Prionchulus oxycercus Zell 1985

Females (n = 5). L = 2.28-2.63 mm; a = 26-28; b = 3.8-4.1; c = 13-14; c’ = 3.7-4.0; V = 62-64%.

Body large and moderately slender, more or less arcuate ventrally after fixation; 82-98 µm wide at middle. Cuticle smooth, rather thin, 2.5-3.0 µm over all the body. Lip region 42-44 µm wide, lips well developed, conoid. Body at posterior end of oesophagus 1.8-2.0 times as wide as head. Amphid cup-like, small. Buccal capsule (the sclerotized section of mouth cavity) large, 47-48 × 27-28 µm. Dorsal tooth strong with its tip located at 23-26% of the buccal capsule. Sub-ventral ridges with several fine and dense denticles pointing forward. Oesophagus strongly muscular over entire length, 614- 644 µm long. Distance between posterior end of oesophagus and vulva 1.5-1.6 times greater than oesophagus itself. Oesophageal gland nuclei prominent, both AS nuclei lying close to each other: D = 57-60%; AS1 = 54-57%, AS2 = 57-60%, PS1 = 87-90%, PS2 = 88- 91%. Glandularium 230-264 µm long.

Vulva transverse with well sclerotized inner lips. Vagina strong, 34-36 µm long, shorter than half width of corresponding body. Female genital organ of Type I: comparatively short, each ovary more than half as long as corresponding branch of gonads (see Andrássy, 1985: Comments). Genital branches equal in length, 3.0-3.3 body widths long or occupying 11-12% of body length. Tail conoid, ventrally curved, uniformly tapered to its finely sub-digitate, occasionally slightly dorsally curved tip. Tail 176-190 µm long, occupying 7.0-7.5% of entire length of body.

The shape of the tail (sub-digitate on tip) especially characterizes this mononchid species. Winiszewska and Susulovsky (2003) studied the type specimens of Zell (1985) and compared them with other European representatives of the species. At the same time, they synonymized P. oxycercus Zell, 1985 with P. bastiani Zell, 1985, and provided Zell’s P. bastiani – being a homonym of Mononchus (now: Prionchulus) bastiani de Man, 1876 – with the new name P. zelli Winiszewska et Susulovsky, 2003. As I mentioned recently (Andrássy, 2009), this latter action was, however, superfluous since – accepting the synonymization – P. oxycercus has a page priority over P. bastiani, hence the former will be the valid name of the species.

The present specimens fit the descriptions of Zell (1985) on the one hand, and of Winiszewska and Susulovsky (2003) on the other, except for the tail, which is somewhat longer (3.7-4.0 vs. 2.4-3.5 anal body diameters).

Prionchulus oxycercus lives in both terrestrial and aquatic habitats and is seemingly restricted to Europe (Germany, Poland, Czech Republic, Spain and Ukraine). The Albanian specimens were found in a brook at locality No. 6.