Planorbis cretensis Glöer & Hirschfelder 2015, n. sp.

(Fig. 1)

Type series. Holotype (ZMH 79836): Shell height 2.9 mm, shell width 1.0 mm; Paratypes (ZMH 79837): 3 specimens from type locality (coll. Glöer 1 ad., coll Hirschfelder 5 ad., 9 juv.).

Locus typicus. Greece, Topolia, 9 km south of Kissamos, W-Crete, spring in village, 35°25'46.4" N, 23°41'07.1" E, alt. 260 m asl., 16.10.2014 Andrea and Hans-Jürgen Hirschfelder leg.

Description

Shell: The horn-coloured shell is glossy, finely striated, and the 3.5 whorls increase regularly. The whorls are on the upper side regularly convex with a deep suture, on the underside the whorls are slightly flattened. The first whorls on the upper side are deep and the underside is widely umbilicated. The aperture is oval and not deflected. The diameter of the shell is 2.8-3.0 mm, and the height of the last whorl is 0.9-1.0 mm.

Animal: The animal is light grey, the mantle pigmentation is light and without patterns.

Anatomy: The preputium is dorsal dark pigmentated, the penis sheath is twice to three times longer than the preputium, and as slender as the vas deferens. The prostate gland bears 18-20 diverticula. The bursa is of tadpole type with a thin bursa duct.

Etymology. Named after the island where the species was found.

Differentiating features. The new species from Crete can be distinguished from Planorbis moquini and P. agraulus by the number of prostate diverticules (11-13 in P. moquini and 18-24 in P. agraulus, data taken from Glöer & Zettler (2009) and Glöer & Bouzid (2008) respectively). In P. moquini the mantle is dark grey, while in P. agraulus and in P. cretensis n. sp. it is light. The whorls in P. agraulus are more convex, especially on the underside, as in P. cretensis n. sp.

Habiat. The species was found to live on dead leaves in a captured spring (Fig. 2) beside the main road in the village Topolia together with Pseudamnicola brachia (Westerlund, 1886).

Distribution. Crete; known only from the locus typicus.