Tribology in Animal World: Dietary Habits of Lepidosauria Studied via Dental Microwear

Scientists from the Johannes Gutenberg University Mainz are studying the tooth enamel surface of lepidosauria. Lepidosauria are reptiles with overlapping scales and include approximately 7150 species of lizards, snakes, tuatara and amphisbaenians (worm lizards). The enamel wear patterns demonstrate that the teeth of carnivores and herbivores wear down in distinctive patterns. Looking closer shows that the teeth of algae-eating vs. fruit-eating vs. mollusk-eating lepidosauria also have unique wear patterns. This knowledge will prove to be extremely useful when examining the teeth of extinct animals in determining their dietary habits.

The researchers examined the upper teeth of 77 reptile specimens from 23 surviving species found in the wild. The examinations were carried out by inspecting the teeth under a confocal microscope or by creating silicone impressions, which were then imaged. Three-dimensional surface models of the teeth were created in order to examine 46 different enamel wear characteristics.

Results published in the Proceedings of the Royal Society B: Biological Sciences describe the findings regarding the differences in wear patterns on herbivore and carnivore teeth. The research findings clearly show that the animals included in the study could be grouped into different categories of diet based on tooth wear patterns. The teeth of carnivores have only a few shallow farrows while the teeth of frugivores (animals that eat mostly raw fruits, succulent fruit-like vegetables, roots, nuts and seeds) have deep fallows. Of interesting note is the fact that findings of tooth enamel wear regarding mammals is similar to the tooth enamel wear of reptiles. This finding was unexpected as reptiles do not typically chew their food but rather bite off pieces and swallow them whole.

Researchers hope to take these findings and apply them to the study of dinosaurs in order to determine which dinosaurs were truly herbivores and which were not. Researchers also want to apply the findings to the study of synapsids, which were mammal-like animals that dominated the Earth long before the dinosaurs, approximately 310 million years ago. Researchers are fascinated by the fact that some synapsids evolved from carnivores to herbivores and want to determine at what point in time this happened and in which species it occurred.

Further information: Daniela E. Winkler et al. Dental microwear texture reflects dietary tendencies in extant Lepidosauria despite their limited use of oral food processing, Proceedings of the Royal Society B: Biological Sciences (2019). DOI: 10.1098/rspb.2019.0544