Phylogenetic Relationships Within the Australian Sphenomorphus Group (Squamata: Scincidae) and the Study of Limb Reduction

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9707428 Reeder The scincid lizards of the Sphenomorphus group include at least 210 recognized species and represent a dominant component of the Australian herpetological (amphibian and reptile) fauna. These lizards are characterized by extensive variation in reduction of limbs: eight of the fourteen described genera contain species that exhibit limb reduction, ranging from loss of a single phalange (a bony element in a finger or toe) to complete limblessness. Tod Reeder of the University of San Diego will employ DNA sequences from the mitochondrially-encoded 12S and 16S ribosomal (r)RNA genes to assess genealogical relationships among over 70 Sphenomorphus species and allies. He also will examine a suite of morphological characters, derived primarily from osteological structures and scales. These data will be used to generate a genealogy of the species, in part to generate a natural classification. The patterns of limb reduction in these species will be assessed from within the context of the genealogy in order to determine the number of times and trajectories of limb reduction and to determine the life-history traits associated with these morphological changes. Relative rates of limb reduction between fore- and hind-limbs also will be assessed. Results from this project will improve understanding of lizard phylogeny, provide empirical information on the utility of reductive characters in lizard phylogeny and biology, and contribute a necessary framework for the investigation of other biological and ecological attributes.