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| Biknevicius, A.R.; Leigh, S.R. | |
| Patterns of growth of the mandibular corpus in spotted hyenas (_Crocuta crocuta_) and cougars (_Puma concolor_) | |
| 1997 Zoological Journal of the Linnean Society (128): 139-161 | |
DiVerences in jaw morphology among adult carnivorans are well established, but the ontogenetic mechanisms by which these diVerences arise are largely unexplored. Mandibular ontogeny in _Crocuta crocuta _and _Puma concolor _is analysed biomechanically using principles of beam theory. In each species, the development of cross-sectional properties of the mandibular corpus associated with rigidity under loading follows a biphasic pattern of growth. In early postnatal growth, deposition of cortical bone appears to be constrained by the overall weaker tissue with which juvenile skeletons are constructed and by the need to volumetrically accommodate the developing teeth within their bony crypts. Thus, this stage of growth is characterized by a net periosteal deposition of bone and a swelling of the medullary cavity. In late postnatal growth, the constraints on endosteal deposition of bone are relieved as the permanent teeth erupt; thus, cortical thicknesses increase sharply by periosteal expansion as well as medullary contraction. Finally, it is noted that basic diVerences in jaw construction between _Crocuta _and _Puma _appear to develop prenatally as they are largely in place at birth. Hence, postnatal development enhances, but does not soley contribute to, the biomechanical diVerences in the jaws of these species. |
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