The TRIDENT project:

Animals interact with their habitat when feeding. In order to reconstruct the ecology of an animal, tracking its diet is critical. Most soft tissues of a deceased animal are rarely well preserved in the fossil record. Frequently teeth are one of the only well preserved organs of an animal’s digestive system and, as such, can be valuable sources of data for reconstructing the ecology of a fossilized animal. Certain teeth characteristics can roughly indicate what an animal has eaten. These characteristics are incisor size, canine shape, enamel thickness, ratio of the molar to premolar length, and molar hypsodonty index (see Figure). However these methods do not reflect what an animal has indeed eaten but what is able to eat. Alternative approaches (independent from tooth shape) in paleontology allow species independent reconstruction of the dietary preferences of extinct species and environments. Among these techniques is Dental Microwear Textural Analysis (DMTA, see Figure).

Because microwear on enamel surface mainly depends on the physical characteristics of the diet, dental microwear analyses allows tracking the food eaten by an animal independently from its tooth morphology. Despite some studies on present-day species (Rivals and Solounias, 2007; Teaford, 1988; Merceron et al., 2004), we know very little about the relation between dental microwear textures, food composition and properties. For instance, can microwear analyses reflect small proportions of fallback foods, the items consumed over a short period of time when preferred food is absent ? Also, we know very little about the turnover of dental microwear when a given individual switches from a diet to another. These elements are crucial points to better interpret data for a fossil population with individuals randomly sampled. The TRIDENT project will overcome these obstacles.

TRIDENT is an interdisciplinary project combining human and technic competences in agronomy (Mourier Farm Station), tribology (Institut Pprime) and paleontology (iPHEP). TRIDENT aims at investigating the ecology of herbivorous mammals through dietary behaviour analysis. For this, the project will develop dietary reconstruction models thanks to new technical advances of textural surface analysis applied to a dataset resulting from an ambitious controlled-food testing on domestic sheep.

Figure. Mandible and teeth morphologies reflect what an animal can eat whereas the dental microwear textures on enamel reflect what the animal has indeed ingested and eaten.