Meeting Abstract
Numerous phylogenetic studies have addressed squamate (lizard and snake) diversity over the 30 years, typically focusing on osteological data or molecular data. Non-integumentary soft-tissue (NIST) characters are rarely used in these analyses, despite an abundance of descriptive publications. Using published data and new specimen dissections, we constructed a phylogenetic data matrix of 331 NIST characters. Our matrix includes characters addressing skeletal muscle, brain/nervous system, and tongue morphology, among others. We analyzed these data to determine what signal, if any, is provided by these under-used character systems. Although there was limited overlap in character scoring between some groups of taxa, we included 60 squamate species representing 41 “families” (including all of the major squamate clades) in our analysis, and the outgroup Sphenodon punctatus. Our analyses recovered many of the clades traditionally recognized in morphological studies (e.g., Varanoidea). As with recent genetics-based analyses, dibamids are found to be basal within the tree. Unexpected results were also recovered. Macrostomatan snakes were recovered as closely related to teiids based on cranial musculature, hemipenial characters, foretongue division, and spermatozoan microstructure. Xantusia was recovered as a proximal gekkotan outgroup based on eyeball morphology, gross and microscopic tongue morphology, and inner ear microstructure. These and other unexpected results may be more important for understanding ecology/behavior-based convergence than true relationships. Even so, these NIST character systems offer informative data regarding squamate evolution and diversity.
