Developmental changes through an animal's life are generally understood to contribute to the resulting adult morphology. Possible exceptions are species with complex life cycles, where individuals pass through distinct ecological and morphological life stages during their ontogeny, ending with metamorphosis to the adult form. Antagonistic selection is expected to drive low genetic correlations between life stages, theoretically permitting stages to evolve independently. Here we describe, using Australian frog radiation, the evolutionary consequences on morphological evolution when life stages are under different selective pressures. We use morphometrics to characterize body shape of tadpoles and adults across 166 species of frog and investigate similarities in the two resulting morphological spaces (morphospaces) to test for concerted evolution across metamorphosis in trait variation during speciation. A clear pattern emerges: Australian frogs and their tadpoles are evolving independently; their markedly different morphospaces and contrasting estimated evolutionary histories of body shape diversification indicate that different processes are driving morphological diversification at each stage. Tadpole morphospace is characterized by rampant homoplasy, convergent evolution and high lineage density. By contrast, the adult morphospace shows greater phylogenetic signal, low lineage density and divergent evolution between the main clades. Our results provide insight into the macroevolutionary consequences of a biphasic life cycle.

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-Embryonic and larval development of the seven Geocrinia species across Australia are described and compared. This Australian myobatrachid genus includes three species with terrestrial embryonic development followed by aquatic exotrophic larval development and four species with entirely terrestrial and endotrophic development. Comparisons are made among species within the terrestrial/exotrophic group and the endotrophic group, and between the two breeding modes of each different species-group. Morphological differences are noted between northern and southeast coastal Western Australian populations of G. leai tadpoles. The G. rosea group shares some similarities with the other Australian endotrophic species in the genus Philoria and Crinia nimbus.

Ecomorphology is the association between an organism's morphology and its ecology. Larval anuran amphibians (tadpoles) are classified into distinct ecomorphological guilds based upon morphological features and observations of their ecology. The extent to which guilds comprise distinct morphologies resulting from convergent evolution, the degree of morphological variability within each guild, and the degree of continuity in shape between guilds has not previously been examined in a phylogenetically informed statistical framework. Here, we examine tadpole ecomorphological guilds at a macroevolutionary scale by examining morphological diversity across the Australian continent. We use ecological data to classify species to guilds, and geometric morphometrics to quantify body shape in the tadpoles of 188 species, 77% of Australian frog diversity. We find that the ecomorphological guilds represented by Australian species are morphologically distinct, but there is substantial morphological variation associated with each guild, and all guilds together form a morphological continuum. However, in a phylogenetic comparative context, there is no significant difference in body shape among guilds. We also relate the morphological diversity of the Australian assemblage of tadpoles to a global sample and demonstrate that ecomorphological diversity of Australian tadpoles is limited with respect to worldwide species. Our results demonstrate that general patterns of ecomorphological variation are upheld in Australian tadpoles, but tadpole body shape is more variable and possibly generalist than generally appreciated.