Jaw muscles of New World squirrels.

Journal Article (Journal Article)

The jaw, suprahyoid, and extrinsic tongue muscles are described for eight species of New World squirrels, spanning more than an order of magnitude in body mass. Anatomical differences are discussed in the light of body size, natural history, and phylogeny. The relative sizes of different muscles, their orientations, and the shapes and positions of their areas of attachment vary but show few trends in relation to body size. The anatomical differences are likewise not readily explained by the mechanical requirements of the animals' diets, which are similar. The most marked anatomical differences occur in Sciurillus (the pygmy tree squirrel), as well as those genera--Glaucomys (the flying squirrel) and Tamias (the chipmunk)--that are taxonomically most distinct from the tree squirrels. Sciurillus is noteworthy for its unusually small temporalis and an anterior deep masseter that is oriented to assist in retraction of the jaw. Tamias has a more vertically oriented temporalis and greater inclination in the anterior masseter muscles than the other squirrels, features that may be associated with its large diastema and relatively posteriorly situated cheek teeth, which in turn may relate to its having cheek pouches. Our results form a valuable database of information to be used in further studies of functional morphology and phylogeny.

Full Text

Duke Authors

Cited Authors

  • Ball, SS; Roth, VL

Published Date

  • June 1995

Published In

Volume / Issue

  • 224 / 3

Start / End Page

  • 265 - 291

PubMed ID

  • 7541086

Electronic International Standard Serial Number (EISSN)

  • 1097-4687

International Standard Serial Number (ISSN)

  • 0362-2525

Digital Object Identifier (DOI)

  • 10.1002/jmor.1052240303


  • eng