Evolution of Viviparity in Salamanders (Amphibia, Caudata)

Abstract

Reproductive modes in salamanders (Amphibia, Caudata) are highly diverse. Viviparity, for instance, implies the retention of the developing embryos inside the females until the end of the gestation, at which point they deliver fully developed terrestrial juveniles. From an ecological point of view, the evolution of viviparity is highly significant, since it implies the semi-independence of water for an amphibian. Nevertheless, viviparity is not very common among salamander. It has independently evolved only in a few species, all included within the family Salamandridae. Furthermore, the characteristics of viviparous strategies are different among species, although they all share some commonalities. The detailed study of these particular and common features in a phylogenetic context will reveal the genetic, physiological, developmental, morphological, and historic factors that have triggered the evolution of this peculiar mode of reproduction in only one lineage among all the species of salamanders