Tafonomical studies in Iharkút
I.A. Efremov was the first palaeontologist who defined the taphonomy as “the study of transition of animal remains from the biosphere into the lithosphere”…
Menu
Dental histology of the Iharkút crocodiles
The Iharkút locality provided four, in many ways quite different, species of crocodiles, with the most distinct differences in their teeth. Our research project on different teeth was launched in 2017, led by Krisztián Horváth and Edina Prondvai. The aim of this project is to compare dental histology of Iharkutosuchus makadii, Allodaposuchus, Theriosuchus and Doratodon, and to get a better, more detailed understanding of their paleobiology. The four crocodiles lived in nearly the same area, but had different diets. While, for example, the Iharkutosuchus (known only from Iharkút) was a semi-aquatic herbivore-omnivore, Doratodon was a completely terrestrial predator, similar to theropod dinosaurs. Allodaposuchus most closely resembled the crocodiles living today because of its semi-aquatic predatory lifestyle, while Theriosuchus lived near the water, and its posterior dentition were characterized by bulbous crushing teeth, which allowed the consumption of harder, shelled food.
The different teeth raised many questions: What are the microscopic differences in the teeth? What is the structure of tooth enamel, the structure of dentin, cementum? How long did it take for a tooth to develop, how quickly did it alternate?
The teeth are examined mainly with polarizing microscope based on thin sections, but (especially in the case of enamel) it is necessary to use scanning electron microscopy (SEM) and in certain special cases backscattered electron diffraction (EBSD). With the SEM we received a lot of help from the staff of the Hungarian Museum of Natural History, and in the case of SEM and EBSD from the Department of Petrology and Geochemistry of the Eötvös Loránd University.
An SEM image of a tooth of the Iharkutosuchus makadii. Shown at the bottom of the image is the dentin (in some places with dentin tubules), the upper part of the picture shows the enamel (with daily cycle growth lines at the top).
Polarizing microscopic image of a Doratodon tooth with crossed polarizers. The light zone at the bottom left of the image is the enamel. Hence inwards, the lines visible in the dentin (parallel to the enamel-dentin junction) are the daily cycle von Ebner lines, and perpendicular to them are the dentin tubules.
More articles
Phylogenetic relationships of turtles and crocodilians
The Late Cretaceous European paleogeography was largely characterized by a complex archipelago system…
Biomechanical investigation of the skeletal system in birds with some aquatic habits – Evolution on land, in water and in air
Birds originated in the Jurassic, and later diversified occupying different media and environments…
Rare- Earth Element geochemistry of fossil bones and teeth
Bone fossilization can be viewed as the process of recrystallization of biogenic apatite to carbonate fluorapatite (francolite) …
