Mecaster fourneli (Deshayes, 1847) (Echinodermata: Echinoidea) from the Turonian (Late Cretaceous) of the Gabonese Coastal Basin: systematics and palaeobiogeographical implications

This study presents a detailed systematic analysis of the irregular echinoid Mecaster fourneli (Deshayes, 1847) from Turonian (Late Cretaceous) deposits of the Gabonese coastal basin. The morphological and biometric study of 26 well-preserved specimens has allowed a precise characterisation of this species, previously mentioned but never described or illustrated in this region. The specimens studied come from three different localities (Gabon Store, Pétro Gabon and Maison Georges Rawiri). Comparative morpho-biometric analysis with populations from Algeria and Peru reveals a remarkable morphological homogeneity despite the geographical distance. The presence of M. fourneli in the Gabonese coastal basin confirms the geographical expansion of this species during the Upper Cretaceous and strengthens the hypothesis of a palaeobiogeographical link between the Mediterranean and West African provinces during the Turonian-Coniacian, probably via a trans-Saharan passage during the major transgressive event of this period.