Many studies were performed for several decades about Nigerian maastrichtian sites and other fossiliferous sites of the same epoch in their vicinity, which allow us to reconstruct the marine epicontinental ecosystem and associated coastal ecosystems with a fair amount of accuracy. We begin with a detailed compilation of the results obtained about biotope and taphocenose. So we can try a temporal setting of the Farin-Doutchi sedimentary sequence, possibly in relation with the terminal Cretaceous eruptions of the Indian hot spot of Deccan. The ecological study in the literal sense is based on $183$ species indexed from upper Maastrichtian of Niger, Nigeria and Mali. With such a number of species, we can reconstruct frequency diagrams of the ecosystem, which reveal the domination of Osteichthyes among marine macrofauna, to the detriment of Chondrichthyes and tetrapods. Trophic relations between present marine species, supplemented by some predation marks found on fossil material from In Daman, allow us to reconstruct food sequences of the marine Maastrichtian ecosystem. They are characterized by numerous trophic levels and a very great variety of ecologic behaviours, with rigorous structuring. The marine ecosystem is characterized by record productivity; in this way, it resembles present lagoons or epicontinental ecosystems. As for the biotope, the difference is the absence of the tide, and for the biocenose, there is a much greater taxinomic diversity of big predators. Palynologic studies done by our predecessors allow us to imagine terrestrial life, with vegetable associations of a very modern aspect, dominated by angiospermales, almost looking like present tropical forest systems.