Evolvability, Limb Morphology, and Primate Origins

Hamrick, Mark W.

doi:10.1007/978-0-387-33507-0_11

Cited by 9 publications

(12 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As reviewed above, for a given hand or foot size, longer fingers or toes effectively increases grasping span, enhancing substrate prehension and arboreal stability (Hamrick, 2007;Kirk et al, 2008;Lemelin, 1999). As reviewed above, for a given hand or foot size, longer fingers or toes effectively increases grasping span, enhancing substrate prehension and arboreal stability (Hamrick, 2007;Kirk et al, 2008;Lemelin, 1999).…”

Section: Onc Lusion S a Nd D I Re Ction S F Or F U T U R E R E S mentioning

confidence: 94%

“…For the first rays, only proximal phalanges were included in the numerator. To be consistent with previous research on mammalian intrinsic hand proportions (Hamrick, 2001(Hamrick, , 2007Kirk et al, 2008;Lemelin, 1999;Lemelin & Grafton, 1998;Napier, 1961;Patel et al, 2009), the length of the distal phalanges were not included in the calculation of phalangeal index. Across mammals, the presence of the ungual (i.e., nail or claw) causes the distal phalanx to often be highly modified relative to the more proximal elements.…”

Section: Measurement Protocolmentioning

confidence: 99%

See 1 more Smart Citation

Grasping primate development: Ontogeny of intrinsic hand and foot proportions in capuchin monkeys (Cebus albifrons and Sapajus apella)

Young

Heard-Booth

2016

American J Phys Anthropol

View full text Add to dashboard Cite

Young primates have relatively large hands and feet for their body size, perhaps enhancing grasping ability. We test the hypothesis that selection for improved grasping ability is responsible for these scaling trends by examining the ontogeny of intrinsic hand and foot proportions in capuchin monkeys (Cebus albifrons and Sapajus apella). If selection for improved grasping ability is responsible for the observed patterns of hand and foot growth in primates, we predicted that fingers and toes would be longer early in life and proportionally decline with age. We measured the lengths of manual and pedal metapodials and phalanges in a mixed-longitudinal radiographic sample. Bone lengths were (a) converted into phalangeal indices (summed non-distal phalangeal length/metapodial length) to test for age-related changes in intrinsic proportions and (b) fit to Gompertz models of growth to test for differences in the dynamics of phalangeal versus metapodial growth. Manual and pedal phalangeal indices nearly universally decreased with age in capuchin monkeys. Growth curve analyses revealed that metapodials generally grew at a faster rate, and for a longer duration, than corresponding phalanges. Our findings are consistent with the hypothesis that primates are under selection for increased grasping ability early in life. Relatively long digits may be functionally adaptive for growing capuchins, permitting a more secure grasp on both caregivers and arboreal supports, as well as facilitating early foraging. Additional studies of primates and other mammals, as well as tests of grasping performance, are required to fully evaluate the adaptive significance of primate hand and foot growth.

show abstract

Section: Onc Lusion S a Nd D I Re Ction S F Or F U T U R E R E S mentioning

confidence: 94%

Section: Measurement Protocolmentioning

confidence: 99%

Grasping primate development: Ontogeny of intrinsic hand and foot proportions in capuchin monkeys (Cebus albifrons and Sapajus apella)

Young

Heard-Booth

2016

American J Phys Anthropol

View full text Add to dashboard Cite

show abstract

“…9 and 23). Thus, the hand proportions typical of modern primates do not reflect an ancestral change in developmental patterning allowing exploitation of the fine branch niche (Hamrick, 2001(Hamrick, , 2007. There was, however, a change in grasp-mechanics of the hand as evidenced by the metacarpophalangeal joints and the evolution of nails rather than claws in all known early euprimates.…”

Section: Functional/adaptive Implicationsmentioning

confidence: 97%

“…Morphological specializations that allow one-handed grasping (prehension) and object manipulation are thought to be key adaptations in primate evolution (Jones, 1916;Haines, 1955;Napier, 1960Napier, , 1961Cartmill, 1974a,b;Beard, 1991, 1993;Jouffroy et al, 1991;Godinot, 1992;Lemelin, 1996;Hamrick, 2001Hamrick, , 2007Bloch and Boyer, 2002;Kirk et al, 2008). However, the distribution of these specializations, their functional significance, and their novelty relative to other arboreal mammals is poorly understood.…”

Section: Introductionmentioning

confidence: 99%

“…Here, we review the evidence from the hands of early fossil primates and their close relatives and discuss alternative ideas for some of the ecological transitions that occurred during early primate evolution. In particular, it has been suggested that hand morphology reflects increasing specialization for either a) locomotion and foraging in a fine-branch niche (Hamrick, 2001(Hamrick, , 2007Bloch and Boyer, 2002;Kirk et al, 2008); b) prehensile clinging on relatively "large" and often vertical supports (e.g., Napier and Walker, 1967;Godinot, 1991), c) manual predation in the fine branch niche in certain lineages derived from a clade of terrestrial/scansorial "olfactory-guided" insectivores (e.g., Cartmill, 1972Cartmill, , 1974aCartmill, ,b, 1992Lemelin, 1996); or d) a "lunging grasp" (Godinot, 2007) predation style similar to that often used by galagos and tarsiers, in which the animal "almost leaps" by rapidly extending its hind limbs while reaching out and grabbing at prey but never disengaging from the substrate.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hands of early primates

Boyer

Yapuncich

Chester

et al. 2013

American J Phys Anthropol

View full text Add to dashboard Cite

Questions surrounding the origin and early evolution of primates continue to be the subject of debate. Though anatomy of the skull and inferred dietary shifts are often the focus, detailed studies of postcrania and inferred locomotor capabilities can also provide crucial data that advance understanding of transitions in early primate evolution. In particular, the hand skeleton includes characteristics thought to reflect foraging, locomotion, and posture. Here we review what is known about the early evolution of primate hands from a comparative perspective that incorporates data from the fossil record. Additionally, we provide new comparative data and documentation of skeletal morphology for Paleogene plesiadapiforms, notharctines, cercamoniines, adapines, and omomyiforms. Finally, we discuss implications of these data for understanding locomotor transitions during the origin and early evolutionary history of primates. Known plesiadapiform species cannot be differentiated from extant primates based on either intrinsic hand proportions or hand-to-body size proportions. Nonetheless, the presence of claws and a different carpometacarpal joint form in plesiadapiforms indicate different grasping mechanics. Notharctines and cercamoniines have intrinsic hand proportions with extremely elongated proximal phalanges and digit rays relative to metacarpals, resembling tarsiers and galagos. But their hand-to-body size proportions are typical of many extant primates (unlike those of tarsiers, and possibly Teilhardina, which have extremely large hands). Non-adapine adapiforms and omomyids exhibit additional carpal features suggesting more limited dorsiflexion, greater ulnar deviation, and a more habitually divergent pollex than observed plesiadapiforms. Together, features differentiating adapiforms and omomyiforms from plesiadapiforms indicate increased reliance on vertical prehensileclinging and grasp-leaping, possibly in combination with predatory behaviors in ancestral euprimates. Am J Phys Anthropol 57:33-78,

show abstract

The befuddling nature of mouse lemur hands and feet at Bezà Mahafaly, SW Madagascar

Agostini

Rasoazanabary

Godfrey

2017

American J Primatol

View full text Add to dashboard Cite

The reddish-gray mouse lemur (Microcebus griseorufus) possesses striking phenotypic and behavioral variation. This project investigates differences in autopod proportions in neighboring populations of M. griseorufus from the Special Reserve at Bezà Mahafaly in southwest Madagascar. One population resides in an environment generally preferred by M. griseorufus-a spiny forest with large-trunked trees, vertically-oriented supports, and more open ground, while the other resides in a gallery forest with abundant small, often horizontal peripheral branches in high canopy. We demonstrate significant interpopulation differences in autopod morphophology despite no evidence of divergence in mitochondrial cytochrome b. We test two hypotheses regarding ultimate causation. The first, based on the Fine Branch Arborealism Hypothesis (FBAH), holds that autopod differences are related to different locomotor practices in the two environments, and the second, based on the Narrow Niche Hypothesis (NNH), holds that the observed differences reflect a relaxation (from ancestral to descendant conditions) of selective pressure for terrestrial locomotion and/or use of large, vertical supports combined with positive selection for locomoting in peripheral branch settings. Our data conform well to FBAH expectations and show some support for the NNH. Individuals from the gallery forest possess disproportionally long posterior digits that facilitate locomotion on small, flexible canopy supports while individuals from the spiny forest possess shorter posterior digits and a longer pollex/hallux that increase functional grasping diameter for large vertical supports and facilitate efficient ground locomotion. Focal individual data confirm differences in how often individuals descend to the ground and use vertical supports. We further show that predispersal juveniles, like adults, possess autopod morphologies suited to their natal forest. We explore two proximate mechanisms that could generate these cheiridial differences. The first posits an in vivo plastic response to different locomotor behaviors, the second posits differences that manifest in early development.

show abstract

Evolvability, Limb Morphology, and Primate Origins

Cited by 9 publications

References 0 publications

Grasping primate development: Ontogeny of intrinsic hand and foot proportions in capuchin monkeys (Cebus albifrons and Sapajus apella)

Grasping primate development: Ontogeny of intrinsic hand and foot proportions in capuchin monkeys (Cebus albifrons and Sapajus apella)

Hands of early primates

The befuddling nature of mouse lemur hands and feet at Bezà Mahafaly, SW Madagascar

Contact Info

Product

Resources

About