Adaptive Radiation of Capromyid Rodents: Anatomy of the Masticatory Apparatus

The anatomy of jaw, hyoid, and pharyngeal regions of Capromys pilorides, Geocapromys ingrahami, Plagiodontia aedium , and Myocastor coypus indicates that distinct morphological adaptations are associated with jaw function. Chewing in Capromys and Geocapromys is propalinal and bilateral, and these genera have or-thognathous adaptations. Plagiodontia and Myocastor chew obliquely and have plagiognathous adaptations. These adaptations are associated with an adaptive radiation on the islands of the West Indies. It is not possible to establish with certainty whether the endemic Antillean capromyids are more closely related to Myocastor or to an echimyid, but four possible evolutionary sequences are presented to explain the history of the endemic rodents in the Caribbean.