Primates Defined

McGraw, W. Scott

doi:10.1002/9781444320039.ch13

Cited by 4 publications

(2 citation statements)

References 31 publications

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“…The presence of grasping extremities is one of the ordinal-level defining features of primates (Napier & Napier, 1967;McGraw, 2023).…”

Section: Introductionmentioning

confidence: 99%

“…The presence of grasping extremities is one of the ordinal‐level defining features of primates (Napier & Napier, 1967; McGraw, 2023). Grasping‐related features found in extremities of most primates include relatively long digits, divergent first rays on both the fore‐ and hindlimbs, expanded frictional skin on the volar surfaces of the palms/soles, and digits and flattened nails in lieu of sharp, tapered claws (Cartmill, 1979; Hamrick, 1998; Lemelin, 2000; Lemelin & Schmitt, 2007; Maiolino et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

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Quantitative assessment of grasping strength in platyrrhine monkeys

Young,

Chadwell,

O'Neill

et al. 2024

American Journal of Biological Anthropology

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ObjectivesDespite the longstanding importance of grasping adaptations in theories of primate evolution, quantitative data on primate grasping strength remain rare. We present the results of two studies testing the prediction that callitrichines—given their comparative retreat from a small‐branch environment and specialization for movement and foraging on tree trunks and large boughs—should be characterized by weaker grasping forces and underdeveloped digital flexor muscles relative to other platyrrhines.MethodsFirst, we directly measured manual grasping strength in marmosets (Callithrix jacchus) and squirrel monkeys (Saimiri boliviensis), using a custom‐constructed force transducer. Second, we reanalyzed existing datasets on the fiber architecture of forearm and leg muscles in 12 platyrrhine species, quantifying digital flexor muscle physiological cross‐sectional area (i.e., PCSA, a morphometric proxy of muscle strength) relative to the summed PCSA across all forearm or leg muscles.ResultsCallithrix was characterized by lower mean and maximum grasping forces than Saimiri, and callitrichines as a clade were found to have relatively underdeveloped manual digital flexor muscle PCSA. However, relative pedal digital flexor PCSA did not significantly differ between callitrichines and other platyrrhines.ConclusionsWe found partial support for the hypothesis that variation in predominant substrate usage explains variation in empirical measurements of and morphological correlates of grasping strength in platyrrhines. Future research should extend the work presented here by (1) collecting morphological and empirical metrics of grasping strength in additional primate taxa and (2) extending performance testing to include empirical measures of primate pedal grasping forces as well.

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“…The presence of grasping extremities is one of the ordinal-level defining features of primates (Napier & Napier, 1967;McGraw, 2023).…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantitative assessment of grasping strength in platyrrhine monkeys

Young,

Chadwell,

O'Neill

et al. 2024

American Journal of Biological Anthropology

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Models of Primate Evolution

Sayers

2015

Encyclopedia of Life Sciences

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Models are generalised abstractions or explanatory hypotheses used to organise or understand data. Primates are the order of mammals to which humans belong, and for that reason have attracted considerable attention. Competing models have been proposed to explain the origin of primates, their evolutionary relationships, their unique social and ecological behaviour and their remarkable intelligence and brain complexity. Other models have focused on the origins of perhaps the strangest primate, the human being. All can be examined with ever‐accumulating information from both living and extinct species, and problematic proposals can be discarded or modified. While a considerable amount is known about primate anatomical and behavioural evolution, it is likely that the most comprehensive models regarding many relevant topics have actually yet to be constructed. Key Concepts Model building is key to scientific progress, and is vital for helping to understand primate evolution. The models of primate origins developed to date focus on anatomical features related to locomotion and feeding, as opposed to social or other life variables. There is wide consensus on the broad outline of primate evolutionary relationships, but often less consensus on the recognition of particular genera or species, or relationships between species. The two major approaches to explaining patterns of primate socioecology have focused on identifying environmental and/or physiological determinants; future work should give detailed consideration to both. Models of primate brain evolution have in the past emphasised either complex feeding behaviour or social relationships; some more recent work incorporates these and other factors. Models for human origins and evolution are particularly controversial. Models for human origins (e.g. why hominids walk on two legs) have focused on carrying tools, thermoregulation, reproductive behaviour and other factors. Models of primate evolution are continuously subject to reevaluation as new data from living and fossil species accumulates. Successful models of primate evolution should consider their subjects in a holistic sense, as opposed to focusing on a small subset of anatomical and/or behavioural characters.

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