Alternate Title

The Molluscan Fauna of the Florida Middle Grounds with Comments on its Zoogeographical Affinities


Recent studies have indicated that the Gulf of Mexico is bounded by a discontinual series of hard substrates which support faunal and floral assemblages of both temperate and tropical origins. This substrate distribution has had a significant impact on molluscan fauna in the Gulf of Mexico. An investigation of the molluscan fauna of the Florida Middle Grounds has produced 75 species associated with this high relief substrate which is also characterized by hermatypic corals. Although the molluscan fauna is comprised of forms which are predominantly "Caribbean eurythermic" and "Caribbean Restricted" (76%) which is similar in composition to the West Flower Garden Bank of Texas, their species composition is quite dissimilar (only 23% similarity). For these and other reasons, it is proposed that the zoogeographic status of the Gulf of Mexico should be seriously reconsidered by specialists in other faunal groups.