Paromalostomum minutum Rieger, 1971

Schockaert, Ernest R., 2014, Marine Macrostomorpha (Platyhelminthes, Rhabditophora) from the Algarve (Southern Portugal), Zootaxa 3872 (5), pp. 577-590 : 582-583

Paromalostomum minutum Rieger, 1971

Fig. 4

Localities in the Algarve. From the same samples in which P. dubium was found.

Known distribution. So far, this species is known only from the type locality, Venice ( Italy), Lido di Alberoni around the low-water level in shallow water and in a tidal beach pool; clean fine sand.

Material. one whole mount (HU nr. VI.3.23).

The penis stylet is 150 µm and the accessory stylet 62 µm long (or around 60 µm), resp. 100–120 µm and 55–65 µm in the description of Rieger (1971b). The very end of the penis stylet makes a turn of almost 360° and is not surrounded by the thickened sheath of the terminal part. The accessory stylet has a proximal diameter of 6 µm and a sharp and curved terminal end. In the female hard parts the sperm tube is 184 µm and the mouthpiece 22 µm long (about 8 µm in Rieger’s material). The middle piece is a comma-like plate (about 20 µm long) with a thickened outer side with teeth-like knobs.

A B c st Ds

mi ps mp Αf Β

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Along with P. minutum, Rieger (1971b) also described P. parvum , from the same samples, with hard parts very similar in form and size. The only differences are that the penis stylet in P. parvum does not show a twisted end, and that the middle piece of the female hard parts is smooth without the teeth-like knobs. Also P. massiliensis Rieger, 1971 , from the Marseille area, has hard parts looking like those in P. minutum , but has an accessory stylet about twice as long.