Sulla validità specifica di Triturus italicus (Peracca 1898) (Anfibi Urodeli)

Mancino, Giorgio

Atti della Accademia nazionale dei Lincei. Rendiconti della Classe di scienze fisiche, matematiche e naturali, Série 8, Tome 44 (1968) no. 5, pp. 697-700

Résumé

In a revised list of the European Amphibians and Reptiles by Mertensand Vermuth (1960), the salamander Triturus italicus has been considered to be a sub-species of Triturus vulgaris. Actually the recognition of the species on the morphological ground alone cannot be considered final. However the morphological similarity between italicus and vulgaris is not associated with the ability to form hybrids in nature. Only few hybridscan be produced in the laboratory: in fact the number of fertilized eggs is very low and the mortality is great during the early part of embryonic development. Moreover the adult hybrids of the cross vulgaris ♀ X italicus ♂ and the majority of those produced in the reverse cross were females. Hybrid gonads are generally poorly developed: few oocytes grow and accomplish the vitellogenesis in the ovaries; male meiosis stops at meta-anaphase I owing to severe karyological abnormalities. Also detailed karyological researches on mitotic and mainly on lampbrush chromosomes have shown remarkable differences between the karyotypes of T. italicus and T. vulgaris, confirming their great divergence at the genetic level. Therefore, considering the morphological and the hybridological criteria and the karyological differences as well, Triturus italicus and T. vulgaris appear to be two well differentiated species.