The monophyly of Microhylidae is supported by an overwhelming accumulation of synapomorphic larval features. Despite the distinctiveness of the microhylid tadpole, few studies have focused on larval development. Microhylid larval morphology is usually described and based on standard tables that imply that developmental events at equivalent stages of overall tadpole development are independent from species-specific patterns of developmental timing. Herein, we present additional developmental data based on external morphology and field data on larval growth for the gastrophrynine microhylidDermatonotus muelleri. We describe internal morphological variation (e.g., skeletal and soft systems) during larval development. The results indicate that the onset of some metamorphic changes occur earlier than those implied in current anuran developmental tables. This study provides baseline information for microhylid species that will allow comparisons of ontogenetic trajectories, heterochronic patterns influencing larval body plan, and the role of larval morphology on the adult microhylid body plan.