First record of bicephaly in Lissotriton boscai (Amphibia, Caudata, Salamandridae)

Abstract

Teratologies are frequent among vertebrates, but with differing prevalence among groups. For instance, cases of bicephaly are extremely scarce in amphibians, in contrast with other groups, like reptiles. Here we report the first case of bicephaly in Lissotriton boscai. The anomaly is a consequence of the duplication of the skeleton axis and the subsequent development of most of the cephalic structures in each axis, with heads fused at the level of the cranial post-otic structures. Despite its young age and small size, the larva presents an advanced stage of development. The low frequency of cases of bicephaly among amphibians can be a consequence of high mortality rates in early stages, but it could also reflect differences in the developmental properties between vertebrate lineages.