Overview

Amphibians are a conspicuous and ecologically important component of the world’s vertebrate fauna, with more than 8,800 species worldwide, more than 1,200 species in Brazil, and an average of 120 new species described per year. They are also a highly endangered group whose current rate of extinction is hundreds or thousands of times greater than the background extinction rate. Our research seeks to discover and describe amphibian diversity and the evolutionary events and processes that explain it. Specifically, we are mainly pursuing three interrelated lines of research.

Our research is generously supported by

Amphibian systematics

The general objective of our research in amphibian systematics is to understand the phylogenetic diversification of amphibians and how it relates to the evolution of particular character systems, including morphological, molecular, and behavioral evolution. Through fieldwork and the examination of museum specimens and tissues, we collect evidence from DNA sequences (including Sanger sequencing, high-throughput sequencing, and museomics) and adult and larval morphology and behavior to study several groups of amphibians, with emphasis on Neotropical clades.

Amphibian chemical defense

Amphibians are characterized by their naked, highly permeable skin that provides meager mechanical protection against the predators, parasites, and pathogens that thrive in the moist environments they inhabit. However, all amphibians are protected by an exocrine defense system composed of cutaneous poison glands—specialized cells that secrete a variety of defensive chemicals, defined as substances that are produced in order to reduce the risk of bodily harm by another organism. These secretions are believed to function as an important component of the innate immune system in defending against pathogens and parasites and are also involved in complex antipredator mechanisms. Our studies focus primarily on the evolution and ecology of chemical defense in poison frogs of the families Bufonidae (Melanophryniscus) and Dendrobatidae (independently derived in Epipedobates, Ameerega, and Dendrobatinae), which do not biosynthesize their chemical defenses but instead sequester lipophilic alkaloids from their diet (primarily from mites and ants). More recently, we have added studies of Brachycephalus, which is chemically defended by tetrodotoxin.

Amphibian Ecology and Conservation

Studying the ecology of amphibians is essential both to understand their evolutionary history and ensure their survival. From the movement ecology and diel activity of Melanophryniscus to the invasion biology of the the American bullfrog, Aquarana catesbeiana, in the Atlantic Forest and long-term passive acoustic monitoring in the Serra do Mar at the Estação Biológica de Boracéia (Boracéia Biological Station), our research employs comparative and experimental approaches to increase understanding of the ecological relationships and processes of amphibian communities.