Date of Award


Document Type


Degree Name

Master of Science




The Pipoidea are a diverse group of frogs. Their diversity is demonstrated in their morphology, ecology, and behavior. One pipoid species, Xenopus laevis, has been used as a model system of developmental, physiological, and molecular studies of vertebrates. My work has focused on the developmental morphology of the chondrocranium and oral morphology of four pipoid taxa: Hymenochirus boettgeri, Rhinophrynus dorsalis, Pipa carvalhoi, and Xenopus laevis. Previous studies have suggested that the Anura may be diphyletic based on the unique characteristics of the chondrocanial morphology of pipoids. The chondrocranial and internal oral morphology of the pipoids indicates that as a group as weH as individual species the Pipoidea are highly derived. However, the present study shows that the ethmoidal region of the Pipoidea is homologous to that of other Anura, refuting the proposed diphyletic origin of the Anura. An evaluation of chondrocranial characters in phylogenetic reconstruction is presented.

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