Do skin peptide profiles reflect speciation in the Australian treefrog Litoria caerulea (Anura : Hylidae)?

Abstract

Profiles of skin gland peptides of the tree frog Litoria caerulea from Australia show substantial divergence among geographic locations. Indeed, two divergent groups of populations, ‘eastern’ and ‘northern’, are apparent from a phenetic analysis of similarities of skin gland peptide profiles among populations of L. caerulea. We analyse variation in nuclear genes (allozyme frequencies) and the mitochondrial genome (haplotype relationships and frequencies) to test the taxonomic significance of differences apparent among profiles of skin gland peptides. Both molecular genetic data sets identified the same two groups apparent in the profiles of skin gland peptides. However, neither molecular data set, under an evolutionary species concept, provides strong enough evidence to support recognition of these groups as separate species. These data imply that the genetic basis of the inheritance and expression of skin gland peptides requires further characterisation.