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The Semifossorial Function of the Forelimb in the Common Rice Tenrec (Oryzorictes hova) and the Streaked Tenrec (Hemicentetes hemispinosus)

Authors


Section of Morphology, Primate Research Institute, Kyoto University, Inuyama, Aichi, Japan

Summary

The forelimb muscles of the two semifossorial species of Tenrecidae (Oryzoryctinae: common rice tenrec; and Tenrecinae: streaked tenrec) were compared macroscopically with those of the unspecialized terrestrial–arboreal species, the Talazac long-tailed tenrec. The structure of the hand was also observed using three-dimensional reconstructed images from computed tomography data. The two semifossorial species had similar muscle weight ratios in the lateral and long heads of M. triceps brachii and M. teres major. A similar hand skeleton structure (in which the second, third and fourth metacarpals and phalanges act as a digging apparatus) was observed in both species. Our observations confirm that both these species have muscular–skeletal adaptations supporting fossorial locomotion. As each species belongs to a monophyletic subfamily within the Tenrecidae isolated in Madagascar, such semifossorial adaptations are assumed to have evolved convergently.

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