Acrochordonoposthia vandeputae Houben, Proesmans and Artois n. sp.

(Figs 1 A–F)

Locality. Schloßberg, centre of Graz, Austria (47°04’27”N; 15°26’10”E), in dry mosses (22 August 2011) (TYPE LOCALITY).

Material. Seven specimens studied alive. One whole-mounted specimen designated holotype (SMNH Type- 8567). One whole-mounted, one sagitally-sectioned and one horizontally-sectioned specimen, all paratypes (HU, nos 557–559). Two preserved in 95% ethanol for DNA extraction.

Etymology. Species name dedicated to Ria Vandeput, mother of the first author (AH).

Description. Animals almost 1 mm long. The paired protonephridiopores open ventrally, caudally from the pharynx. The copulatory organ is 63–72 µm long (average 68 µm; measured on two specimens, holotype being the smaller) and is provided with a conical cirral pouch. A large group of eosinophilic, coarse-grained prostate glands opens into the proximal end of the cirrus. This cirrus is 25–35 µm long (average 30 µm; measured on two specimens), is more-or-less straight and covered with spines, which increase in size towards the distal end. A large bursa, about 80 µm long (measured on one specimen), lies next to the copulatory organ. It has a long tubiform proximal part, which is difficult to observe on live animals, and a ±50 µm-long (measured on one specimen), sclerotized, more-or-less cone-shaped distal part. Strong circular muscles surround at least the distal part. We were unable to clearly observe whether or not these also surround the proximal part. A seminal receptacle was not observed.

Diagnosis. Species of Acrochordonoposthia Reisinger, 1924 . Copulatory organ 63–72 µm long. It possesses a straight cirrus, completely covered with spines, which increase in length towards the distal end. Cirral pouch conical. Long bursa, with a tube-shaped proximal part and a cone-shaped distal part and surrounded by circular muscles. Seminal receptacle lacking.