LATE TERTIARY MICROFOSSIL FLORA FROM THE REPUBLIC OF HAITI

Abstract

Twenty‐five fossil pollen and spore types have been recovered from the late Miocene to possibly middle Pliocene Artibonite flora of Haiti. These include monolete fern spore (36%), Alsophila (6%), Pteris types 1–3 (type 1 = 11%), cf. Antrophyum, trilete fern spore (types 1, 2), Pinus (16%), Palmae (types 1, 2), Hygrophila, Chenopodiaceae/Amaranthaceae, Compositae (types 1–4; 9%), Alchornea, Alfaroa/Oreomunnea, Oryctanthus, Malpighiaceae, Allophylus, and unknown types 1–3. The principal vegetation types suggested by the fossil flora are pine forest and cloud forest, with a fern marsh bordering the depositional basin. Communities of drier to arid aspect, savannas, and high altitude vegetation are not represented. Annual temperatures ranged between about 23 and 26 C at 400 m elevation, and 17 and 19 C at elevations of about 1,400 m. Annual rainfall is estimated at about 1,300 mm and was seasonal. The affinity of the flora is distinctly North American, consistent with plate tectonic models showing the proto‐Greater Antilles located off southwestern Mexico during the early Tertiary. The development of South American affinities, other than by long‐distance dispersal throughout the Cenozoic, was facilitated in later Tertiary times by eastward movement away from Mexico/proto‐Central America and by emergence of the Lesser Antilles in the Eo‐Oligocene.