Comprehensive DescriptionRead full entry
Costal grooves well-developed, 11-12 on each side of the body. Body elongated and slender. Tail usually longer than body with head. Adults are able to autotomize and regenerate the tail. Coloration black, dark-brown or brown-orange with oval yellow dorsal and lateral spots arranged in two more or less regular rows. Belly brownish. The extent of the yellow spot development is subject to variation. In contrast to females, the males possess a spike-shaped protuberance on the dorsal surface of the tail base and nuptial pads on the forelegs which are best developed during the breeding season. Mertensiella caucasica displays a high extent of morphological and, probably, genetic polymorphisms. In particular, specimens from Mtirala Mountain near Batumi Town, Georgia, have light, earthworm-like coloration and spots are reduced. There are also some altitudinal variations in the salamander morphometrics, including coloration, body proportions, etc.
The two species in the genus Mertensiella, M. caucasica and M. luschani, are not sister taxa based on molecular sequence data. Some authors recommend including M. luschani in the genus Salamandra, while M. caucasica is more closely related to Chioglossa lusitanica. See Titus and Larson (1995) and Veith et al. (1998) for phylogenetic analyses and discussion.