title: Assessing the manipulative potentials of monkeys, apes and humans from hand proportions: implications for hand evolution.
abstract: The hand structure possesses a greater potential for performing manipulative skills than is typically observed, whether in humans or non-human anthropoids. However, a precise assessment of the potential manipulative skills of hands has been challenging, which hampers our understanding of the evolution of manipulative abilities in anthropoid hands. Here, we establish a functional model to quantitatively infer the manipulative potentials of anthropoid hands based on hand proportions. Our results reveal a large disparity of manipulative potentials among anthropoid hands. From the aspect of hand proportions, the human hand has the best manipulative potential among anthropoids. However, the species with a manipulative potential closer to that of humans are not our nearest relatives, chimpanzees, but rather, are certain monkey species. In combination with the phylogenetically informed morphometric analyses, our results suggest that the morphological changes of non-human anthropoid hands did not coevolve with the brain to facilitate the manipulative ability during the evolutionary process, although the manipulative ability is a survival skill. The changes in non-human anthropoid hands may have more likely evolved under selective pressure for locomotion than manipulation.
authors.affiliation: Institute of Rehabilitation and Medical Robotics, State Key Lab of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China.
authors.forename: Ming-Jin
authors.identifier: 0000-0002-9722-3870
authors.initials: MJ
authors.lastname: Liu
authors.affiliation: Institute of Rehabilitation and Medical Robotics, State Key Lab of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China chxiong@hust.edu.cn.
authors.forename: Cai-Hua
authors.identifier: 0000-0003-2326-0289
authors.initials: CH
authors.lastname: Xiong
authors.affiliation: Institute of Rehabilitation and Medical Robotics, State Key Lab of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China.
authors.forename: Di
authors.identifier: 0000-0002-0582-3108
authors.initials: D
authors.lastname: Hu
mesh_terms: D000818:Animals; D005075:Biological Evolution; D006225:Hand / Q000033:anatomy & histology*; D000882:Haplorhini; D015186:Hominidae; D006801:Humans; D009048:Motor Skills
keywords: dexterity; functional model; hand proportions; joint mobility; manipulative potential; robotics