Testing for Depéret's Rule (Body Size Increase) in Mammals using Combined Extinct and Extant Data.
Whether or not evolutionary lineages in general show a tendency to increase in body size has often been discussed. This tendency has been dubbed "Cope's rule" but because Cope never hypothesized it, we suggest renaming it after Depéret, who formulated it clearly in 1907. Depéret's rule has traditionally been studied using fossil data, but more recently a number of studies have used present-day species. While several paleontological studies of Cenozoic placental mammals have found support for increasing body size, most studies of extant placentals have failed to detect such a trend. Here, we present a method to combine information from present-day species with fossil data in a Bayesian phylogenetic framework. We apply the method to body mass estimates of a large number of extant and extinct mammal species, and find strong support for Depéret's rule. The tendency for size increase appears to be driven not by evolution toward larger size in established species, but by processes related to the emergence of new species. Our analysis shows that complementary data from extant and extinct species can greatly improve inference of macroevolutionary processes.
Department of Ecology and Environmental Science, Umeå University, SE-901 87 Umeå, Sweden; folmer.bokma@emg.umu.se.
Folmer
F
Bokma
UMR 7207, CNRS/MNHN/UPMC, Ecole Pratique des Hautes Etudes, Paris, France;
Marc
M
Godinot
Jurassica Museum, route de Fontenais 21, 2900 Porrentruy, Switzerland;
Olivier
O
Maridet
UMR 7207, CNRS/MNHN/UPMC, Centre de Recherche sur la Paléodiversité et les Paléoenvironments (CR2P), Muséum national d'Histoire naturelle, Département Histoire de la Terre, 57 rue Cuvier, F-75231 Paris Cedex 05, France;
Sandrine
S
Ladevèze
Naturhistorisches Museum Basel, Augustinergasse 2, 4001 Basel, Switzerland; and.
Loïc
L
Costeur
Department of Palaeontology, Royal Belgian Institute of Natural Sciences, 29, rue Vautier, 1000 Brussels, Belgium.
Floréal
F
Solé
UMR 7207, CNRS/MNHN/UPMC, Centre de Recherche sur la Paléodiversité et les Paléoenvironments (CR2P), Muséum national d'Histoire naturelle, Département Histoire de la Terre, 57 rue Cuvier, F-75231 Paris Cedex 05, France;
Emmanuel
E
Gheerbrant
UMR 7207, CNRS/MNHN/UPMC, Centre de Recherche sur la Paléodiversité et les Paléoenvironments (CR2P), Muséum national d'Histoire naturelle, Département Histoire de la Terre, 57 rue Cuvier, F-75231 Paris Cedex 05, France;
Stéphane
S
Peigné
UMR 7207, CNRS/MNHN/UPMC, Centre de Recherche sur la Paléodiversité et les Paléoenvironments (CR2P), Muséum national d'Histoire naturelle, Département Histoire de la Terre, 57 rue Cuvier, F-75231 Paris Cedex 05, France;
Florian
F
Jacques
UMR 7207, CNRS/MNHN/UPMC, Centre de Recherche sur la Paléodiversité et les Paléoenvironments (CR2P), Muséum national d'Histoire naturelle, Département Histoire de la Terre, 57 rue Cuvier, F-75231 Paris Cedex 05, France;
Michel
M
Laurin
D000818:Animals; D005075:Biological Evolution; D049628:Body Size; D053476:Extinction, Biological; D005580:Fossils; D008322:Mammals / Q000033:anatomy & histology* / Q000145:classification*
Body size; Cope's rule; macroevolution; paleontology; phylogenetics