Schreger pattern analysis of Mammuthus primigenius tusk: Analytical approach and utility

Abstract

Analyses of the characteristic structural Schreger pattern in the dentine of tusks of numerous fossil proboscidean Mammuthus primigenius (Blumenbach, 1799) from five Upper Palaeolithic (Gravettian) Moravian localities (35-25 cal. ka BP) [Předmostí, Pavlov, Dolní Věstonice, Milovice and Napajedla] and one Würmian Croatian locality Viljevacki cret (Donji Miholjac) reveal the microstructure within the dentine. Values of the Schreger angles, the qualitative appearance of the pattern, and the wavelengths in transverse and longitudinal sections of the tusks were determined showing that Schreger angles can reach around 25-40° near the pulp cavity, begin to increase towards the tusk surface (cement-dentine junction - CDJ), and reach a maximum of around 125°. Wavelengths reach maximal values of around 2,175 μm at low Schreger angles, towards the tusk surface becoming shorter and measuring around 1,100 μm. The qualitative pattern appearance depends mainly on the Schreger angle with a so-called 'V' pattern occurring at low angles, that is between 25-70°. At a maximal angle value (approximately from 80° to 125°) the so-called 'C' pattern occurs near the tusk surface. An 'X' pattern occurs with angle values around 70-80° lying between 'V' and 'C' patterns.