A New Sponge Associated Shrimp of the Genus Periclimenaeus Borradaile, 1915 (Decapoda, Palaemonidae) from the Tropical Eastern Atlantic, Cabo Verde Islands.

A new species of the caridean shrimp genus Periclimenaeus is described from the Cabo Verde Islands, tropical eastern Atlantic. Periclimenaeus ramili sp. nov. is morphologically most similar to the north-eastern Atlantic P. aurae dos Santos, Calado & Araújo, 2008, the western Atlantic P. pearsei (Schmitt, 1932), and particularly the eastern Pacific P. hancocki Holthuis, 1951, all sharing many features, especially the reduced incisor process of the mandible, the general shape of the second pair of chelipeds and ambulatory pereiopods, and the telson armament. Based on these features, a new species group is established here to include these four species. Periclimenaeus ramili sp. nov. can be readily distinguished from P. aurae and P. pearsei by the shape of the dactylus of the first pereiopod chela. From P. hancocki, the new species can be distinguished, among other features, by the shorter rostrum armed with lower number of dorsal teeth, the relative length of the scaphocerite to the antennular peduncle, and by the slender distal articles of the third maxilliped. The new species is also reported to excavate its own burrows for living inside its sponge host, a behaviour previously unknown in species of the genus.