The Amazon drainage basin is extremely biodiverse, yet the origins of this diversification remain much debated. One of the possible drivers of plant diversity are the marine incursions that reached Amazonia during the Miocene and connected western Amazonia with the Caribbean. In the Miocene, large parts of western Amazonia were covered by extensive wetlands that, during high eustatic episodes, were episodically colonised by coastal taxa such as mangroves. In this paper, we hypothesise that some of these mangrove community taxa could adapt to freshwater conditions enriching the modern plant composition of the Amazon drainage basin. To assess the past plant composition in the basin, we statistically analyse the palynological composition of two Miocene sections from western Amazonia that were especially rich in presumed mangrove pollen (Zonocostites ramonae). We identify the pollen taxa that coexisted with this community using clustering methods supported by Kendall’s W coefficient concordance analysis. Our results suggest that at least fourteen taxa are closely associated with Zonocostites ramonae (Cricotriporites guianensis, Deltoidospora adriennis, Psilabrevitricolporites devriesii, Psiladiporites redundantis, Psilamonocolpites amazonicus, P. rinconii, Psilatricolporites crassoexinatus, P. labiatus, P. operculatus, Psilatriporites corstanjei, Retitricolporites kaarsii, Rhoipites guianensis, Rhoipites hispidus, and Tetracolporopollenites transversalis). We also illustrate the pollen of this fossil mangrove, and some of its associated fossil taxa, using light microscopy (LM) and scanning electron microscopy (SEM), and we compare them with potential nearest living relatives (NLR). We found that pollen of the modern mangrove Rhizophora mangle is the NLR of Zonocostites ramonae. Of the three associated taxa, the best analogy is between Psilabrevitricolporites devriesii and Humiria balsamifera, the latter a taxon best known from the coastal restinga vegetation in Brazil and Surinam. Tentatively, we assign Forsteronia spp. as NLR for Cricotriporites guianensis, and we propose Euterpe sp. for Psilamonocolpites rinconii (but also Oenocarpus, Hyospathe, Prestoea, and Sabinaria are affine). Based on this study we propose that, at least for some fossil taxa of the Miocene mangrove environment, there are still NLR or relict species that occur in inland Amazonia and along the South American coastline. We thus conclude that the Amazonian flora, like riverine fauna such as the pink river dolphin (Inia) and selected fish taxa, carry an imprint of the Miocene coastal communities.

亚马逊流域生物多样性极为丰富，但这种多样化的起源仍存在很多争议。植物多样性的可能驱动因素之一是中新世时期到达亚马逊河的海洋入侵，并将西部亚马逊河与加勒比海联系起来。在中新世，亚马逊河西部的大部分地区被广阔的湿地覆盖，在高喜剧时期，这些湿地被沿海类群如红树林流行地定居。在本文中，我们假设其中一些红树林群落分类单元可以适应淡水条件，丰富了亚马逊流域的现代植物组成。为了评估该盆地过去的植物组成，我们对西亚马逊地区两个中新世断层的孢粉学组成进行了统计分析，这些断层特别富含假定的红树林花粉（Zonocostites ramonae）。我们使用肯德尔W系数一致性分析支持的聚类方法，确定与该社区共存的花粉类群。我们的研究结果表明，至少十四类群有着密切的关联Zonocostites ramonae（Cricotriporites花草，Deltoidospora adriennis，Psilabrevitricolporites devriesii，Psiladiporites redundantis，Psilamonocolpites amazonicus，P. rinconii，Psilatricolporites crassoexinatus，P.螈，P.翁，Psilatriporites corstanjei，Retitricolporites kaarsii，Rhoipites guianensis，Rhoipites hispidus和Tetracolporopollenites transversalis）。我们还使用光学显微镜（LM）和扫描电子显微镜（SEM）说明了该化石红树林的花粉及其一些相关的化石类群，并将它们与潜在的近缘亲戚（NLR）进行了比较。我们发现现代红树林Rhizophora mangle的花粉是Zonocostites ramonae的NLR 。在这三个相关的分类单元中，最好的类比是在Psilabrevitricolporites devriesii和Humiria balsamifera之间，后者是沿岸休养地最广为人知的分类单元巴西和苏里南的植被。暂时，我们分配Forsteronia spp。作为Criantriporites guianensis的NLR ，我们提出了Euterpe sp.。适用于Psilamonocolpites rinconii（还有Oenocarpus，Hyspathe，Prestoea和Sabinaria都是仿射的）。根据这项研究，我们建议，至少对于中新世红树林环境的某些化石分类群，内陆亚马逊地区和南美沿岸仍存在NLR或遗迹物种。因此，我们得出这样的结论：亚马逊河植物区系，如河流动物区系，例如粉红色的河豚（伊尼亚）和精选的鱼类群，其中带有中新世沿海社区的烙印。