Skip to Main content Skip to Navigation
Theses

Multiscale variation of 3D tooth forms in selachians and developmental and evolutionary inferences : Odyssey of a scyliorhinid tooth

Abstract : Teeth are serial structures whose evolutionary and developmental history is intricately linked with the emergence of mineralised tissues in vertebrates. Teeth display a broad range of forms and differ in developmental patterns in extant vertebrates, making them remarkable elements to study species diversification. Selachian teeth renew permanently and display morphologies that are correlated with mating and trophic behaviours.This work first assesses the variation of tooth forms in two scyliorhinids by using 3D geometric morphometrics and machine learning. The emergence of gynandric heterodonty is detailed for the first time along the ontogeny of sharks and it is demonstrated that this natural variation should be first assessed before performing species discrimination.This work also questions the role of specific proteins on the acquisition of a shark tooth form over development. Functional tests suggest an impact of Shh and Fgf3 in the cusp morphogenesis and in the mineralisation process. These proteins are promising explanatory variables to the inter- and intraspecific tooth differences observed, leading to hypotheses on their role in the evolution of structures with speciation and trophic and mating behaviours.Histological data on extant chondrichthyan vertebrae finally highlight the unsuspected proportion of extant elasmobranchs exhibiting fibrous mineralisation in the neural arches, a bone-like tissue which occurrence had long been refuted in this group. Evolutionary considerations are discussed in the light of the evolution of jawed vertebrates and question on the ecological factors that led particular tissues to be restricted to specific shark and batoid groups.
Complete list of metadata

https://tel.archives-ouvertes.fr/tel-03279588
Contributor : Abes Star :  Contact
Submitted on : Tuesday, July 6, 2021 - 3:44:31 PM
Last modification on : Wednesday, September 8, 2021 - 10:30:01 AM

File

BERIO_Fidji_2021LYSEN010_These...
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-03279588, version 1

Citation

Fidji Berio. Multiscale variation of 3D tooth forms in selachians and developmental and evolutionary inferences : Odyssey of a scyliorhinid tooth. Populations and Evolution [q-bio.PE]. Université de Lyon, 2021. English. ⟨NNT : 2021LYSEN010⟩. ⟨tel-03279588⟩

Share

Metrics

Record views

81

Files downloads

147