Molecular systematics and biogeography of the fanged frogs of Southeast Asia.

Our analysis of parts of the mitochondrial ribosomal 12S and 16S genes from 39 populations of Southeast Asian ranid frogs confirms that the fanged frogs are a monophyletic clade. This group, properly called Limnonectes, appears to have arisen in the early Tertiary at a time when free faunal exchange was possible among Southeast Asia, Borneo, Sumatra, Java, and, probably, Sulawesi. Four species groups are tentatively identified within the clade. Part of group 1 includes species related to L. kuhlii that occur in Borneo. Another part of group 1 includes species from Malay Peninsula and Thailand that are related to L. pileata. Species group 2, L. leporina, occurs only in Borneo. Species group 3 is restricted to species distributed in Sulawesi and the Philippines. Species group 4 includes L. blythii and relatives. There is a lack of compatibility between phylogenetic hypotheses generated from molecular and morphological data sets. These differences are related, in large part, to whether some species of Limnonectes have secondarily lost fangs or whether lack of fangs represents the primitive condition.