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. (2004b) The middle ear apparatus of the tuco-tuco Ctenomys sociabilis (Rodentia: Ctenomyidae). Journal of Mammalogy 85: 797-805.
Middle ear morphology has been well-described in subterranean rodents such as mole-rats, but very few previous studies had looked at the ears of tuco-tucos, which are South American burrowing rodents related to guinea-pigs. This study represents the first detailed description of the ear of the sociable tuco-tuco. Many of the features of the middle ear, such as the "freely-mobile" ossicular morphology and the lack of a stapedius muscle, are shared with other subterranean mammals, which might lead one to conclude that these features represent convergent adaptations to an underground existence. However, a comparison of the Ctenomys ear with that of more closely related species such as guinea pigs and chinchillas reveals that many of the "subterranean adaptations" of the tuco ear are actually shared with its non-subterranean caviomorph relatives, while unusual features such as the bullet-shaped malleus head and the fused malleo-incudal articulation are also caviomorph characteristics. It is concluded that these features are likely to be plesiomorphic for the caviomorph clade.
This study was extended by Argyle & Mason (2008), who looked at the ears of degus and other South American rodents related to tuco-tucos, comparing these to the ears of more distantly-related rats.
To access this paper via the Journal of Mammalogy website, please click here.
Please contact me if you would like to be sent a reprint copy of this paper.