UPPER PLEISTOCENE PALEONTOLOGICAL RESOURCES OF GUANTANAMO BAY NAVAL STATION (GTMO), CUBA

Preliminary investigations of paleontological resources on the 45 square miles of Guantanamo Bay Naval Station in southeast Cuba were conducted during three one-week fieldtrips in 2007 and 2008. Here, exceptional deposits of the well-preserved upper Pleistocene Jaimanitas Formation were discovered exposed in road cuts, quarries, and rugged shoreline terraces fringing Guantanamo Bay and islands in the bay. The Jaimanitas Formation consists of variable in-place bioherms of coral and massive beds of broken-up coral thickets (storm deposit?). Some large (~2 m high), branching corals appeared to be in place. Mollusks, decapods, and echinoids were found weathering out of spaces in and around the corals, however, not a single vertebrate fossil (e.g., shark tooth), was found. The Jaimanitas Formation varies in hardness depending on coral quantity, matrix type, and case-hardening. At several exposures dark bits of rock (volcaniclastics; e.g., Officers Landing site) are intermixed and at other sites the reef terraces overlie thick bedded conglomerates (e.g., Girl Scout Beach).

A total of seventeen sites were sampled (either surface collected and/or bulk sampled) that combined yielded 48 bivalve, 38 gastropod, and one scaphopod species. Other invertebrate taxa (e.g., corals, decapods, and echinoids) await identification. Most mollusks collected were preserved as complete or nearly complete shells and some still retained their original color. Preliminary ecological analysis, based on living cognates, of the most abundant group of mollusks, the bivalves, indicates that nearly all are shallow-water taxa that inhabited either hard substrates (coral or rock; e.g., Lithophaga spp.), sand substrates [e.g., Periglypta listeri (Gray, 1838)], sea grass beds [e.g., Bractechlamys antillarum (Recluz, 1853)], or can be found attached to seafans [e.g. Dendostrea frons (Linnaeus, 1758)]. All mollusks identified from the 17 sites represent taxa that presently live along Cuba's coast. It is anticipated that additional collecting will increase the number of species considerably given that an estimated 1051 living species (not all with preservable hard parts or shallow-water taxa) have been recognized in Cuban waters.