Unraveling the herpetofauna diversity in canga and forest ecosystems of the Eastern Amazon

Species inventories are essential for discovering new taxa, improving knowledge of species' geographic distributions, characterizing local richness, evaluating biodiversity loss, and contributing to the conservation of endangered areas, including those with endemic and rare species. The southeastern region of Pará, Brazil, encompasses a transitional zone between the Amazon and Cerrado biomes, marked by a mosaic of natural environments with high variability in relief, substrates, and geological attributes. We conducted a comprehensive survey of the region's herpetofauna, combining taxonomic surveys with molecular characterization, with a particular focus on species associated with savanna-like environments known as canga. We selected four sampling sites: one within the Serra dos Carajás mosaic of protected areas and three in the surrounding region, including São Geraldo do Araguaia, Conceição do Araguaia, and Ourilândia do Norte/São Félix do Xingu. Our inventory recorded a total of 242 species (99 amphibians and 143 squamate reptiles), including ten new records for the state of Pará and two notable range extensions. We also generated a DNA barcode reference library of 860 sequences (436 COI and 424 16S rRNA) from 500 specimens. Approximately 58.4% of amphibian species and 32.2% of squamate reptile species were supported by at least one reference barcode. Our dataset includes five novel COI and two novel 16S rRNA records for amphibians, and 25 novel COI and 13 novel 16S rRNA records for squamate reptiles.