Morphological and Molecular Variation in the Pumpkin Toadlet, Brachycephalus ephippium (Anura: Brachycephalidae)

Abstract A recent study demonstrated marked variation in cranial shape between a population of Brachycephalus ephippium from Jundiai in Sao Paulo state and populations from Atibaia and Sao Francisco Xavier (Sao Paulo) and Macae de Cima in the state of Rio de Janeiro in southeastern Brazil. This result contrasts with earlier work describing differences in cranial shape between the population from Rio de Janeiro and those from Sao Paulo. Here, we investigate the nature and extent of variation between populations of B. ephippium using two lines of evidence. First, we reevaluate patterns of morphological variation by incorporating semi-landmarks into the quantitative description of cranial shape and by using scanning electron microscopy (SEM) to describe qualitative skeletal features. Second, we assess molecular variation in the mitochondrial genes cytochrome b, 12S rRNA, and 16S rRNA, and the nuclear Rag-1 gene, totaling 3,697 base pairs. Geometric analyses of cranial shape and SEM images of skeletal traits ...