Recent shallow water foraminifera from the Selvagens Islands (Northeast Atlantic) – Assemblage composition and biogeographic significance

Abstract

We report the first survey of shallow-water foraminifera from the Selvagens Islands, an isolated archipelago located in the subtropical Northeast Atlantic. In our samples, we identified 63 species of foraminifera belonging to 43 genera in the >63 μm fraction, including eight species of symbiont-bearing Larger Benthic Foraminifera (LBFs). The assemblages consist mostly of epiphytic species and species associated with coarse grain and hard substrate habitats. Analysis of dead assemblages revealed two main clusters that mostly correspond with the two island groups within the archipelago and relates to their environmental characteristics. Our results provide illustrated baseline information for this remote and relatively pristine habitat, wherein foraminifer community assemblages show a higher degree of similarity to those of the Canary Islands, Cape Verde, and Bermuda as compared to those of Mauritania, Northwest Africa. Hence, this study suggests that geographic proximity and oceanic barriers plays a lesser role than environmental parameters when determining foraminiferal biogeography. In addition, given that all LBF species reported in Selvagens are also present across the Atlantic Ocean, our results suggest that the previously defined ‘Caribbean’ LBF realm should be extended to the subtropical North Atlantic, taking into account local conditions, particularly minimal temperatures, controlling specific LBF assemblages.