The Tadpoles of the Iron Quadrangle, Southeastern Brazil: A Baseline for Larval Knowledge and Anuran Conservation in a Diverse and Threatened Region

Knowledge of tadpole morphology and natural history is essential to understand and protect anuran diversity. We provide a regional taxonomic catalog of the tadpoles that occur in the Iron Quadrangle (IQ, Quadrilátero Ferrífero), a hotspot of amphibian diversity and highly threatened region in southeastern Brazil. Using a standardized methodology, free-living larvae of 67 species belonging to 25 genera and 11 families are described and illustrated, including photographs of most species in life, natural history notes, and taxonomic comments. Larvae of seven species and/or candidate species (viz., Fritziana aff. fissilis, Bokermannohyla gr. circumdata, Bokermannohyla aff. nanuzae, Pithecopus aff. rohdei, Scinax aff. machadoi, Scinax aff. perereca, and Scinax rogerioi) are described for the first time and compared to congeners. Most tadpoles of candidate species exhibited remarkable differences in morphology compared to closely related congeners, which could provide diagnostic characters for further formal descriptions. The observed material of many of the previously known tadpoles deviated from published descriptions, which might be useful in future taxonomic studies (e.g., providing characters for the taxonomic delimitation of either small-range species or widespread cryptic species complexes). Illustrated dichotomous and multi-Access identification keys are presented, allowing most species to be readily identified using reliable characters. Considering the high-level threat and huge impacts on IQ's biodiversity and ecosystem services, particularly from mining, the results presented here provide an important foundation for research and conservation of anuran in this region. Finally, we stress that IQ harbors one of the most ecomorphologically diverse Brazilian tadpole assemblages.