Taxonomy, phylogeny and biogeography of reptiles—Problems of cladistic taxonomy

Abstract

In the studies of reptiles, I started the study of phylogeny and biogeography of the scincid genus, Plestiodon (formerly Eumeces) in the East Asian Islands by cladistic analysis and neighbor joining method based on morphological data. Then our laboratory has continued to study this group genetically using allozymes and DNA data. We revealed the process of the speciation of the genus in Japanese and Ryukyu Archipelagos. During the studying this group, we described five cryptic species. While studying the taxonomy and phylogeny of reptiles, I found that the cladistic taxonomy has several problems. I proposed the gradistic classification system showing cladistic relationship by putting a tag of the descendant grade within the ancestral grade.