Crenobia alpina (Dana, 1776)

Crenobia alpina is restricted to the Gennargentu Massif (central-eastern Sardinia) (Fig. 3). Up to now, five sexual populations of this European stenotherm species have been found at many cold springs, with temperatures ranging from 7 C° to 15 C°, at altitudes ranging from 1300 m to 1800 m asl. The first record dates back to 1980 when Pala et al. collected specimens from four stations. Besides a morphological study, these workers performed also preliminary karyological analyses, revealing a polyploid karyotype with a marked tendency to aneuploidy, with a mitotic chromosome number ranging from 28-30 to more than 40 (Pala et al., 1980c).

All populations are characterized by a single pharynx and thus differ from the polypharyngeal forms C. alpina montenigrina (Mràzek, 1904), C. alpina anophtalma (Mràzek, 1907), and C. alpina teratophila (Steinmann, 1908) (Pala et al., 1980c; Stocchino et al., 2013c).