Comparative analysis of shrew tooth pigmentation using energy-dispersive X-ray spectroscopy (EDX)

Abstract

The pigment of tooth enamel is an important odontological character for character for assessing Soricidae taxonomy and phylogeny. This paper describes the original observations of ‘pigment patterns’ (PPt) and ‘visible pigment’ (VPg) in fossil beremendiin shrews in light of the “differential pigmentation” found using UV detection and EDX analysis. The term “differential pigmentation” was used to describe the irregular pigmentation on the teeth of extinct Nesiotites (Neomyini). Our analysis of fossil and recent specimens reveals different reasons for differential pigmentation formation. The first reason is related to fossilization, namely, the chemical alterations of the buried specimen. The second reason is related to a developmental disorder, namely, the enamel organ disorder, which locally stops forming the twin enamel layer. Our original results and published data from EDX analysis of the enamel elemental content and SEM-image analysis of the enamel microstructure again raise the question of a relationship between ferruginous pigmentation and enamel microstructure. Further studies of the enamel structure and pigment chemical composition of red-toothed shrews compared to white-toothed shrews are required.