Dr. Matthew Mason: Further Information...
University Physiologist Tel: +44 (0)1223 333829, Fax: +44 (0)1223 333840, E-mail: mjm68@cam.ac.uk
Mason, M.J., Bennett, N.C. & Pickford, M. (2018) The middle and inner ears of the Palaeogene golden mole Namachloris: a comparison with extant species. Journal of Morphology 279: 375-395.
Golden moles have very unusual ears, in many cases featuring unusually large ossicles, a complete air-connection between left and right middle ear cavities and the loss of the tensor tympani muscle. Their fossil record is scanty so little is known about the origin and evolution of these characteristics. In this study, we examined through micro-CT scanning some extraordinarily well-preserved fossil golden mole specimens recently found by Martin Pickford in Namibia. Although the exact age of this species, Namachloris arenatans, is disputed, it may be up to 40 million years old. We have compared its middle and inner ears to those of three living species, Amblysomus hottentotus, Huetia leucorhinus and Calcochloris obtusirostris. The fossil species showed what we interpret as primitive characteristics for golden moles in having no complete inter-ear connection, a retained tensor tympani muscle and small ear ossicles. It resembled extant golden moles in that its inner ear had a secondary crus commune but no identifiable canaliculus cochleae. We discuss the implications of these features in terms of golden mole and afrotherian evolution.
This paper is available on the Journal of Morphology website.