The unexpectedly dull tadpole of Madagascar’s largest frog, <em>Mantidactylus guttulatus</em>

Abstract

The Madagascar-endemic mantellid genus Mantidactylus contains one subclade with two described frog species characterized by very large body sizes. This subclade is classified as the subgenus Mantidactylus and is widespread in eastern and northern Madagascar, but their reproductive biology and larval stages are still unknown. We here provide a detailed description of the larvae of one species in this subgenus, M. guttulatus, on the basis of genetic assignment (16S DNA barcoding). The tadpoles were collected in the dry season from shallow waters near a stream in the Mahajanga Province in northwestern Madagascar. Their body and tail shape is remarkably generalized as typical for stream-adapted tadpoles, and the oral disc and labial keratodont row formula (4(2-4)/3(1)) are similar to those of other lotic mantellid frog larvae with generalized mouthparts like those in the subgenus Brygoomantis. The well-separated positions of these subgenera in the mantellid phylogeny suggest extensive homoplasy in the evolution of larval mouthpart morphology within Mantidactylus.