SHEIL, C.S.: Amniote Phylogeny Inferred from Morphology

Phylogenetic relationships among living and fossil amniotes remain uncertain, and the topic is among the most contentious in evolutionary biology. Numerous evolutionary hypotheses supported by molecular and morphological data have been published recently. Previously, I presented results of a collaboration that combined the largest set of morphological and molecular data. Here, preliminary results of an expanded morphological data set (i.e., incresed taxon and character sampling) are presented. Extant taxa represent six amniote lineages (birds, crocodilians, mammals, rhynchocephalians, squamates, and turtles). Extinct taxa represent several fossil lineages: Captorhinidae, Procolophinidae and Pareiasauridae (non-turtle anapsids); Petrolacosaurus and Araeoscelis (early diapsids); Mesosauridae; and several non-mammal synapsids. Additional taxa and characters will be added. Relative congruence among alternate phylogenetic hypotheses, taxon and character sampling, and missing data will be discussed.