| The Pelobatoidea is the largest, and arguably, the most poorly studied group of basal anurans. Although there are numerous suggestions as to the phylogenetic relationships of the pelobatoids, few agree as to their placement and interrelationships. Because morphological features used in previous analyses did not provide strong resolution of pelobatoid relationships, I conducted phylogenetic analyses of pelobatoids that included more comprehensive data sets, including information from Recent adults, fossil taxa, and larvae. Various data sets were analyzed separately and in combination to determine the utility of each in understanding pelobatoid relationships.; To better understand pelobatoid adult morphology, I described the osteology of Spea multiplicata and compared it to that of several other taxa. These data were coded as phylogenetic characters and used in an analysis of extant pelobatoid relationships. Results support Pelobatoidea and Pipoidea as sister taxa. Within the Pelobatoidea, Pelodytidae is the sister group to Pelobatidae, and Megophryidae is the sister taxon to [Pelobatidae + Pelodytidae].; I also conducted an analysis in which I included most fossil pelobatoids and representative extant taxa. Numerous data points were missing or unknown for many of the fossil taxa. Because this may increase the chance of choosing the incorrect tree and swamps consensus trees with noise, I examined various methods of coding and manipulating characters and taxa and determined the effect and utility of these methods on tree resolution and numbers.; To find additional phylogenetically informative characters, I described the larval skeleton and osteogenesis of Pelobates cultripes and several other pelobatoids. I used these data in a combined analysis of adult and larval characters. Results differ from previous analyses by suggesting that Neobatrachia, rather than pipoids, are the sister group to the pelobatoids. The addition of larval characters greatly improved resolution of the resulting cladogram, specifically at the level of more inclusive taxonomic groups. This suggests that different kinds of data (e.g., developmental patterns versus adult morphologies) may be conserved at different taxonomic levels and that larval information, even if coded for a few representative taxa, can be highly informative in cladistic analyses. |
