Evolution and function of the hominin forefoot
Autor: | Matthew W. Tocheri, William L. Jungers, Caley M. Orr, Peter J. Fernández, Sergio Almécija, Louise N. Leakey, Carrie S. Mongle, Biren A. Patel, Daniel J. Proctor |
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Jazyk: | angličtina |
Rok vydání: | 2018 |
Předmět: |
0301 basic medicine
Most recent common ancestor Multidisciplinary biology Ardipithecus ramidus ved/biology Forefoot ved/biology.organism_classification_rank.species Morphology (biology) Hominidae Biological Sciences biology.organism_classification Biological Evolution body regions 03 medical and health sciences 030104 developmental biology Human evolution Evolutionary biology biology.animal Ardipithecus Animals Primate Bipedalism Metatarsal Bones Phylogeny |
Popis: | The primate foot functions as a grasping organ. As such, its bones, soft tissues, and joints evolved to maximize power and stability in a variety of grasping configurations. Humans are the obvious exception to this primate pattern, with feet that evolved to support the unique biomechanical demands of bipedal locomotion. Of key functional importance to bipedalism is the morphology of the joints at the forefoot, known as the metatarsophalangeal joints (MTPJs), but a comprehensive analysis of hominin MTPJ morphology is currently lacking. Here we present the results of a multivariate shape and Bayesian phylogenetic comparative analyses of metatarsals (MTs) from a broad selection of anthropoid primates (including fossil apes and stem catarrhines) and most of the early hominin pedal fossil record, including the oldest hominin for which good pedal remains exist, Ardipithecus ramidus. Results corroborate the importance of specific bony morphologies such as dorsal MT head expansion and “doming” to the evolution of terrestrial bipedalism in hominins. Further, our evolutionary models reveal that the MT1 of Ar. ramidus shifts away from the reconstructed optimum of our last common ancestor with apes, but not necessarily in the direction of modern humans. However, the lateral rays of Ar. ramidus are transformed in a more human-like direction, suggesting that they were the digits first recruited by hominins into the primary role of terrestrial propulsion. This pattern of evolutionary change is seen consistently throughout the evolution of the foot, highlighting the mosaic nature of pedal evolution and the emergence of a derived, modern hallux relatively late in human evolution. |
Databáze: | OpenAIRE |
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