Sergio Almécija

Beatriu de Pinós fellow at Department of Vertebrate Paleontology
American Museum of Natural History

Miocene apes, early hominins and the coevolution of bipedalism and precision grasping

Monday, October 3, 2011
AA-G008, 5:00 PM

Abstract

Miocene hominoids are crucial for understanding the evolution of apes and humans. Extant apes represent a decimated and geographically restricted group of primates, but the Miocene has been repeatedly depicted as ‘the planet of the apes’ by many. What we can see now is just a relict of the large diversity of forms that existed in the past. For example, extant chimpanzees, gorillas and orangutans all have an orthograde (upright) body plan in combination with suspensory (arboreal) adaptations, thus the prevailing theory was that these living forms evolved from a common ancestor that possessed those traits. However, what we see from the fossil record in Africa, Europe and Asia (e.g Nacholapithecus, Pierolapithecus, Hispanopithecus, Sivapithecus) is that these early fossil apes do not resemble the modern forms, and there is no modern extant analogue for their locomotor pattern. In fact, extant great apes seem to be very derived (evolutionarily distinct) from the ancestral ape condition, which should limit the ability to make evolutionary inferences about the earliest hominins (human ancestors) on the basis of just extant taxa. Fragmentary remains of early hominins are now known from the late Miocene (6-7 million years ago) of Kenya (Orrorin) and Chad (Sahelanthropus), as well as the early Pliocene (approximately 4.5 million years ago) of Ethiopia (Ardipithecus). Thus, we must look at the immediately preceding Miocene apes, which are more widely distributed and well represented in the fossil record, in order to infer what the last common ancestor of apes and humans might have looked like. Among others, this includes finding clues about why and how bipedalism evolved in humans and its relation to the freeing of the hands from locomotor demands. This, in turn, enabled the evolution of precision grasping and tool use.

Biography

Sergio Almécija has a PhD in Biological Anthropology from the Autonomous University of Barcelona and University of Barcelona. Currently he is a Fulbright postdoctoral fellow at the Vertebrate Paleontology Department, at the American Museum of Natural History (NY). His thesis, entitled “Evolution of the hand in Miocene apes: implications for the appearance of the human hand”, was devoted to study of the evolution of the hand in fossil hominoids and early hominins. His current interest and projects focus on deciphering the role that Miocene apes played in the emergence of early hominins at the end of the Miocene. The raw materials for his research are the postcranial fossil remains from the Miocene hominoids found in Africa, Asia and especially Europe. The latter continent has many exceptional localities situated in the Catalan region ranging from 14 to 9 Ma, where he has focused most of his fieldwork efforts. Furthermore, these sites have provided some of the most interesting partial skeletons of this period.

Readings

• Almécija, Sergio; Alba, David M.; and Moyà-Solà, Salvador. “Pierolapithecus and the functional morphology of Miocene ape hand phalanges: paleobiological and evolutionary implications.” Journal of Human Evolution, 57 (2009) 284-297. [PDF]
• Almécija S, Moyà-Solà S, Alba DM (2010) Early Origin for Human-Like Precision Grasping: A Comparative Study of Pollical Distal Phalanges in FossilHominins. PLoS ONE 5(7): e11727. doi:10.1371/journal.pone.0011727 [PDF]