Determining the spatial extent of species distributions is a complex challenge; however, this knowledge can provide valuable insights and form the basis for studies focusing on species ecology, evolution, and conservation. Neotropical primates inhabit some of the most diverse and remote forest regions in South and Central America, leading to a deficiency of monitoring efforts. Given the limited data currently available, the spatial distribution of Neotropical primates is currently determined by river boundaries; nevertheless, more focused efforts to understand species distributions on a finer scale are essential. Here, we present the most up-to-date dataset (NeoPrimOD) of Neotropical primate spatial distribution based on recent taxonomic assessments of species. The dataset comprises a curated collection of 28,079 accurate occurrence records and updated distribution maps of the 171 species' potential distributions, based on physical boundaries and occurrence records. This dataset is expected to serve as a key resource for future research related to the distributions of Neotropical primates and can assist in the planning of policies, conservation, and research concerning Neotropical primates.

Scientific efforts to classify the natural world date back to Aristotle, yet taxonomy remains a significant challenge for modern biologists. Various species concepts have fluctuated in favour, most notably the biological, morphological, and phylogenetic species concepts. Recently, the widespread adoption of the phylogenetic species concept has led to extensive taxonomic revisions within Neotropical primates; however, many primatologists argue this has resulted in taxonomic inflation, or an excessive number of recognized species. This study explores the utility of the "ecological speciation" concept by identifying species groupings based on environmental data and occurrence records. We applied four distinct algorithms: hierarchical clustering (HC), k-means clustering (KM), partition around medoids (PAM), and Gaussian Mixture Models (GMM). Our results demonstrate that ecological data can effectively complement traditional classification methods to assess relationships between populations. 

Species distribution maps are essential tools for understanding species ecology, evolution, biogeography, and conservation. However, for many species, particularly those in tropical regions, distribution data often rely on arbitrary estimates due to the logistical challenges of collecting detailed occurrence data. In the case of Neotropical primates, current distribution estimates are based on known occurrences and river boundaries. These approaches, however, fail to account for habitat specificity. Taxonomic uncertainty further complicates distribution estimates, as recent revisions have altered the classification of numerous Neotropical primate taxa. To address these limitations, we developed species distribution models (SDMs) using climatic variables, followed by spatial intersection with forest cover across the Neotropics to assess habitat suitability.

A species distribution is not fixed in space and time; it is shaped and driven by a complex relationship between ecological, evolutionary, and environmental factors. The transformation of habitats, resulting from natural events, anthropogenic activities, and climate shifts, can reshape species distributions by forcing them to disperse, adapt, or perish. If there is connectivity between suitable areas, populations may move through these areas and establish ranges in new areas when previously suitable areas are lost.  If connectivity is not present, species may adapt to changing conditions if given the time through the increased presence of traits that enhance individual survival. If species cannot adapt or move out of unsuitable areas, then reduced gene flow between populations and an increased vulnerability to physiological stress may result in population collapse and, in worst-case scenarios, extinction. 

The rate of deforestation in tropical forests across the Neotropical realm continues to rise. Combined with the effects of climate change, this is reducing the available habitat for forest‑dependent species, including Neotropical primates. In this study, we use species distribution model projections to evaluate temporal changes in habitat suitability for Neotropical primates and to identify priority areas for protected area expansion.

Bioregionalisation is the process of classifying biodiversity into geographically defined communities known as bioregions. In the Neotropics, currently recognised bioregions have been proposed using a variety of taxa and methodological approaches. For Neotropical primates, however, recent advances in species distribution knowledge and taxonomic revisions have substantially changed our understanding of where species occur, rendering earlier bioregional frameworks outdated. In this study, species distribution model outputs were used to re‑evaluate bioregions for Neotropical primates based on habitat suitability, suggested area of occupancy maps, and updated range maps. The resulting bioregions were then examined to assess their robustness and to identify the origin point of Neotropical Primate diversity.