Thèse : Long bone inner and outer adaptations in sauropodomorph dinosaurs

Towards extreme gigantism - Long bone inner and outer adaptations in sauropodomorph dinosaurs

Secteur d'activité : Recherche et Enseignement

Employeur : MNHN

Contact :

Localisation : Paris

Start : 01/09/2017
Duration : 3 years

Description :

Giant forms evolved convergently in various amniote lineages. Among them, the largest land forms were sauropod dinosaurs. These forms naturally show adaptations for high body mass support and propulsion, which is naturally reflected in their bone design. Sauropodomorph dinosaurs offer to analyze in parallel increasing graviportal adaptations and the acquisition of a quadrupedal posture in their evolutionary history. Increase in body size seems to have occurred quickly in sauropodomorphs, from small ancestral forms to ancestral sauropods weighting from 1 to 10 tons and to have been accompanied by changes in limb and bone proportions. Of particular interest is the supposed progressive shift in function of the forelimb from stronger grasping adaptations in the smallest forms to dominant and then exclusive locomotor function in the largest ones. The aim here will be to focus on the transition from small forms considered either obligate or facultative bipeds to giant quadrupedal forms but also to analyze the differences between three major sauropod groups with distinct locomotor specializations: the diplodocoids, basal macronarians, and titanosaurians.

This project will enable to better understand the link between outer and inner bone structure and the functional requirements associated with high body mass support, and help us to understand how these giant land animals could locomote. This project will necessitate performing 3D geometric morphometric analyses (after acquisition by photogrammetry, surface scanning or microtomography) on limb long bones of a large sample of sauropodomorph dinosaurs in order to perform a detailed comparison of bone shape. In addition, for the bones scanned using microtomography, the microstructure will be analyzed in 2D (sections) and, when possible, in 3D.
This PhD is part of an ERC project whose larger objective is to model the relationships between bone morphology, microanatomy and the functional requirements of body support and locomotion in graviportal taxa through amniote evolutionary history.
 
Financial information :
The PhD will be financed as part of an ERC project. The material necessary for this project is present in the collections of various museums. If many specimens are available in the collections of the MNHN, visits to several museums will be required in addition to loans. All the required technical support is available at the MNHN.
 
Candidate profile :
Student with a Master in Biological Sciences and some experience in 3D data analysis; dynamic, able to work autonomously as well as in a team; good level in spoken and written English.
Please send a CV and a motivation letter by e-mail to houssaye@mnhn.fr. The copy of your Master Thesis would also be welcome.
 
Deadline : 01/04/2017.