Andrade, F. S. de, M. L. Lyra, D. Baêta & L. F. Toledo

Unveiling cryptic diversity in the genus Arcovomer (Anura: Microhylidae): description of two new species from the Brazilian Atlantic Forest. pp. 77-96 plus Supplementary material.

Abstract. The Brazilian Atlantic Forest is one of the world’s most threatened biodiversity hotspots, harbouring high levels of species richness and endemism, including more than 700 amphibian species. Although considerable progress has been made in describing this diversity, new species continue to be formally recognized each year, and many lineages remain poorly studied. Here, we use an integrative approach combining molecular, morphometric, and bioacoustic data to reassess species diversity within the frog genus Arcovomer (Anura, Microhylidae), long regarded as monotypic. Our results reveal the presence of three deeply divergent lineages within the genus Arcovomer. One corresponds to A. passarellii, the type species from the state of Rio de Janeiro, while the other two represent distinct lineages from the states of Espírito Santo and São Paulo, respectively. Phylogenetic analyses based on mitochondrial and nuclear markers recovered Arcovomer as a strongly supported clade, and morphometric and acoustic evidence combined with molecular data support the distinctiveness of these lineages, leading to the description of two new species. These species are geographically structured across distinct ecoregions of the Brazilian Atlantic Forest, highlighting the conservation relevance of recognizing independently evolving, range-restricted taxa. By revealing previously overlooked diversity within this genus, this study highlights the importance of integrative taxonomy, long-term specimen curation, and sound archives for documenting and conserving biodiversity within one of the world’s most threatened biomes.

Key words. Amphibia, genetic divergence, bioacoustics, endemism, integrative taxonomy, biological collections.