Primates in the Endangered Araucaria Pine Forest of the Largest City of Southern Brazil: A Current Overview

Background and Research Aims: The Araucaria Pine Forest (APF) is the most threatened Atlantic Forest phytophysiognomy, with 4% of its original area remaining. In Paraná, Brazil, it faces the worst conservation status. Primates play key ecological roles in this ecosystem, yet their distribution in the Metropolitan Region of Curitiba (MRC) remains poorly documented, and studies shows a historical bias toward brown howler monkeys ( Alouatta guariba ). This study provides an updated, spatially explicit overview of free-ranging native and exotic primates in the MRC, focusing on APF remnants. Methods: We compiled primate occurrence records from 2000 to 2025 using scientific literature, museum collections, environmental and health databases, citizen science platforms, and personal observations. Coordinates were verified via Google Earth, and spatial analyses were done in QGIS. A 1,000-meter grid and Kernel Density Estimation identified distribution patterns and hotspots. Results: We recorded 604 primate occurrences across five species. Three natives: brown howler monkeys, southern black-horned capuchin monkeys ( Sapajus cucullatus ), and southern muriquis ( Brachyteles arachnoides ). Two exotics: black-tufted marmosets ( Callithrix penicillata ) and common marmosets ( Callithrix jacchus ). Three key patterns were revealed: exotic marmosets were concentrated in Curitiba’s northern urban area; brown howler monkeys dominated southern Curitiba and the southern MRC; and capuchin monkeys clustered near the Serra do Mar . Records grew steadily: few before 2010, moderate during the 2010s, and a sharp rise after 2014 with SISS-Geo and iNaturalist’s popularity. Conclusion: Primate distribution in the MRC shows spatial segregation between native and exotic species. Brown howler monkeys remain relatively common despite yellow fever outbreaks, while capuchin monkeys and muriquis appear rare or absent from smaller APF fragments. Implications for Conservation: Urgent actions include protecting and restoring APF remnants, controlling exotic marmosets, and targeted surveys for rare natives. Continuous monitoring integrating citizen science and health databases is crucial for conservation in this urban-forest mosaic.