Visceral vasculature in the family Cordylidae (Reptilia: Squamata)

Abstract

Major circulatory patterns in lizards of the family Cordylidae are poorly known, but may serve as a source of characters for systematics. Two specimens each of the cordylines, Cordylus jordani and C. pofyzonus, and the gerrhosaurine, Zonosaurus madagascariensis were prepared by Microfil™ injection and whole body clearing and staining to serve as the basis for a comparison of cordylid visceral vasculature. The greatest amount of variation within the family is seen in the vessels of the hepatic portal system, whereas venous drainage and the arterial system (exclusive of the coeliac artery and its branches) are largely conservative within the group. Despite extensive homoplasy in lizards as a whole, cordylids (sensu lato), and especially gerrhosaurines, share a number of features of vasculature that support their sister-group relationship to the Scincidae. The proximity of the origin of the anterior and posterior mesenteric arteries stands as a putative synapomorphy of cordylines + gerrhosaurines. Features of the hepatic portal drainage may be autapomorphic for the genus Cordylus or for cordylines as a whole.