A new hominin foot from Ethiopia shows multiple Pliocene bipedal adaptations

• Published in: Nature (London) 2012-03, Vol.483 (7391), p.565-569
• Main Authors: Haile-Selassie, Yohannes, Saylor, Beverly Z., Deino, Alan, Levin, Naomi E., Alene, Mulugeta, Latimer, Bruce M.
• Format: Article
• Language: English
• Subjects: 631/181/19/27; 631/181/414; Adaptation, Physiological - physiology; Age; Animals; Biological Evolution; Earth sciences; Earth, ocean, space; Ethiopia; Exact sciences and technology; Foot - anatomy & histology; Foot - physiology; Foot Bones - anatomy & histology; Foot Bones - physiology; Fossil hominids; Fossils; Gait - physiology; Hominidae - anatomy & histology; Hominidae - physiology; Hominids; Humanities and Social Sciences; Humans; Methods; multidisciplinary; Paleontology; Phalanges (Bones); Physiological aspects; Pliocene; Principal Component Analysis; Principal components analysis; Ratios; Science; Science (multidisciplinary); Taxonomy; Vertebrate paleontology; Walking - physiology
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature10922

A newly discovered partial hominin foot skeleton from eastern Africa indicates the presence of more than one hominin locomotor adaptation at the beginning of the Late Pliocene epoch. Here we show that new pedal elements, dated to about 3.4 million years ago, belong to a species that does not match the contemporaneous Australopithecus afarensis in its morphology and inferred locomotor adaptations, but instead are more similar to the earlier Ardipithecus ramidus in possessing an opposable great toe. This not only indicates the presence of more than one hominin species at the beginning of the Late Pliocene of eastern Africa, but also indicates the persistence of a species with Ar. ramidus -like locomotor adaptation into the Late Pliocene. The 3.4-million-year-old partial hominin foot skeleton indicates the coexistence of more than one hominin species between 3 and 4 million years ago, each with its own way of getting around. Fellow travellers: walking with hominins A 3.4-million-year-old partial skeleton of a hominin foot unearthed in Ethiopia offers an intriguing riddle. The only hominin previously known from that date was Australopithecus afarensis (to which 'Lucy' belonged), which was fully bipedal, and had essentially modern feet. The latest specimen, however, shows evidence for an opposable big toe, more like that seen in modern apes or in the hominin Ardipithecus ramidus , which lived one million years earlier. The new find suggests the coexistence of more than one hominin species in the Pliocene epoch, three to four million years ago, each with its own way of getting around.