Microstructure and geochemical features of hard dental tissues of Deltavjatia vjatkensis and Suminia getmanovi Permian tetrapods (Kotelnich site, Kirov region, Russia)

Abstract

The Kotelnich pareiasaur site, one of the richest of the Permian period, is characterized by the unique integrity of fossil vertebrate assemblages and the preservation of bones’ internal structure (including fossil cellular structures) due to their burial features. Pareiasaur and suminia are two most widespread and most frequently encountered representatives of fossil fauna at the Kotelnich site, belonging to the herbivorous form of trophic affiliation. In the present work, a high degree of the structural preservation of the hard dental tissues of pareiasaur and suminia is demonstrated using scanning electron microscopy and energy dispersive X-ray spectroscopy. Fluorapatite composition of tooth tissues is indicated with trace rare earth elements and uranium incorporated from the host rock as a result of diagenetic alteration during fossilization. No secondary mineralization has been found in the pulp chamber uncovered by a cleavage. The features of its primary internal structure are observed such as pseudomorphs of iron-containing minerals over the fibrils of collagen fibers connecting odontoblastic processes with the walls of dentin tubules, as well as spherical pseudomorphs over blood-like cells.