Biogeographic regionalization of Odonata (Insecta) in the Neotropics: contrasting Anisoptera and Zygoptera spatial patterns

The Neotropical region stands as a significant hotspot for Odonata diversity, yet comprehensive spatial patterns have remained less elucidated. This study aimed to provide a comprehensive biogeographical regionalization of the order Odonata across the region, specifically investigating whether its extant suborders exhibit congruent or divergent spatial patterns. Geographic distribution data for 1,533 Neotropical Odonata species (666 Anisoptera, 867 Zygoptera) were sourced from the IUCN and analyzed using the Infomap Bioregion application to delineate distinct bioregions. Spatial associations between Odonata, Anisoptera, and Zygoptera bioregions, and nine thematic regionalizations, including ecoregions, biomes, climate types, and hydrobasins, were quantified using the V-measure (global association) and relative inhomogeneity (local association). The analyses successfully delineated 13 distinct bioregions for the entire order Odonata, 14 for Anisoptera, and 19 for Zygoptera, all supported by high levels of endemism. A moderate yet differentiated spatial association was observed between Odonata bioregions and those of its suborders, with Anisoptera showing a stronger congruence than Zygoptera, indicating Zygoptera’s more fragmented and less overarching biogeographical structure. Hydrological units, particularly watersheds at levels 2 and 3, consistently emerged as the most strongly correlated of odonate bioregions, reinforcing the paramount importance of aquatic habitats for these obligate aquatic organisms. In contrast, climate-based regionalizations showed the weakest spatial association. Local inhomogeneity maps further highlighted regional convergences, with areas like the Amazon basin showing strong Anisoptera congruence, while Zygoptera displayed more fragmented patterns tied to hydrological features across Central and northern South America. These findings strongly suggest that distinct dispersal capabilities of Anisoptera and Zygoptera influenced macro-scale biogeographical patterns, with riverine systems acting as fundamental structuring elements. Here we delineated distinct Neotropical bioregions for Odonata and their suborders, revealing pronounced spatial heterogeneity and endemism across Central America, the northern Andes, the Amazon basin, and the southern Atlantic Forest. We demonstrated that the two suborders possess contrasting architectures: Anisoptera align closely with the overall Odonata regionalization, whereas Zygoptera exhibit a distinct, finer‑grained fragmentation. Watershed‑based partitions (levels 2 and 3) provided the strongest spatial association with odonate bioregions, identifying hydrology rather than climate as the dominant correlate regionalization. Our results establish a theory‑informed baseline for freshwater conservation, linking suborder‑specific dispersal traits with hydrography to guide spatially explicit planning in the Neotropics.