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Skull osteology of Vipera walser (Squamata, Viperidae): Description, variability, ontogeny, and diagnostic characters in comparison to other Italian vipers
Author(s) -
Seghetti Simone Matteo,
Villa Andrea,
Tschopp Emanuel,
Bernardini Federico,
Laddaga Lorenzo,
Fanelli Mauro,
Levi Renzo,
Delfino Massimo
Publication year - 2021
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.21279
Subject(s) - squamata , osteology , viperidae , biology , viper , quadrate bone , ontogeny , zoology , skull , anatomy , morphometrics , intraspecific competition , evolutionary biology , venom , ecology , genetics
Abstract Vipera walser is the most recently recognized European viper. This rare species is endemic to a small area in the Piedmont Alps of Italy, but its closest relatives are found among the Caucasian viper species. In order to provide a starting point for a phylogenetic and biogeographic investigation based on osteology, and including fossils remains, we analyzed four specimens of V . walser and compared them with specimens of the four other Italian viper species. Based on these specimens, we improved the diagnosis of V . walser and provided a first evaluation of intraspecific variability and ontogenetic variation. The skull of V . walser is subject to significant variation, most likely related to ontogeny in some cases (i.e., development of the parietal crest, development of the basioccipital process, shape of the posterior margin of the parabasisphenoid, shape of the quadrate). Based on the studied material, it is possible to distinguish V . walser from the other Italian vipers by the shape of the occipital crest of the supraoccipital, which is posteriorly directed, whereas it is laterally directed in the other species. The osteological diagnosibility provides further support for the validity of V . walser as a distinct species from Vipera berus .