Bushmeat skeletal waste from an Atlantic African rainforest (Equatorial Guinea) as a test for the Mammal Community Structure Analysis in paleoecology

Mammalian Community Structure Analysis (MCSA) is a widely used paleoecological method for reconstructing environments in fossil sites where apes and hominins are present. However, any fossil assemblage is the result of complex ecological and taphonomic processes that may obscure biological interpretation. In this work, we test the validity of the MCSA for the reconstruction of African rain forest environments through an actualistic approach. For this purpose, we compare the living Mammalian Community Structure of the National Park of Monte Alen (MA) and surrounding areas (Equatorial Guinea, Rio Muni) with the one inferred from associations of skeletal remains (ASRs) collected in villages of the area. It was found that in equatorial rain forest contexts, humans are a significant accumulating agent of skeletal remains, in contrast to other accumulating organisms, which are absent. In villages where hunting of wild animals (bushmeat) is regular, a good number of osteological remains from food residues are deposited near the houses. We collected six samples from five villages and treated each of them as "skeletal associations." We also considered a cumulative deposit composed by the total sample of 3153 skeletal remains. Mammalian Community Structure was estimated using three ecovariables: weight, locomotor adaptation, and diet. Cluster and Correspondence Analysis of the three ecological variables validated the fauna of MA as that of an African tropical forest. Next, the ASRs were compared with the fauna of MA. Some of the localities allowed accurate environmental reconstruction; however, three "skeletal associations" do not provide the minimum amount of data needed for their characterization, ecological biases being evident. The skeletal assemblage that best matches the living reference community is the composite sample. From a paleoecological reconstruction viewpoint, the tropical forest signal is conserved when evaluating percentage relationships between the most diagnostic ecovariables, particularly fruit-eating mammals versus carnivores and arboreal mammals. Taken together, the MCSA is effective in detecting African tropical ecosystems.