Sprecher
Beschreibung
The western Amazon was extensively influenced by marine incursions. This is evident from the fossil record, which includes mangrove pollen, dinoflagellate cysts and microforaminiferal organic linings. Rhizophoraceae were common, but also Florschuetzia-type pollen were observed in cored sediments from westernmost Brazil. Here we investigate whether sonneratioid mangroves of Southeast (SE) Asian origin extended into the Amazon. To do this, we revisited the Brazilian core 1AS-4a-AM and applied light and scanning electron microscopy (LM and SEM) to selected sporomorphs. We also revised the temporal range of Florschuetzia occurrences and reassessed the morphological description of Florschuetzia impostora by applying confocal microscopy. Based on this study, we amend and extend the description of F. impostora (D’Apolito et al. 2021) and present a new species: Florschuetzia amazonica sp. nov.. Both species strongly resemble F. trilobata and F. ovalis, described from SE Asia, but their specific morphological traits, disjunct distribution and short-spanned abundant occurrences differentiate them. In the Amazon, Florschuetzia mangroves were associated with a high abundance of palms and mangrove-associated ferns, suggesting it occurred in the back-mangrove zone, landward of the Rhizophoraceae belt. We conclude that Early Miocene (or older) dispersal events from South East Asia contributed to a richer and more complex mangrove ecosystem in northern South America than is seen today.