Download Ecole Pratique des Hautes Etudes PhD

Ecole Pratique des Hautes Etudes PhD
Section of Life and Earth sciences
Title: Evolutionary novelties and emergence of dental phenotypes in Mammals.
Host laboratory: EPHE Paléobiodiversité et évolution – UMR 6282 Biogéosciences
Laboratory address:
UMR 6282 uB/CNRS – Biogéosciences
6 bd Gabriel, 2100 Dijon, FRANCE
Phone / Fax
+333 80 39 63 47 / +333 80 39 63 87
PhD supervisors:
Names: Montuire Sophie, Couette Sébastien, Navarro Nicolas
Address: UMR 6282 uB/CNRS Biogéosciences, 6 bd Gabriel, 2100 Dijon, FRANCE
Téléphone /Fax
+333 80 39 63 47 / +333 80 39 63 87
Emails : [email protected], [email protected], [email protected]
Descriptions and objectives
Background –
Mammals display a high dental diversity in terms of number and complexity of teeth.
This diversity attests of the influence of several parameters including diet and
suggests a mammalian morphospace on which shape changes are possible in every
direction. However, morphological changes within lineages seem to be constrained.
Developmental processes producing the phenotypic expression of genetic variation
are under natural selection. Favouring or limiting some directions of change in the
morphospace, these processes will modify the evolutionary capacity on the short and
long time scales. These constraints can influence the diversity of a clade (at a
macroevolutionay level), forcing the accumulation of new species in one peculiar
direction of the morphospace. In the dental raw the eruption of teeth follows an
iterative developmental model in which interactions between teeth are controlled and
lead to a final dental phenotype. Within teeth themselves, interactions occur between
cusps following the same iterations and defining tooth morphology (number, position
and shape of cusps). Some recent works showed that small modifications of cusp
interactions can imply large modifications at the tooth scale, and for instance the
development of new cusps.
Objectives – This subject will focus on two different mammal groups (rodents and
primates) at different scales (population, lineages, clades). Complementary
approaches will be addressed by both groups. Rodents display a reduced variation of
the dental formula but a high diversity of molar form. In primates, the major part of
variation occurs on the number of teeth and number of cusps on each tooth rather
than on their shape. The main goal of this project is to understand the cusp
interactions and their consequences on dental formula and teeth complexity (gains or
losses of cusps and teeth). These variations of complexity will be analysed in the
historic and evolutionary frameworks of the groups, and of the biotic (size, diet…)
and abiotic parameters.
National and international context– The « EPHE -Paléobiodiversité et évolution »
and « UMR uB/CNRS 6282 Biogéosciences » laboratories have national and
international recognition for their knowledge and skills in form analysis. The evolution
of dental morphology in rodents and especially Arvicolinae is an historic and major
topic of the EPHE laboratory since it establishment. These last years, people from
the laboratory developed international collaborations on Evo-Devo themes on teeth.