The evolution of West African Atlantic mangroves from the Late Cretaceous to the present: an evidence-based synthesis of the paleobotanical record

Valentí Rull 

The paleobiogeographic and evolutionary history of tropical West African (WAF) mangroves has yet to be comprehensively reconstructed from the available paleobotanical evidence. This study presents the WAFMA (West AFrican MAngrove) dataset, the fourth regional compilation in an ongoing series aimed at reconstructing the origin and evolution of mangroves worldwide through standardized, evidence-based analyses of biogeographically coherent regions. Following the methodology previously applied to the Caribbean (CARMA), Europe (EURMA) and the Middle East (MESMA), WAFMA integrates all available original fossil records using rigorous taxonomic and bibliographic quality-control criteria, providing the most complete and reliable reconstruction of WAF mangrove history to date. The WAFMA dataset comprises 107 records spanning the Late Cretaceous to the Holocene. It shows that the earliest (Late Cretaceous-Paleocene) WAF communities containing modern mangrove elements consisted exclusively of Nypa, whereas present-like mangrove forests first appeared in the Early Eocene – coinciding with the Paleoceene-Eocene Thermal Maximum (PETM) and the Early Eocene Climatic Optimum (EECO) – and developed during the Middle Eocene with the establishment of Pelliciera-dominated communities accompanied by Acrostichum and Nypa, and the subsequent arrival of Rhizophora in the Late Eocene. The Eocene/Oligocene Transition (EOT) marked the disappearance of Nypa and the rise of Rhizophora as the dominant mangrove-forming tree, although, unlike in the Neotropics, Pelliciera remained an important component throughout the Neogene. Avicennia appeared during the Middle Miocene Climatic Optimum (MMCO), whereas Conocarpus and Laguncularia were incorporated during the Quaternary, when mangrove diversity reached its maximum. Comparison with the Caribbean demonstrates a coherent evolutionary history across the Atlantic-East Pacific (AEP) biogeographic region while revealing distinctive West African features, notably the prolonged persistence of Pelliciera and the absence of major diversity crises or compositional turnovers. WAFMA substantially refines the historical biogeography of Atlantic mangroves, provides a robust regional framework for future global syntheses of mangrove evolution, and identifies priorities for future research.