0000000000555598
AUTHOR
Gaëlle Labonne
Developmental integration in a functional unit: deciphering processes from adult dental morphology
The evolution of mammalian dentition is constrained by functional necessity and by the non-independence of morphological structures. Efficient chewing implies coherent tooth coordination from development to motion, involving covariation patterns (integration) within dental parts. Using geometric morphometrics, we investigate the modular organization of the highly derived vole dentition. Integration patterns between and within the upper and lower molar rows are analyzed to identify potential modules and their origins (functional and developmental). Results support an integrated adult dentition pattern for both developmental and functional aspects. The integration patterns between opposing mo…
Evolutionary and developmental hypotheses in rodent dentition through time : the adaptive radiation of Arvicolinae (Rodentia)
The evolution of mammalian dentition is defined by profound morphological modifications as occlusion and heterodonty. Among rodents, characterized by a reduced dental formula, arvicolines have a highly derived dentition, with prismatic and hypsodont molars. The aim of this Ph.D thesis is to explore various morphological innovations through developmental and adaptive aspects. Geometric morphometric methods were used on molars, incisors and mandibles to investigate the dynamics of development and evolution of dentition. A developmental model predicting molar proportions is tested and confirmed for the rodent order; it could be also extended to the premolar. The relationship between dental mor…
When less means more: evolutionary and developmental hypotheses in rodent molars.
10 pages; International audience; Tooth number in rodents is an example of reduction in evolution. All rodents have a toothless diastema lacking canine and most premolars present in most other mammals. Whereas some rodent lineages retained one premolar (p4), many others lost it during evolution. Recently, an 'inhibitory cascade' developmental model (IC) has been used to predict how the first molar (m1) influences the number and relative sizes of the following distal molars (m2 and m3). The model does not, however, consider the presence of premolars, and here we examine whether the premolar could influence and constrain molar proportions during development and evolution. By investigating a l…