The origin and distribution of shallow water gammaridean amphipoda in the Gulf of Mexico and Caribbean Sea with notes on their ecology

Vita.The present study details the occurrence, distribution and origins of shallow water marine gammarideans in the Gulf of Mexico and Caribbean Sea. One hundred and forty species are diagnosed or discussed and keys to the families, genera and species are provided to further distinguish them. Twenty three new species are described and fully illustrated. They include species of the following genera: Amphilochus (2 species), Ampithoe, Atylus, Ceradocus, Corophium, Eriopisa, Eusiroides, Gammaropsis, Gitanopsis, Liljeborgia, Listriella (3 species), Maera, Megaluropus, Netamelita, Parametopella, Photis (2 species), Platyischnopus, Polycheria, and Seba. One emphasis of study was the ecological grouping of epiphytic amphipods generally associated with either of two series of habitats (biotopes): 1) general soft bottom areas dominated by the physical substrate, or 2) special habitats dominated by a complex biological community on hard substrate or a biological substrate. The first series included: bays, lagoons, intertidal zones, and subtidal areas. The second series included: coral, serpulid and oyster reefs, tropical and temperate grass flats, submerged offshore banks, and offshore artificial substrates. Amphipods found in these habitats are listed and discussed. Dispersal and colonization mechanisms of the amphipods in these habitats are also discussed. Rafting was found to be the chief means of dispersal between these habitats. Colonization followed a predictable pattern based on substrate utilization and composition.