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Generalized quadrupeds, committed bipeds, and the shift to open habitats : an evolutionary model of hominid divergence. American Museum novitates ; no. 3250

Show simple item record Sarmiento, Esteban E. en_US 2005-10-06T16:51:50Z 2005-10-06T16:51:50Z 1998 en_US
dc.description 78 p. : ill. ; 26 cm. en_US
dc.description Includes bibliographical references (p. 55-78). en_US
dc.description.abstract "Proposed models of hominid divergence and the currently accepted hominoid phylogeny fail to account for the distinguishing human characters that led anatomists to hypothesize a prepongid or prehominoid divergence of hominids. Because humans share a cautious climbing ancestry with other hominoids, similarities in the anatomy and proportions of the human musculoskeletal structure with those of gorillas and cursorial cercopithecids suggest that hominids underwent selection for terrestrial quadrupedality after their divergence from a common semiarboreal hominoid ancestor. Selection for terrestrial quadrupedality explains generalized monkeylike characters in humans, reconciling anatomical evidence with the currently accepted hominoid phylogeny. By emphasizing limb movements in the sagittal plane and limb elongation, terrestrial quadrupedalism preadapts an arboreal cautious climber to habitual bipedality. Ecological models based on cercopithecine analogies indicate that at least two adaptive stages prior to the elaboration of human material culture must have occurred if hominid divergence progressed from a semiarboreal life-style in a forest or woodland habitat to a committed terrestrial life-style in an open-country habitat. Based on a baboon model, the initial stage consisted of a generalized, widely distributed woodland ape. Predominantly quadrupedal, this ancestor utilized a wide range of behaviors to exploit a wide range of habitats and food resources. Analogous to gelada baboons, the second-stage hominids exhibited a commitment to open habitats while sacrificing generalized behaviors. The fossil evidence for hominid evolution closely fits this postulated model of hominid divergence. With decreasing geologic age, hominid fossils show an increasingly specialized structure and commitment to open habitats. The presence of (1) more than one hominid lineage committed to open habitats, (2) the likelihood of hybrids between different lineages, and (3) a discontinuous and fragmentary fossil record confound fossil phylogenies and the identification of ancestral hominids"--P. 2. en_US
dc.format.extent 11185457 bytes
dc.format.mimetype application/pdf
dc.language eng en_US
dc.language.iso en_US
dc.publisher New York, NY : American Museum of Natural History en_US
dc.relation.ispartofseries American Museum novitates ; no. 3250 en_US
dc.subject.lcc QL1 .A436 no.3250, 1998 en_US
dc.subject.lcsh Human evolution. en_US
dc.subject.lcsh Bipedalism. en_US
dc.subject.lcsh Fossil hominids -- Africa. en_US
dc.subject.lcsh Divergence (Biology) en_US
dc.title Generalized quadrupeds, committed bipeds, and the shift to open habitats : an evolutionary model of hominid divergence. American Museum novitates ; no. 3250 en_US
dc.type text en_US

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  • American Museum Novitates
    Novitates (Latin for "new acquaintances"), published continuously and numbered consecutively since 1921, are short papers that contain descriptions of new forms and reports in zoology, paleontology, and geology. New numbers are published at irregular intervals.

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