Phylogenetic-Relationships Among Australian Tree Frogs (Anura, Hylidae, Pelodryadinae) - an Immunological Approach

Abstract

Phylogenetic relationships among hylid frogs of the Australian region were studied by micro-complement fixation comparisons of serum albumin. Although our data support current species-group arrangements, we do not find good agreement between our phylogenetic hypotheses and those derived from morphological and karyological studies. Immunological analyses provide data which allow the construction of a phylogeny for the Australian radiation of the speciose genus Litoria, and suggest dividing the species of Litoria examined into five major species-assemblages, each of which is probably monophyletic. The sister- group relationship between the Litoria aurea group and Cyclorana is confirmed, and the diphyletic origin of the terrestrial hylids is supported. The radiation of Australian hylids is monophyletic with respect to the outgroup taxon (Hyla) used in this study, and the origin of diversification within the genus correlates well with estimates of the final separation of Australia from Antarctica-South America. Preliminary data suggest that the endemic New Guinean taxa (Nyctimystes and the montane Litoria) are closely related to the Australian 'freycineti' assemblage within Litoria. Albumin from Litoria infrafrenata cross-reacted poorly with all available Australian antisera, suggesting that this species may have originated independently of the rest of the Australian hylids. Our data support the classification of Australian tree frogs as hylids, rather than as leptodactyloid offshoots.