Tooth Enamel Microstructure in Megasorex gigas (Merriam, 1897) and Cryptotis magna (Merriam, 1895) from Mexico – In Comparison to the Schmelzmuster in other Shrews

Abstract The enamel microstructure of molars in Mexican soricines Megasorex and Cryptotis is described and compared to the six types of schmelzmuster found in fossil and recent Soricidae. These types of schmelzmuster show a high correlation to the current systematics of Soricidae. In Megasorex, the relatively simple schmelzmuster is dominated by radial enamel. However, a very thin innermost layer of differentiated enamel indicates the beginning of a two-layered schmelzmuster. This corresponds to the Notiosorex-schmelzmuster. The teeth of Megasorex lack pigmentation, which is not reflected in its schmelzmuster. Similarities to the white-toothed Crocidura-schmelzmuster are superficial. Cryptotis has the typical two-layered enamel of derived Soricinae. The specific enamel type of the inner layer and the strong lateral inclination of its prisms represent a new modification of the highly derived Blarina-schmelzmuster.