ABSTRACT Aim The evolution of montane species provides critical insights into the drivers of adaptation and diversification. Topographic complexity, a defining feature of many mountainous landscapes, promotes ecological and geographic isolation, often accelerating speciation rates. However, the extent to which topographic complexity directly shapes diversification remains unresolved. Here, we investigate the evolutionary dynamics of Anolis lizards across Neotropical mountain ranges to test two hypotheses: (1) higher elevation environments promote higher speciation rates in species that inhabit them; and (2) greater topographic complexity and climatic stability (i.e., lower past climatic‐change velocity) positively influence speciation rates. Location The Americas. Time Period Present. Major Taxa Studied Anolis lizards. Methods We gathered topographic complexity and past climatic‐change velocity data for 303 anole species and performed phylogenetic analyses to assess how speciation rates change across mountain ranges in the Americas. Results We found that topographic complexity and past climatic‐change velocity do not significantly influence speciation rates, diverging from prior studies that link rugged landscapes or past climatic‐change velocity to high diversification rates. Main Conclusions Our findings challenge assumptions about the direct role of topographic complexity in speciation, highlighting the need to consider multifaceted ecological and biogeographical factors driving evolutionary processes. By disentangling the relative contributions of climatic stability (i.e., lower past climatic‐change velocity) and topographic heterogeneity, this study highlights the complex dynamics shaping biodiversity in tropical mountains and calls for further integrative approaches to understand species diversification in the face of climatic and geological change.
Salazar et al. (2026) studied this question.