The Heterobranchia gastropods from the Cabo Verde Islands (NE Atlantic): A hot-spot of endemism

The Archipelago of Cabo Verde is located in the northeastern Atlantic Ocean, off the coast of Senegal in West Africa. According to recent studies, it constitutes a distinct biogeographical subprovince with a subtropical affinity. The archipelago is well known for its high levels of marine endemism, likely due to the geological age and the isolation of the islands maintained by ocean currents and upwelling systems. In this paper, taxonomic findings from a field survey conducted on the islands of Sal, Boa Vista, and São Vicente are presented, accompanied by detailed geographical and ecological data to enhance the documentation of the distribution and habitat of species in the archipelago. Specimens were collected from tidal rock pools and subtidal zones down to 18 m depth through snorkeling and SCUBA diving. Sampling methods included direct hand collection, surface brushing, and gathering algae into sealed plastic bags for later examination. In the laboratory, specimens were sorted into morphospecies, photographed, cataloged, and preserved in 99 % ethanol following relaxation. A total of 27 species of Heterobranchia were identified, including one new record for the archipelago (Caloria quatrefagesi) and one species likely new to science (here identified as Facelinidae sp.). Notably, 44 % of the species collected are endemic to Cabo Verde, further highlighting the unique marine biodiversity of the region.