The brain of Geogale aurita Milne-Edwards and Grandidier 1872 (Tenrecidae, Insectivora).

Macromorphology, composition, and encephalization of the brain of Geogale aurita, a small Madagascan tenrec, were studied. The relative brain size (encephalization) seems to be lower in Geogale than in the Tenrecinae (spiny or bristled tenrecs) which so far have been found to be at the bottom of the encephalization scale of extant mammalian species. Conservative features found in brain macromorphology are e.g. a minute corpus callosum and an uncovered tectum, and such found in brain composition are e.g. an extremely small neocortex and a large medulla oblongata. In all these brain characteristics, Geogale approaches more to the Tenrecinae than to the Oryzorictinae. However, including Geogale in the Tenrecinae would distinctly widen the range of variation of these characters in this subfamily. Therefore, a classification of Geogale in a specific subfamily would be more appropriate.