The chondrocrania of North American Rana larvae (Anura: Ranidae): a morphological comparison

Abstract

AbstractA detailed morphological description of the chondrocranium is provided for the larvae of six species of North American Rana. Results indicated that although qualitative variation in chondrocranial morphology was limited among the larval Rana examined here, R. sylvatica is clearly distinguishable from other species based on the presence of a shorter articular process of the palatoquadrate, a wider muscular process of the palatoquadrate, and a more posterior position of attachment of the larval otic process to the palatoquadrate. These conditions are similar to those found in the Eurasian R. temporaria. Rana clamitans and R. catesbeiana are distinguished by a considerably narrower palatoquadrate in the region posterior to the anterior quadratocranial commissure, a more anterior position of attachment of the larval otic process to the palatoquadrate, and the presence of a lateral trabecular process in some specimens. These characters may represent larval synapomorphies for the traditional R. catesbeiana group (=Aquarana).