Olfactory and thermoregulatory capacities in small terrestrial mammals : a turbinal bone approach ; Capacités olfactives et thermorégulatrices des petits mammifères terrestres : une étude des turbines nasales

In most tetrapods, the nasal cavity houses a bony or a cartilaginous system (i.e. turbinals or turbinates) supporting epithelium and sensory organs involved in either olfaction or heat and moisture conservation. Among extant tetrapods, mammals have on average, the largest turbinals to skull length ratio. Despite some studies in primates, Carnivora, bats, lagomorphs as well asrodents, our understanding of the selective pressures affecting turbinals remains imprecise.This PhD aims to unravel the evolutionary processes responsible for the large anatomical and morphological variations of turbinals among mammals. In the course of our work we acquired an extensive dataset of three-dimensional micro-computed tomography scans (micro-CT) in rodents and other small terrestrial mammals. We were then able to statistically test hypotheses linking turbinal morphology to ecology (e.g. diet or ecotype) and evolutionary patterns such asconvergence or evolutionary trade-off (e.g. conflict for space in the nasal cavity between different organs).The present dissertation provides a non-exhaustive review of the olfaction. In the light of our works, we discussed the methodological and conceptual limits of the field. Indeed, olfaction is a complex function relying on multifactorial processes, under various selective pressures. Olfaction may be tackled by resorting to different approaches (e.g. morphology, histology, genomics) and anatomical proxies (e.g. turbinals, olfactory bulb, vomeronasal organ). In thiscontext, our ongoing projects try to refine current functional hypotheses in studying covariation in olfactory-related organs using different anatomical proxies, immunohistochemistry, and transcriptomic. ; La plupart des tétrapodes actuels, possède dans leur cavité nasale, des rouleaux osseux que l'on appelle les turbines (= turbinaux). Parmi eux, les mammifères ont en moyenne les turbines les plus développées et, qui sont généralement divisées en deux catégories : les turbines respiratoires et olfactives. Les turbines respiratoires ...