Proteus anguinus anguinus Laurenti , 1768 Proteus anguinus parkelj Sket & Arntzen, 1994
The olm or proteus ( Proteus anguinus ) is an aquatic salamander which is the only species in the genus Proteus of the family Proteidae [2] and the only exclusively cave-dwelling chordate species found in Europe; the family's other extant genus is Necturus . In contrast to most amphibians , it is entirely aquatic , eating, sleeping, and breeding underwater. Living in caves found in the Dinaric Alps , it is endemic to the waters that flow underground through the extensive limestone bedrock of the karst of Ce
This cave salamander is most notable for its adaptations to a life of complete darkness in its underground habitat. The olm's eyes are undeveloped , leaving it blind, while its other senses , particularly those of smell and hearing , are acutely developed. It also lacks any pigmentation in its skin . It has three toes on its forelimbs, but only two toes on its hind feet. It exhibits neoteny , retaining larval characteristics like external gills into adulthood, [5] like some American amphibians, the axolotl