Phytoliths from the coastal savannas of French Guiana

Phytolith reference collections are a fundamental prerequisite for accurate interpretation of fossil phytolith assemblages used in reconstructing vegetation histories. As part of a multi-disciplinary research project studying Late Holocene landscape transformations associated with pre-Columbian raised field complexes in the coastal savannas of French Guiana, phytolith production in selected plant species with high environmental and economic significance native to the region was examined. A total of 49 families, 92 genera, and 108 species were analysed. Phytolith abundance in each specimen was rated qualitatively and morphotypes described following modern standards of nomenclature. Of the 92 non-Poaceae species tested, 37 contributed phytoliths that are diagnostic to at least the family level. Two of these are newly-discovered phytolith morphotypes isolated from Protium guianense (Burseraceae) and Thelypteris confluens (Thelypteridaceae [Pteridophyta]) which have not been described previously. This work represents the first systematic undertaking to establish a phytolith reference collection of French Guiana flora. Results reinforce the usefulness of phytolith analysis for distinguishing ecologically significant taxa, and therefore major vegetation formations. The creation of a comprehensive reference collection for French Guiana improves taxonomic resolution and has provided the necessary ground work for the interpretation of palaeoevironmental and archaeological records in the region.