REDUCING THE LATITUDINAL BIAS IN NEOGENE MARINE PALYNOLOGY: INVESTIGATING THE NEOTROPICAL FOSSIL RECORD

Marine palynomorphs such as dinoflagellate cysts (dinocysts) and acritarchs have been widely used for chronology and paleoenvironmental reconstructions in temperate latitude neritic sequences for several decades. Although marine palynology has been crucial in better understanding Neogene stratigraphy and paleoceanography, mostly in the Northern Hemisphere, the limited number of studies in tropical latitudes has led to a biased understanding of the Neogene palynological record. This study presents novel data on dinocysts and acritarchs from the northern Neotropics (Caribbean Sea) as a first step to decrease the latitudinal sampling bias. Analysis of 40 samples spanning the early Miocene (Aquitanian-Burdigalian) reveals distinct biostratigraphic ranges for Achomosphaera alcicornu and Trinovantedinium ferugnomatum, highlighting the need to calibrate dinocyst and acritarch bioevents in the region. In addition, the occurrence of several undescribed species, some of which probably represent key biostratigraphic markers (e.g., Cristadinium sp. of De Verteuil & Norris 1992, Quadrina “incerta”), requires detailed taxonomical classification. Although changes in dinocyst assemblages suggest fluctuations in Caribbean paleoproductivity throughout the early Miocene, the extent and driving factors of these changes remain to be determined. Further analyses are needed to better understand the evolution of Neogene marine palynomorphs, as well as their biostratigraphic and paleoceanographic implications.