PALEOECOLOGICAL EVIDENCE OF RAPHIA IN THE PRE-COLUMBIAN NEOTROPICS

Disjunctions between Africa and the Neotropics present a puzzle that i s key to understanding the biogeography of the diverse floras and faun as of both continents. Many authors have proposed that Raphia taediger a Maur., the sole Neotropical representative of an otherwise African g enus, has been introduced to the New World. Paleoecological data from a freshwater swamp in Nicaragua, which yielded R. taedigera pollen dat ing to 2800 +/- 90 y before present (BP) and Raphia seed fragments fro m 2040 +/- 60 BP are presented. These illustrate that Raphia taedigera arrived in the New World before trans-Atlantic trade by humans and th us arrived as a result of a natural phenomenon. The lack of differenti ation of R. taedigera from the African sister taxon, R. vinifera, sugg ests recent separation of the two species (i.e. after the creation of the southern Atlantic Ocean by the splitting of West Gondwana). Other evidence supports dispersal of Raphia by ocean currents. The palm prob ably arrived from Africa by floating as an individual fruit or on a ra ft of vegetation. Thus, R. taedigera represents another example of tra ns-Atlantic dispersal, strengthening the link between the flora and fa una of Africa and the Neotropics.