Encyclopedia of Islands

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Biogeography of the Greater Antilles

The Greater Antilles includes Cuba, Hispaniola (Haitiand the Dominican Republic), Jamaica, and Puerto Rico (including the Virgin Islands) (Fig. 1). Parts of many of these islands have changed position in the past. For example, the southern part of Hispaniola (“south island”) was separate from the rest of Hispaniola for much of its early history and was located well west of that island. The mountains of eastern Cuba were likely part of northern Hispaniola. It is also likely that parts of eastern Hispaniola were united with Puerto Rico. The Greater Antilles has extensive areas of limestone, and some have been uplifted into high mountain plateaus. Rainfall falling on these karst areas creates crevices, hollowing out sinkholes and even deep caverns. These features provide additional important habitats that further increase biodiversity.

Map of the Antilles showing its biological regions

FIGURE 1. Map of the Antilles showing its biological regions

These sinkholes and caves are also places where fossil and semifossil remains of animals are found. Their presence is one reason that there is such an excellent record of the kinds and ages of vertebrates that lived on the islands.

In the Greater Antilles, many plants and animals are derived from South American ancestors. One hypothesis as to how South American terrestrial vertebrates dispersed to the Greater Antilles is the GAARlandia theory proposed by Ross MacPhee and Manuel Iturralde-Vinent.

They believe that about 35 million years ago proto-Cuba, Hispaniola, and Puerto Rico were connected to north-western mainland South America via the now submerged Aves Ridge, and they give the name GAARlandia (from Greater Antilles + Aves Ridge) to the overall structure.

This bridge of emergent islands would have been above sea level for about 2 million years (between 35 and 33 million years ago). Terrestrial mammals such as sloths, monkeys, and rodents would have been able to make their way to GAARlandia at that time, later dispersing to other islands over water or via vicariance events. Rodents, sloths, monkeys, and even the Antillean piculet (Nesoctites micromegas), a primitive woodpecker, may have dispersed to the central Greater Antilles via this route. Other plants and animals, such as soricomorphs (including the large solenodons and the much smaller island shrews of the genus Nesophontes), most likely originated in North America and were able to disperse to the Greater Antilles via vicariance events when pieces of the proto-Antilles passed close to the southern tip of the North American continent. There is recent evidence for the antiquity and uniqueness of solenodons. Analysis of a sequence of 13,885 base pairs of both nuclear and mitochondrial genes of Solenodon paradoxus indicates that solenodons separated from other placental mammals 76 million years ago. The last connection between the proto-Antilles and mainland North America was severed 70–80 million years ago, and it is likely that solenodons became part of the Antillean fauna by vicariance at that time.