MEPS prepress abstract   -  DOI: https://doi.org/10.3354/meps14407

ABSTRACT: The biogeography of hydrozoans represents a broad scope of study that involves various challenges due to their diverse distributional strategies and life cycle characteristics. This work aims to study the biogeographic patterns of hydrozoans in the Gulf of Mexico. Occurrence records on hydrozoans were compiled through the Global Biodiversity Facility Information database and peer-reviewed literature. Biogeographic patterns were addressed through the identification of biological assemblages with a Hierarchical Cluster with Contiguity Constraint; the decomposition of beta diversity into species replacement, nestedness, and Local Contribution to Beta Diversity (LCBD); and the identification of areas of endemism with a Parsimony Analysis of Endemicity (PAE). The northern Gulf of Mexico and the Yucatán peninsula encompass a large assemblage that splits into smaller ones at different levels, characterized by species replacement and high LCBD values. In contrast, the southern Gulf of Mexico encompasses a homogenous assemblage, which shows low LCBD values and highly contributes to nestedness. PAE identified 19 areas of endemism of higher level conformed by 30 grids, concentrated mainly in shelf zones of the Yucatán and Florida peninsulas. The distribution patterns of hydrozoans in the Gulf of Mexico may be shaped by the life cycle characteristics of the taxa and the geological history of the region, relating either to neritic or oceanic zones. The northern Gulf reflects a heterogeneous biological composition with a complex biogeographical history, which makes this area of particular interest for future studies since it likely represents a transition zone, yet this must be corroborated in the future.