Patterns of species richness and endemism of freshwater decapods in Colombia

Abstract Colombia’s freshwater ecosystems are recognized as global biodiversity hotspots; however, the spatial distribution of its decapod fauna remains poorly synthesized. We provide the most comprehensive assessment to date of Colombia’s freshwater shrimps and crabs, spanning 38 subregions across all six major natural regions. By synthesizing a 173-year longitudinal dataset (1853–2026) comprising 157 species and 17,731 specimens from 21 international museums and research institutions, our analysis reveals significant regional heterogeneity in biodiversity and establishes a high-resolution baseline for species distribution. We delineate clear patterns of species occurrence and characterize regional endemism. To ensure robust comparisons across areas with varying sampling intensities and environmental characteristics, we employed the Shannon and Simpson indices alongside a geometric index, effectively integrating species richness with distribution data. These findings establish a foundational framework for future biogeographic research and inform targeted conservation strategies for Colombian freshwater decapods.