Periodic Reporting for period 1 - GETAGRIP (Evolutionary Trends And GRasping form and function In Primates and other tetrapod lineages)
Reporting period: 2016-01-18 to 2018-01-17
Two main hypotheses have been suggested to explain the origin of manual grasping: 1) grasping may be derived from arboreal locomotion on thin branches. As the importance of the forelimb in body weight support is largely diminished in arboreal animals, the forelimbs are functionally decoupled and can become specialized for novel behaviours. 2) grasping may have originated in the context of the capture of mobile prey which initiates forelimb grasping movements. Both hypotheses are not mutually exclusive and could confer the selective environment driving the evolution of grasping ability and fine manipulation skills.
This project aimed to understand the origin and evolution of manual grasping in tetrapods by studying the morphology of the forelimb in relation to its function and manual grasping behaviour. We tested these two-main hypotheses in three groups of tetrapods showing grasping abilities by studying the morphology, behavior and locomotion in species that are either arboreal or terrestrial and species with different manual grasping abilities. Our results show significant diversity in forelimb morphology related to and arboreal lifestyle in all clades examined. Moreover, behavioral trial suggests that moving objects elicited more manual grasping compared to stationary objects. Overall our results support both the 'arboreal origins' and 'predation' hypotheses and suggest that manual grasping may have originated in different ecological and functional contexts.