Fossil crabs in the Caribbean: taphonomic comparisons as an informed indicator of underexploited occurrences

Abstract

The Antilles include over 100 islands, each with a rock record that embraces different slices of the stratigraphic succession; this is probably the most beguiling geological quality of the region. Both authors have been collecting fossil crabs (decapod crustaceans) from these islands for almost 30 years. Experience has demonstrated that, whatever fossil crustaceans have been described from an island, there are undoubtedly more waiting for attention. Marine decapods can commonly be collected in hand specimen. If there are poorly lithified sedimentary rocks, they will likely repay sieving with an abundance of fragments. For many stratigraphic horizons it is only the disarticulated elements such as these that are known, but they are identifiable and can be diverse. We promote three units from the Antilles as being highly likely to produce new and well-preserved faunas of decapod crustaceans: the Yellow Limestone Group (Eocene, Jamaica); the Anguilla Formation (Miocene, Anguilla); and the Rockly Bay Formation (Pliocene, Tobago). Both the Yellow Limestone Group and Anguilla Formation have produced fossil decapods, albeit indifferently preserved. In contrast, both units have yielded a diversity of well-preserved echinoids; the reasons for this contrast remain speculative. The Rockly Bay Formation is the most barnacle-rich unit in the Antilles, yet decapods, another marine arthropod group with a calcareous skeleton, remain undescribed, but are present. These units need to be exploited for fossil decapods and, in so doing, these new data will improve the known palaeobiodiversity of the Antillean region.