Adenocerca minima Kolasa, 1981

Houben, Albrecht M., Monnens, Marlies, Proesmans, Willem & Artois, Tom J., 2022, Limnoterrestrial ‘ Typhloplanidae’ (Rhabdocoela, Platyhelminthes), with the description of four new species and a new genus, European Journal of Taxonomy 798, pp. 70-102 : 79-80

Adenocerca minima Kolasa, 1981

Fig. 4

Material examined

AUSTRIA • 3 specs, studied alive, one of which whole mounted and a second one horizontally sectioned; south of Graz, between Glashütten and Trahütten; 46°49′46″ N, 15°06′09″ E; 23 Aug. 2011; A.M. Houben and W. Proesmans leg.; humid moss from a small stream in a pine forest; XIV.2.38 and XIV.3.18; HU.

Description and discussion

Specimens are about 0.6 mm long. Habitus and internal organisation correspond to the description of Kolasa (1981b). However, the original description, based on one specimen, mentions a much smaller animal (0.3 mm) (see Kolasa 1981b). Small dermal rhabdites are present all over the body. Protonephridiopores ( Fig. 4A : pp) are situated lateral to the pharynx ( Fig. 4A–B : ph). The two small testes ( Fig. 4A–B : t) are situated caudally from the pharynx, at 65–70% of the body.

Adenocerca minima clearly differs from all other representatives of Adenocerca by the orientation of the spines of its copulatory organ (see Fig. 4C–F ). Small spines are present in the distal half of the cirrus and at the distal end, where 6 µm long, distally pointing, crescent-shaped spines form a crown ( Fig. 4C : cs). Other species only possess small spines (A. clinopharynx Reisinger, 1924 and A. teshirogii) or have a different orientation of these spines, with the proximal spines being the biggest (A. bresslaui Reisinger, 1924).

Remarks

Kolasa (1981b) mentioned seven crown spines while we only counted six. Both Kolasa’s and our counts were made on a single specimen. Therefore, for the time being, we prefer to designate our specimens to the same species as Kolasa’s (1981b).

Previously known distribution

In wet mosses on the banks of the stream Fosso Contesora, Italy ( Kolasa 1981b).

Figures

Fig. 4. Adenocerca minima Kolasa, 1981. A. Internal organisation of a live specimen. B. Reconstruction of reproductive organs based on horizontal sections. C–F. Male copulatory organ of the whole-mounted specimen (XIV.3.18).