Correlation of ventricle mass and dehydration tolerance in amphibians

We utilized a variety of standard and phylogenetic contrast regression techniques to investigate the relationship between ventricle mass of preserved male specimens and reported dehydration tolerance for a variety of amphibian species. There were significant correlations between arcsin-transformed relative ventricle mass (percent of body mass) and relative dehydration tolerance (percent of body mass) for all amphibians, for all anurans, and for all neobatrachians. The residuals of the log-log regressions relating ventricle mass and mass lost at dehydration tolerance point with body mass were significantly correlated, again for all amphibians, for all anurans, and for all neobatrachians. The results of the phylogenetic regressions parallel the results of the standard regressions, though two species determine the relationship We conclude that ventricle mass and dehydration tolerance are correlated in neobatrachian anurans and suggest a mechanism for their coevolution. An important consequence of this study is the potential use of morphologic measurements of museum specimens for screening of extreme tolerance or vulnerability of a species to stress, without having to perform lethal physiological experimentation on live animals.