Meeting Abstract

30.9  Friday, Jan. 4  Molecular phylogeny and evolution of body size in sub-Saharan puddle frogs (Anura: Phrynobatrachidae) ZIMKUS, B.M.*; HANKEN, J.; Harvard University; Harvard University bzimkus@oeb.harvard.edu

Miniaturization, or the evolution of decreased adult body size, is well documented within the class Amphibia. Although the effects of miniaturization on amphibian skeletal morphology are well known, including loss of skull bones and fusion of phalangeal elements, there is little data regarding evolutionary patterns within large radiations that include both miniaturized and non-miniaturized species. Puddle frogs of the genus Phrynobatrachus constitute a lineage of approximately 70 species that are distributed across sub-Saharan Africa. Adult snout-vent lengths range from 12 mm in some miniaturized species to greater than 40 mm in the largest species. Phrynobatrachus have been a long-standing source of confusion to systematists due to extensive geographic and intrapopulation variation despite only slight morphological differences among species. Therefore, we used molecular data to better resolve species relationships and facilitate analysis of evolutionary patterns. A continuous fragment of approximately 2,350 base pairs of mitochondrial DNA (12S rRNA, valine-tRNA, and 16SrRNA) was collected from approximately 100 individuals of 40 species in order to construct a phylogeny. Body size (snout-vent length) data were obtained from both the literature and direct measurements of museum specimens. Cleared-and-stained whole-mounts and X-rays were examined to identify morphological simplifications, reductions, or novelties within miniaturized species. Results reveal that the basal-most clade includes large-bodied, semi-aquatic species associated with montane forests of eastern Africa. Fusion and reduction of wrist elements from six to four carpals closely follows miniaturization of body size and may be correlated with increased terrestriality. Large body size re-evolves at least once within Phrynobatrachus, although these species retain a wrist configuration with four elements.