Gordius cf. tatrensis Janda, 1894

Schmidt-Rhaesa, Andreas, 2010, Considerations on the genus Gordius (Nematomorpha, horsehair worms), with the description of seven new species, Zootaxa 2533, pp. 1-35 : 29-30

Gordius cf. tatrensis Janda, 1894

( Fig. 11 A–C)

Material examined. 23 and 1Ƥ from Ukraine, Protsev village, Kiew region (col. April 11, 2002 by A. Khouyak). The specimens are stored in the collection of A. Schmidt-Rhaesa as numbers 623.1–623.3.

Description. The body color is light to medium brown; white spots are present in the male specimens. The anterior end includes a white tip followed by a black collar. The males measure 345 and 360 mm in length and 0.7 and 0.6 mm in diameter, respectively. The female is 435 mm long and has a diameter of 0.7 mm.

The postcloacal crescent is semicircular and directly at the point of bifurcation ( Fig. 11 A). It does not extend much onto the tail lobes. The cloacal opening is round ( Fig. 11 A). The tail lobes are about twice as long as broad, the inner side is slightly concave. Scattered tiny bristles are present on the entire posterior end.

The cuticle is structured into flat polygonal areoles ( Fig. 11 B), no further cuticular structures are present. The cuticle of the female additionally shows numerous short spines arranged more or less in a circle on top of each areole ( Fig. 11 C).

Remarks. The characters of the male specimens correspond to those described for G. tatrensis Janda, 1894 from a source in the Tatra Mountains (locality not further specified; see Janda 1894). This species is documented only by drawings, but the text is detailed enough to mention the structure of areoles, bristles in the posterior end, the form of the cloacal opening and so on. A fine structural reinvestigation of G. tatrensis would help to decide whether the Ukrainian specimens indeed correspond to this species or show differences. One considerable difference is the structure of the areoles in the female. A circle of spines on top of the areoles has not been reported from any species before. Because female and males were found together, it is likely that they are conspecific. If all three specimens represent one species, this is a significant case of sexual dimorphism concerning the cuticle, a character in which other Gordius species usually correspond among sexes.

Figures

FIGURE 11. Schematic drawing indicating the differences in the distribution of bristles and spines in the posterior end of A. G. helveticus, B. G. karwendeli and C. G. zwicki.