Morphological Correlates of Limaxivory in <i>Contia</i> (Serpentes: Dipsadinae) Compared to Related Taxa <i>Carphophis</i> and <i>Diadophis</i>

Differences in the skull and musculature of snakes can often be linked to their diet. Snakes that eat snails and slugs have evolved independently at least four times. Several skull features of the skull have already been reported in snakes that eat snails, specifically those in the genus Pareas and some Dipsadini. Among those features are a shorter, more compressed snout and, in some species, asymmetry of the lower jaw. However, little attention has been paid to snakes that specialize only on slugs (limaxivores). Unlike the snail-eating members of the Pareidae and Dipsadini, limaxivores lack the morphological traits associated with the extraction of snails from their shells. In Chapter Two, I used microCT imagery of skulls to examine the anatomical basis for limaxivory in two species of the genus Contia. Their skulls were compared to those of Carphophis amoenus and Diadophis punctatus. Although not always considered to be the closest relatives of Contia, Carphophis and Diadophis are nonetheless members of the same general lineage as Contia, and are the most appropriate species for anatomical comparisons to determine what specializations may exist in Contia for the consumption of slugs. I observed substantial differences between the genera, presumably reflecting differences in feeding, how they utilize their habitat, and their small size. In Chapter Three, I report the results of diceCT, which uses stained tissues to compare the musculature of carphophiin snakes. Additionally, I describe the morphology and cellular composition of the glands in the head of C. tenuis. In both the bones and muscles of the head, modifications associated with burrowing were clearly apparent in Carphophis. The anatomy of the glands in Contia tenuis was less similar to other dipsadines than had been expected. The morphology and staining of the sublingual gland were the most unexpected aspect of the glandular analysis.