124-160 μm from anterior end or 31-37% of total neck length. Cardia rounded conoid, 13-18 x 14-17 μm. Genital system monodelphic-opisthodelphic. Anterior branch reduced to a very short pre-vulval, uterine sac 8-17 μm long or less than half (0.2-0.4 times) the body diameter. Posterior branch well developed, 176-498 μm long: ovary 98-240 μm long, with oocytes first in two or more rows, then in one row; oviduct 75-122 μm long, or 1.7-2.3 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 apparently a simple tube 98-124 µm long or 2.1-2.7 times the body diameter. Vagina extending inwards 23-27 μm or about one-half (50-58%) of body diameter; pars proximalis almost as long as wide, 14-17 x 12-14 μm, with convergent walls and enveloped by weak circular musculature; pars refringens with two weakly sclerotized pieces, 3.5-4.0 x 5 μm, and with a combined width of about 9-10 μm; pars distalis 3.0-3.5 μm long. Vulva a pre-equatorial, short transverse slit, preceded by a depression of the body surface. A prevulval, gland-like structure (‘paravulva’) present in one specimen ( Fig. 6I ). Prerectum 3.1-3.7, rectum 0.8-1.2 anal body diameters long. Tail short and rounded. Caudal pores two pairs, one sublateral, another subdorsal, at the middle of the tail.

Male

Not found.

Distribution

This species has been collected from two locations in the southern Iberian Peninsula: the province of Jaén, Cazorla, Segura y Las Villas Natural Park, near the road to the Segura river source (38°17’ N - 2°39’ W), in association with pine forest; and the province of Granada, Sierra Nevada National Park, near the road from Capileira to Veleta (36°57’ N - 3°21’ W), in a pine forest and among herbaceous plants where the dominant species was Asphodelus albus Miller, 1768 .

Remarks

The present description fits those available from the literature. It agrees especially well with the redescription of the species by Coomans & Geraert (1962). These authors regarded P. thornei Goodey, 1943 as a junior synonym of P. silvestris , an action that seems to be totally justified and herein accepted.

Pungentus silvestris might be a cosmopolitan species. It has been reported from many European countries such as Belgium ( Coomans & Geraert 1962), Bulgaria ( Ilieva et al. 1993), Denmark ( Yeates 1972, as P. thornei ), Germany ( Altherr 1968, as P. thornei ), Italy ( Marinari et al. 1980), Poland (Winiszewska- Slipinska 1987), Russia ( Skarbilovich & Ovsjukova 1989), Spain ( Monreal & Campoy 1982, as P. thornei ), The Netherlands (de Man 1912; Coomans & Geraert 1962; Bongers 1988) and United Kingdom ( Goodey 1943, as P. thornei ).

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. 6. Pungentus silvestris (de Man, 1912) (♀, LM). A-C. Anterior region in median lateral view. D. Lip region in surface lateral view. E, I. Vagina and pre-vulval uterine sac. F-G: Posterior genital branch. H. Pharyngeal expansion. J. Caudal region. (Scale bars: A-E, I, J = 10 µm; F-H = 50 µm)