EVOLUTIONARY DIVERSITY AMONG ATLANTIC COAST MANGROVES

Current knowledge of intraspecific variation of mangrove species is li mited in terms of rangewide distributions and is mostly restricted to morphological analyses, which have indicated a high degree of homogene ity. However, our analyses of the aliphatic hydrocarbon and triterpeno id fraction of foliar waxes (by gas chromatography and mass spectrosco py) of mangrove species (Rhizophora mangle, Avicennia germinans and La guncularia racemosa) from Gabon in West Africa and French Guiana in So uth America show significant genetic differentiation between eastern a nd western Atlantic provenances. The greater diversity in lipid compos ition, and the tendency for longer carbon chain lengths in all taxa fr om Africa, may suggest that American mangroves exhibit derived charact eristics. A consequence of this hypothesis would be that Atlantic mang roves are unlikely to have dispersed from the Tethys via the Pacific, as has been proposed by some authors. More widespread sampling within the Atlantic and east Pacific region is needed to support and confirm these results. (C) Elsevier, Paris.