Definition of the Caribbean Islands biogeographic region, with checklist and recommendations for standardized common names of amphibians and reptiles

To facilitate biological study we define “Caribbean Islands” as a biogeographic region that includes the Antilles, the Bahamas, and islands bordering Central and South America separated from mainland areas by at least 20 meters of water depth. The advantages of this definition are that it captures nearly all islands with endemic species and with at least some Antillean-derived species, and still circumscribes a region of high biodiversity and biogeographic significance. We argue that Caribbean islands, in this expanded sense, are also cohesive from a conservation standpoint in that they share high human population densities and similar conservation threats. A disadvantage of this definition, strictly applied, is that it includes some islands (e.g., Trinidad) that have mostly mainland species. However, we propose that researchers can increase the stringency of the definition so that it is less inclusive, and make comparisons between different definitions as needed. We provide an updated checklist with standardized common English names for the 1,013 species of amphibians and reptiles occurring in the region, along with principles for constructing common names.