Amphibians and Reptiles Exhibit Different Ecological and Evolutionary Spatial Patterns in the Amazon Basin

Understanding spatial variability in ecological and evolutionary patterns is key to Amazonian biodiversity conservation. This study examined taxonomic, phylogenetic, and functional diversity across amphibians and reptiles, assessing the influence of elevation, interrelationships among metrics, and distribution across five Amazon Basin ecoregions, exploring the "cradle" (speciation) and "museum" (lineage preservation) hypotheses. We analyzed 1011 amphibian species from three lineages and 828 reptile species from four lineages. Integrating distribution maps, phylogenies, and trait data, we calculated phylogenetic (PD), functional (FD), and taxonomic (TD) diversity, including mean phylogenetic (PD_mntd) and functional (FD_mntd) distance to the nearest taxon. We examined spatial regressions between diversity metrics and elevation, assessed correlations among metrics, and compared diversity metrics across ecoregions for each lineage. Diversity metrics across amphibian and reptile lineages reveal distinct geographical patterns related to elevation. Anurans exhibit higher PD, FD, and TD in the western Amazon, while squamates show hotspots at low altitudes. Testudines are linked to major rivers, and crocodilians display high PD near the equator. Anurans and squamates show elevated PD_mntd and FD_mntd in the Andes, whereas testudines are found in cratonic regions. Significant correlations and notable differences among ecoregions were found, especially in the Andes and low regions of the Amazon Basin. This study highlights the diverse eco-evolutionary patterns among amphibian and reptile lineages in the Amazon Basin, each exhibiting distinct hotspots distributed across ecoregions. The findings align with the cradle-museum hypothesis, suggesting that some regions serve as centers of ongoing diversification, others preserve ancient lineages, or serve as both. The cradle-museum hypothesis should be carefully analyzed, as each taxon presents a distinct pattern. This research underscores the necessity for targeted conservation strategies tailored to distinct ecological and evolutionary dynamics across ecoregions.