A MORPHOLOGICAL AND BIOLOGICAL ASSESSMENT OF CRENOBIA ALPINA AND CRENOBIA MONTENIGRINA IN PARÂNG-CARPATHIAN MOUNTAINS (ROMANIA), (PLATYHELMINTHES, TRICLADIDA, PLANARIIDAE)

The paper analyses the morphology of the copulatory apparatus and the reproductive isolation of the monopharyngeal and polypharyngeal Crenobia (Dana, 1766) in sympatric populations in Parâng Mt., Romania. The copulatory apparatus of the two forms shows a non-simultaneous development, indicating a seasonal reproductive isolation: the monopharyngeal alpina becomes able to mate during the warm season while the polypharyngeal montenigrina becomes able to mate during the cold season. The mature copulatory apparatus of the monopharyngeals and the polypharyngeals shows all the characters typical for Crenobia alpina (Dana, 1766), respectively for Crenobia montenigrina (Mrázek, 1904) as presented in the literature. In both species, some specimens reveal a complex system of fine ducts / sclerotized lines into the wall of the genital atrium, which are attributed to biological structures of unknown function rather than histological artefacts.