Proconsul, a genus of early apes linked to the origin of the ape-human lineage, lived in a dense tropical forest, according to research published in Nature Communications. Previous evidence has suggested that Proconsul may have lived in a variety of habitats, including open spaces, but this work helps to confirm that some members of the genus definitively lived in dense, closed-canopy forests. This finding indicates the importance of arboreal settings in the early evolution of distant human ancestors.
Hominoids originated and diversified in Afro-Arabia 28-18 million years ago during the late Oligocene and Early Miocene. Knowledge of the environment that these ancestral apes lived in can help us to understand the selective pressures that gave rise to early humans. There are, however, very few instances where well-preserved fossil hominoid remains co-occur with a discrete set of palaeoenvironmental indicators, making it difficult to directly tie individual species to specific habitats.
Lauren Michel and colleagues analysed Early Miocene environmental indicators, such as fossil plants and fossil soils, and remains of Proconsul from Rusinga Island, in Kenya - an area that contains key sources of palaeobiological information from the Early Miocene. The authors report that the fossil remains include densely clustered tree stumps, and well preserved leaves from predominantly evergreen species. The palaeoclimate data suggest that the annual temperature ranged from 22.6-34.5oC, and the precipitation was relatively high. Together, this evidence implies that Proconsul lived in dense tropical forest set in a warm, wet, and seasonal local climate in equatorial Africa.
This work supports the hypothesis that Proconsul lived in closed canopy forests and also highlights that these hominoids were already adapted to live in both open and closed conditions.