Soutenance de thèse de Narimane Chatar
Rue de Pitteurs, 20
4020 Liège Voir la carte
Cette épreuve consistera en la défense publique d’une dissertation intitulée :
« Disparity, evolution, and convergence among felid and felid-like carnivorans ».
This PhD thesis focuses on the disparity, evolution and convergence among two groups of cat-like carnivorans: Felidae and Nimravidae which both developed impressive saber teeth. Despite extensive research on cat-like carnivorans, our understanding of their diversity, adaptation, and evolutionary pathways remains incomplete, often limited to individual clades or the most derived taxa. Leveraging high-precision 3D surface scanning, biomechanical simulations and geometric morphometrics, this PhD project aimed to assess the temporal and spatial disparity of cat-like carnivorans, analyze their cranio-mandibular evolution and functioning, quantify the phenomenon of convergence, and explore the processes shaping their feline phenotype. The study compiled the most extensive dataset of cat-like cranial and mandibular specimens to date, demonstrating a continuum of adaptations, even among saber-toothed forms. The research highlighted a lack of clear distinctions between clades, suggesting a broad range of hunting strategies. Still, some highly derived saber-toothed felids exhibited unique adaptations in their mandibles, already seen at juvenile stages, implying the presence of anchoring or wide-gape mechanisms at early stages of the development. Additionally, the study identified distinct ontogenetic trajectories, increased morphological changes during growth, accelerated evolutionary rates, and unique patterns of cranio-mandibular integration in clades with saber-toothed taxa. These findings provide insight into the development of saber teeth. Finally, cat-like carnivorans have seen a decline in disparity since their radiation in the Miocene, showing that this morphotype was on the brink of collapse long before their complete extinction.
Le Jury sera composé de :
M. B. CHARLIER (Président), Mme et MM. A.C. FABRE (Naturhistorisches Museum Bern), V. FISCHER (Promoteur), J. MACLAREN (Secrétaire), C. MELORO (Liverpool John Moores University), Z.J. TSENG (University of California).