Gonolobus in the spotlight: History, diversity, and citizen science

Gonolobus (Apocynaceae) is a distinctive genus of climbing plants, distributed from the southern United States to Argentina. This study presents a comprehensive, integrative analysis of the genus, synthesizing its intricate taxonomic history, biogeographic patterns, and the contribution of citizen science to its modern systematics. We compiled and curated a database of 9415 unique records from herbaria, literature, and the iNaturalist platform. Our analysis reveals that Gonolobus has 127 species with a heterogeneous distribution pattern, with richness concentrated in two major centers: the Mexican Transition Zone and the northern Andes. Endemicity Analysis (NDM/VNDM) robustly identified six areas of endemism, four of which are nested within the geologically complex Mexican region, supporting its role as a cradle of diversification driven by multiple evolutionary processes. This study also provides the first quantitative assessment of the impact of citizen science, demonstrating that iNaturalist hosts data for 57 species (45% of the genus), with over 6400 Research Grade observations, exceeding collection records by more than 12%. This platform has been instrumental in proposing new species, documenting previously unknown populations, and refining the distribution of species for which collection data are deficient or biased by collection efforts. By integrating historical, ecological, and digital data, this work establishes a robust framework for understanding Gonolobus . We conclude that the genus diversity is a product of both historical biogeographic processes, such as speciation in Mesoamerican refugia, and contemporary ecological factors. Our findings underscore the need for continued phylogenetic study and the critical value of citizen science as a complementary tool for researching diverse tropical plant genera.