Polycystis

Faubel, A. & Warwick, R. M., 2005, The marine flora and fauna of the Isles of Scilly: Free-living Plathelminthes (‘ Turbellaria’), Journal of Natural History 39 (1), pp. 1-45 : 31-33

Polycystis sp. ( P. naegelii group)

( Figure 8C )

Material examined

Sites 5, 15: two specimens, in squash preparation.

Description

Length of body in squash preparation 1.0 mm. Two pairs of eyes, i.e. two crescent eyes at each side being very far from each other. Mid-dorsally, band of pigmented dark red-brown reticulated lines running from anterior end to rear end. The pigmented band broad anteriorly, becomes smaller caudad. Colour of body dirty grey. Pharynx behind proboscis in horizontal plane. A sclerotized stylet marks the transition of the distal part of the prostatic vesicle into the atrium. The stylet looks like a bottleneck with a thick-ended collar and a lateral pointed projection; teeth absent ( Figure 8C ). The measurements of the stylet are: diameter of distal opening 17.8 M m, diameter of proximal opening 25.8 M m, distance between distal and proximal opening 12.5 M m and length of lateral projection 6.5 M m.

Remarks

In total, four specimens of the Polycystis naegelii group ( Karling 1986) were found, two specimens of which could definitely be determined as Polycystis naegelii Kölliker based on the following characters given by Evdonin (1977) and Karling (1986): body length up to 3.5 mm, two eyes, colour dirty greyish black, and stylet with single flagellum directed caudad. Both the other specimens differ in the following characters: length of body of sexually mature specimens 1.0 mm, two bilateral pairs of eyes, band of dark red-brown reticulated lines dorsally, and stylet with a short projection directed laterad. Evdonin (1977) stated that Polycystis naegelii has stylets with either a smooth collar, with teeth along the collar, or with one or two flagella of different size at the collar. The authors are convinced that these different forms of the stylets represent different species, as do the present species. But the authors must desist from the establishment of a new species within the Polycystis naegelii group because the sagittally sectioned series is damaged so that the reconstruction of the genital system is impossible.

Paulodora riedli ( Karling 1956) Artois and Schockaert, 1998 Polycystis riedli Karling, 1956: 230–233 , Figures 40–44, 51–52.

Material examined

Site 7: one specimen in squash preparation.

Geographical distribution. Mediterranean Sea: Gulf of Lion, Ligurian Sea, Tyrrhenian Sea, Adriatic Sea ( Riedl 1959b; Brunet 1965).

Figures

Figure 8. Scilliυortex phytophilus gen. et sp. nov. (A) Dorsal view in squash preparation; (B) sclerotized male stylet. Polycystis sp. (C) sclerotized male stylet. Scale bars: 250 Mm (A); 50 Mm (B); 10 Mm (C).