Exploring environmental and biogeographic patterns of Ceriantharia (Cnidaria) across the Atlantic through habitat suitability modeling

Abstract Tube-dwelling anemones of the subclass Ceriantharia are important components of benthic ecosystems, contributing to habitat complexity and supporting diverse biological interactions. Despite their ecological relevance, most species remain poorly studied due to sampling difficulties and the limited knowledge available regarding their ecology, biogeography, and dispersal. In this context, habitat suitability modeling provides a valuable framework for identifying environmentally suitable areas for understudied marine taxa. Here, we present the first broad-scale habitat suitability assessment for nine Atlantic Ceriantharia species using MaxEnt models. Model projections were interpreted as environmentally suitable areas sharing conditions with known occurrences rather than as estimates of realized or potential geographic distributions. All models showed satisfactory predictive performance (AUC ≥ 0.70; TSS ≥ 0.40). Bathymetry emerged as the dominant environmental predictor, followed by temperature and slope, indicating that broad-scale oceanographic gradients strongly influence habitat suitability. Three major centers of environmental suitability were consistently identified across the Atlantic basin, encompassing the western Atlantic, the eastern Atlantic, and high-latitude regions. Although several models recovered suitability patterns consistent with documented occurrences, others projected environmentally suitable areas beyond currently known records, highlighting the influence of limited knowledge regarding species dispersal, population connectivity, and historical biogeography. These results provide the first comprehensive overview of habitat suitability patterns for Atlantic Ceriantharia, identify priority regions for future sampling, and demonstrate the importance of integrating ecological, oceanographic, and life-history information to improve habitat suitability assessments for poorly known benthic marine invertebrates.