Paleobiology; January 2008; v. 34; no. 1;
p. 46-64; DOI: 10.1666/06052.1
© 2008 Paleontological Society
Topographic maps applied to comparative molar morphology: the case of murine and cricetine dental plans (Rodentia, Muroidea)
Vincent Lazzari1,
Paul Tafforeau2,
Jean-Pierre Aguilar1 and
Jacques Michaux3
1 Vincent Lazzari and Jean Pierre Aguilar. UMR CNRS 5554, Institut des Sciences de l'Evolution, BP064, Université de Montpellier II, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France. lazzari{at}isem.univ-montp2.fr
2 Paul Tafforeau. European Synchrotron Radiation Facility, BP220, 6 rue Jules Horowitz, 38043 Grenoble Cedex, France. tafforea{at}esrf.fr
3 Jacques Michaux. UMR CNRS 5554, Institut des Sciences de l'Evolution, BP 064, Ecole Pratique des Hautes Etudes, Université Montpellier II , Place Eugène Bataillon, 34095 Montpellier cedex 5, France. michaux{at}isem.univ-montp2.fr
We developed a new method to generate topographic maps of tooth crowns from X-ray synchrotron microtomographic data. Maps are drawn after cervix-plane orientation of tooth image stacks, without the need for a geographic information system. Classical topographic maps with contour lines are complemented by slope maps and angularity maps. Cartography allows precise comparisons of cusps morphologies, and quantification of the directions of cusp axis elongation and slope. Application of this method to muroid rodents with cricetine and murine dental patterns reveals clear-cut differences in cusps morphology that are indicative of the direction of the chewing movement, in agreement with wear facet analyses. Rodents with a murine dental pattern were derived from ancestors with a cricetine pattern, and their origin is associated with important changes in cusp morphology and organization. In order to understand such evolutionary change, our investigation is applied to a sample of extant and fossil muroid rodents that are characterized by either a murine dental plan or a cricetine one, or a dental pattern intermediate between those of cricetines and murines.
Copyright © 2008 by Paleontological Society