Checklist, assemblage composition, and biogeographic assessment of Recent benthic foraminifera (Protista, Rhizaria) from São Vincente, Cape Verdes

Abstract

We describe for the first time subtropical intertidal foraminiferal assemblages from beach sands on São Vincente, Cape Verdes. Sixty-five benthic foraminiferal species were recognised, representing 47 genera, 31 families, and 8 superfamilies. Endemic species were not recognised. The new checklist largely extends an earlier record of nine benthic foraminiferal species from fossil carbonate sands on the island. Bolivina striatula, Rosalina vilardeboana and Millettiana milletti dominated the living (rose Bengal stained) fauna, while Elphidium crispum, Amphistegina gibbosa, Quinqueloculina seminulum, Ammonia tepida, Triloculina rotunda and Glabratella patelliformis dominated the dead assemblages. The living fauna lacks species typical for coarse-grained substrates. Instead, there were species that had a planktonic stage in their life cycle. The living fauna therefore received a substantial contribution of floating species and propagules that may have endured a long transport by surface ocean currents. The dead assemblages largely differed from the living fauna and contained redeposited tests deriving from a rhodolith-mollusc carbonate facies at <20 m water depth. A comparison of the Recent foraminiferal inventory with other areas identified the Caribbean and Mediterranean as the most likely source regions. They have also been constrained as origin points for littoral to subtidal macroorganisms on other Cape Verdean islands. Micro-and macrofaunal evidences assigned the Cape Verde Current and North Equatorial Current as the main trajectories for faunal immigrations. The contribution from the NW African coast was rather low, a pattern that cannot be explained by the currently available information.