Twenty-Third Annual Meeting and Symposium of the
Desert Tortoise Council, April 3-5, 1998
Abstracts

Stratophenetic and cladistic phylogenetic analyses have given differing phylogenies for the tortoise genus Gopherus. A stratocladistic analysis maximizing both character and stratigraphic parsimony is here presented for both living and fossil species. Two clades, one containing the extant Gopherus polyphemus and G. flavomarginatus, and another containing the extant G. berlandieri and G. agassizii can be recognized. Recognition of these two clades is contra previous cladistic analysis of morphology, but supports the phylogeny based on mitochondrial DNA. The recognition of these two clades may have taxonomic implications. Stratocladistic analysis also provides a more resolved tree than cladistic analysis for the fossil species.