Gammaridean Amphipods

Abstract

Although gammaridean amphipods number over 7,900 species worldwide, only 43 marine and estuarine species have previously been reported from Costa Rican waters. The majority of the records is from the Pacific, resulting from J.L. Barnard's work on material collected during the Allan Hancock Pacific Expeditions; a scant handful of records is from the Caribbean coast. In addition, one terrestrial and one freshwater amphipod species have been reported from Costa Rica. Five gammaridean species from Costa Rican waters have not been found elsewhere to date and may prove to be endemic; a sixth possibly endemic species from Isla del Coco has also been reported once (questionably) from the Caribbean coast of Colombia. Recent collecting efforts on both coasts of Costa Rica have resulted in records of at least 20 gammaridean amphipod taxa previously unreported from that country. These records are based upon a preliminary examination of the samples and many more records are anticipated as the remainder of the material is identified. A list of species and literature references, as well as information on distribution, depth range, and habitat type, are presented in tabular form for all gammaridean amphipods known from Costa Rica to date.