Ontogenetic body form changes in three ecological morphotypes of anuran tadpoles

Metamorphic vertebrate species are of particular interest in ecological and evolutionary studies because the decoupling of larval and adult growth patterns potentially allows adaptive diversifications of the separate stages. Larval and adult growth might be much more constrained if allometric patterns were constant throughout ontogeny. To better understand how differential growth patterns might contribute to tadpole diversification, we have analyzed growth allometries in relation to interspecific morphometric differences in Gastrophryne carolinensis, Acris gryllus, and Hyla gratiosa. Growth patterns in all species are significantly allometric and moderately concordant, despite many differences in detail. The species can be completely discriminated in even the smallest post-hatching tadpoles. However, the differences that distinguish the species do not seem to be a function of differential growth patterns at the tadpole stage. Rather, morphological differences ostensibly originate during embryonic development and are well established by the time the tadpoles become free-swimming.