Two more sibling species of alpheid shrimps associated with the Caribbean Sea anemones Bartholomea annulata and Heteractis lucida

We have described two new species of snapping shrimp, Alpheus polystictus and A. roquensis. The new species form part of a complex of four sibling species associated with Caribbean sea anemones, the others being the well-known A. armatus Rathbun, 1900 and the recently described A. immaculatus Knowlton and Keller, 1983. Alpheus roquensis is found with the anemone Heteractis lucida, while the other three shrimps live with Bartholomea annulata. In laboratory choice experiments, each shrimp species prefers the species of an emone with which it is typically found in the field, although each can shelter under the other species of anemone. All four species are extremely similar morphologically, being distinguished largely on the basis of color pattern. The validity of the species is confirmed by the total absence of interbreeding; heterospecific male-female pairs are never found in the field, and it is impossible to force pairings between species in the laboratory. Alpheus polystictus is rare in Jamaica and Haiti, while in Venezuela it is sometimes the dominant species to depths of 10 m. In the areas examined, it has always occurred with at least one of the other two Bartholomea associates. The geographic distribution of A. roquensis is more limited, as there are no reports of alpheids associated with Heteractis lucida, and none has been found with this anemone in Jamaica.