Length-mass allometries in amphibians

Area of Science:

• Herpetology
• Ecology
• Evolutionary Biology

Background:

• Body mass is a crucial metric in ecological and evolutionary studies but is infrequently measured in amphibians.
• Snout-to-vent length (SVL) is commonly used as a proxy for body mass, but this can be problematic in comparative analyses involving diverse taxa and morphotypes.

Purpose of the Study:

• To develop and validate allometric relationships for estimating amphibian body mass from SVL measurements.
• To assess if these relationships vary based on habitat preference and morphotype within frogs and salamanders.

Main Methods:

• Phylogenetic generalized least squares models were fitted using SVL-mass data from 88 frog (Anura) and 42 salamander (Caudata) species.
• Allometric relationships were analyzed separately for frogs and salamanders, and for specific families.
• Models were tested for differences across habitat preferences (semi-aquatic, terrestrial, arboreal) and salamander morphs (paedomorphic, non-paedomorphic).
• Predictive performance was evaluated using cross-validation.

Main Results:

• The developed allometric models demonstrated high explained variance and low forecasting errors.
• Significant differences in allometric relationships were found among habitat groups in frogs and between morphs in salamanders.
• The models provide reliable body mass estimates for diverse amphibian species.

Conclusions:

• The new allometric models enable accurate and comparable body mass estimations for amphibians using SVL.
• These estimates facilitate testing of ecological and evolutionary theories directly related to body mass across multiple taxa.
• The findings highlight the importance of considering habitat and morphotype when estimating body mass from length measurements.