Diversidade taxonômica e distribuição geográfica de anfípodes marinhos da costa brasileira

Abstract

The knowledge of marine species distribution is essential for delineating biogeographical patterns and informing conservation strategies. This study investigated the beta diversity of marine amphipods in Brazilian coastal and oceanic regions down to 200 meters in depth, aiming to identify patterns of species turnover and compositional similarity among different localities. Data from 138 scientific publications and academic works were analyzed, covering 18 geographic regions along the Brazilian coast, including some oceanic islands, and major diversity indices were applied to detect patterns in regional faunal structure. The results revealed the occurrence of 247 species distributed across 39 families. The highest species richness was observed between the states of Bahia and São Paulo, regions historically associated with greater sampling efforts and a strong tradition of taxonomic research on crustaceans. The analyses identified noticeable patterns of differentiation between the Northeastern and Southeastern-Southern marine provinces, consistent with previous biogeographical proposals for the region. Isolated clusters with low faunal overlap were also observed, suggesting the influence of oceanographic barriers. In addition to the large-scale spatial analysis, the study included a taxonomic inventory of amphipods associated with rhodolith beds in three Brazilian oceanic island localities. The survey identified 30 species of Amphipoda, belonging to 15 genera and 10 families, seven of which are new to science and all from the family Maeridae, which showed marked dominance in the samples. The data highlights the need for increased investment in systematic and taxonomic inventories in structurally complex but underexplored habitats, such as rhodolith beds. Furthermore, this study demonstrates the value of amphipods as sensitive indicators for biogeographical and ecological analyses, contributing to the development of more accurate marine regionalization models and the planning of priority areas for conservation.