The phylogeny of the Cocoeae (Arecaceae) with emphasis on Cocos nucifera

Abstract

The tribe Cocoeae contains economically important palms including Cocos nucifera, Elaeis guineensis, Attalea speciosa, and Bactris gasipaes. This study, based on the nuclear prk gene sequence, addresses the monophyly of the subtribes of Cocoeae, the closest relatives of Cocos nucifera, and biogeographical implications of its distribution. The Cocoeae are divided into the spiny and non-spiny taxa. Molecular data alone suggest that Cocos nucifera did not originate in the western Pacific; it may be the only extant member of its lineage. Several Cocoeae fossils from New Zealand and India were used as calibration points to estimate times of divergence of clades. A hypothesis for the origin of the Cocos clade based on the phylogeny was postulated. It is hypothesized that Cocoeae originated from South America, diversified and radiated eastward toward Africa, Madagascar, and India, and southward to Australia and New Zealand via the Antarctic corridor. The estimated divergence dates were corroborated with major tectonic events.