Palaeoanthropology: The middle Pliocene gets crowded.

Abstract

New hominin fossils discovered in Ethiopia, dated to between 3.5 million and 3.3 million years ago, suggest that species diversity may have been as high during early human evolution as in later periods. See Article p.483 The Middle Pliocene, between around 3.5 and 3.3 million years ago, seems to have been crucial for hominins living in Africa. There were several different species living there and the period included the first stirrings of tool use and possibly the emergence of the genus Homo. Yohannes Haile-Selassie et al. describe another Middle Pliocene hominin, Australopithecus deyiremida, which lived in Ethiopia at around the same time as Australopithecus afarensis ('Lucy') and other species such as Kenyanthropus platyops in Kenya. Its morphology suggests that some dental features traditionally associated with later genera such as Paranthropus and Homo emerged earlier than previously thought.