Pocillorhynchus spiroductus Schockaert, 1982

Willems, Wim R., Reygel, Patrick, Steenkiste, Niels Van, Tessens, Bart & Artois, Tom J., 2017, Kalyptorhynchia (Platyhelminthes: Rhabdocoela) from KwaZulu-Natal (South Africa), with the description of six new species, Zootaxa 4242 (3), pp. 441-466 : 443-444

Pocillorhynchus spiroductus Schockaert, 1982

( Fig. 1 )

New locality. iSimangaliso Wetland Park , Eastern Shores, Mission Rocks (28°16’44.5’’S, 32°29’08.9’’E), ± 100 m south of footpath to parking lot, algae (mainly small brown algae) taken from the mid-eulittoral in a highlyexposed tidal area with sandstone terrace covered with invertebrates (barnacles, mussels, limpets, corals, tunicates), December 12, 2009.

Known distribution. Somalia, north of Mogadiscio , Hawadli ( Schockaert 1982).

Material. One animal studied alive and whole mounted (HU, no. VII.3.41).

Additional remarks. The general organisation of the specimen from South Africa is completely in accordance with the description given by Schockaert (1982). The specimen is 0.5 mm long (measured on whole mount), transparent to pale reddish-brown and has eyes with “lenses”. The ovovitellaria could not be observed. The hard parts of the male genital system ( Fig. 1 B–C) consist of at least five spines of different length and they most probably form a short cirrus, which is 26 µm long and 19 µm wide at its broadest point in the highly squeezed individual. Schockaert (1982) does not provide any measurements in the description proper, but measured on his Fig. 10, the specimen from Somalia has a copulatory organ comparable in dimensions to that of the South African specimen (22 µm long and 14 µm wide at its broadest). According to Schockaert (1982), the spines are attached to a common base giving the impression of the whole being a single stylet. Although the current material is inadequate to allow any definitive statements, it most probably is a cirrus instead of a single stylet. Also in the two other species of Pocillorhynchus Brunet, 1973 (see Brunet 1973a) the copulatory organ is a cirrus with many spines. The female bursa carries two strongly-coiled insemination ducts ( Fig. 1 A: ba, 1D), which are 14–15 µm long (measured from top to bottom, not axially; i.e. length of the straight line between distal and proximal end of the structure as depicted in Fig. 1 D). This is considerably longer than those of the Somali specimen (8 µm in Schockaert 1982, measured in the same way on his Fig. 10).

Figures

FIGURE 1. Pocillorhynchus spiroductus Schockaert, 1982. A. General organisation (from a live specimen). B-C. Cirrus. D. Insemination duct.