The enamel microstructure of fossil and extant shrews (Soricidae and Heterosoricidae, Mammalia) and its taxonomical significance

摘要

The enamel microstructure (schmelzmuster) is studied in the trigonid of the lower molars from a representative sample of shrews and some other insectivorous taxa. The schmelzmuster is one-layered in most Soricomorpha and characterized by radial enamel. Some soricids, however, show a highly differentiated and apomorphic two-layered schmelzmuster. A total of six different types of schmelzmuster can be recognized within the Soricidae. Three of these are one-layered and three are two-layered. The one-layered types occur in Crocidosoricinae (including extant Myosoricini), in Crocidurinae, and in Anourosoricinae. These types are fairly similar CO those found in Heterosoricidae and other Soricomorpha. The three remaining types with two layers, however, are restricted CO soricine subfamilies Allosoricinae and Soricinae.