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Keywords:

  • bone cracking;
  • bite strength;
  • finite element modelling

The relative simplicity of the mandible and its functional integration with the upper dentition in carnivorans makes it an ideal subject for functional morphological studies. To compare the mandibular biomechanics of two convergently evolved bone-cracking ecomorphologies, we used finite element modelling to analyse mandibular corpus stress. The bone-cracking spotted hyena Crocuta crocuta was used as a living analogue to the late Miocene percrocutid Dinocrocuta gigantea, using the grey wolf Canis lupus as a molar bone-crushing outgroup. Mandibular stress values during p3, p4, and m1 tooth biting are found to be lowest in Cr. crocuta, and elevated in both Ca. lupus and D. gigantea. However, the stress-dissipation patterns of the pre-m1 corpus are similar between Cr. crocuta and D. gigantea. Lastly, D. gigantea has a relatively weaker corpus at the post-m1 position than either Cr. crocuta or Ca. lupus. These findings suggest that even though stress patterns are similar amongst the bone-cracking ecomorphs, the extinct D. gigantea had a weaker mandibular structure when performing a comparable bone-cracking task as in Cr. crocuta because of its slender post-m1 corpus. Ontogeny could potentially play an important role in strengthening the post-m1 corpus by growth in the dorsoventral axis, and continuous increase in biting performance through adulthood in living Cr. crocuta suggests the possibility of a relatively more delayed development to full bone-cracking capability in D. gigantea.

© 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158, 683–696.