The functional morphology of the postcranium of Ptilocercus and tupaiines (Scandentia, Tupaiidae): Implications for the relationships of primates and other Archontan mammals.
Item
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Title
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The functional morphology of the postcranium of Ptilocercus and tupaiines (Scandentia, Tupaiidae): Implications for the relationships of primates and other Archontan mammals.
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Identifier
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AAI9986373
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identifier
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9986373
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Creator
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Sargis, Eric James.
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Contributor
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Adviser: Frederick S. Szalay
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Date
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2000
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Language
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English
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Publisher
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City University of New York.
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Subject
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Anthropology, Physical | Biology, Anatomy | Biology, Zoology
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Abstract
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In this study, the postcranial morphology of tupaiids was analyzed from both a functional and phylogenetic perspective. The grasping behavior of some tupaiids was also investigated, and Tupaia minor was frequently observed grasping. Arboreal tupaiids, such as Ptlocercus and T. minor, may represent better models for early primates than didelphid marsupials because they are capable of grasping and are more closely related to primates.;The axial skeleton of Ptilocercus exhibits adaptations for a stable thorax that may facilitate bridging locomotion. The vertebral columns of tupaiines are more mobile and allow more flexion and extension of the spine; this increases stride length, which increases speed in bounding mammals like terrestrial tupaiines. The attributes of Ptilocercus ' thorax are probably primitive for Tupaiidae and the ancestral tupaiid was likely arboreal, whereas the tupaiine condition is derived and the ancestral tupaiine was likely terrestrial. Ptilocercus may also be primitive for Archonta, and a stable thorax may have first evolved in an arboreal ancestral archontan. The adaptations for stability of the thorax were retained in volitantians, and a mobile thorax likely evolved in conjunction with the shift to graspleaping in the ancestral euprimate.;The limbs of Ptilocercus are more adapted for arboreality, while those of tupaiines are more adapted for terrestriality. While Ptilocercus' limbs appear to be habitually flexed and exhibit more mobility in their joints, tupaiines are characterized by more extended limbs and more stability in their joints. The latter restricts movements more to the parasagittal plane, which increases the efficiency of terrestrial locomotion. Tupaiine limbs are more adapted for powerful flexion and extension and, consequently, for rapid terrestrial locomotion. Even the most arboreal tupaiines remain similar to their terrestrial relatives, providing strong evidence for the terrestrial ancestry of Tupaiinae.;A character analysis showed that many of Beard's postcranial characters should be interpreted differently when Ptilocercus is used to represent Scandentia. This further reduces the evidence for Primatomorpha, which likely represents an unnatural grouping. Alternatively, Volitantia has been corroborated by several other studies. Hence, the sister taxon of Dermoptera, is likely Chiroptera, not Primates. The relationships of Scandentia and Primates within Archonta remain unclear.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
