Characters from the deciduous dentition and its interest for phylogenetic reconstruction in Hippopotamoidea (Cetartiodactyla: Mammalia)

Helder Gomes Rodrigues (1, 2) , Fabrice Lihoreau (2) , Maeva Orliac (2) , Jean-Renaud Boisserie (3, 4)

1 CR2P - Centre de Recherche en Paléontologie - Paris
2 UMR ISEM - Institut des Sciences de l'Evolution de Montpellier
3 Palevoprim [Poitiers] - Laboratoire de paléontologie, évolution, paléoécosystèmes, paléoprimatologie [UMR 7262]
4 CFEE - Centre Français des Études Ethiopiennes

Abstract Teeth are frequently used in phylogeny in order to better characterize the evolution of extinct mammal species. While most studies have focused on the adult dentition, the consideration of characters from the deciduous dentition could also contribute to reinforce phylogenetic assumptions or disentangle phylogenetic issues. We chose to investigate the characters of the deciduous dentition in cetartiodactyl taxa in relation to the disputed relationships within hippopotamoids, especially the position of Hippopotamidae. We describe the deciduous dentition of 51 species, among a dataset of 70 cetartiodactyls. We noticed that second and third deciduous premolars have a much lower degree of molarization, and are more suitable for coding than fourth deciduous premolars. Thirty-nine resulting characters were thus added to a previously published matrix, and parsimony and maximum-likelihood analyses were performed. Both analyses provided a better resolved topology for most taxa than without these characters, and with better support for most nodes in the parsimony analysis. Moreover, this analysis provides additional characters supporting the hypothesis of an emergence of hippopotamids within bothriodontine anthracotheres from the Palaeogene of Africa. The promising use of characters from the deciduous dentition in phylogeny should allow discussion of the underlying ontogenetic mechanisms at the origin of dental homology.

Mots clés: Anthracotheres; dental ontogeny; homology; maximum-likelihood analysis; molarization; parsimony analyses

Domaines: Systématique, phylogénie et taxonomie

Helder Gomes Rodrigues, Fabrice Lihoreau, Maeva Orliac, Jean-Renaud Boisserie. Characters from the deciduous dentition and its interest for phylogenetic reconstruction in Hippopotamoidea (Cetartiodactyla: Mammalia). Zoological Journal of the Linnean Society, 2021, 193 (2), pp.413-431. ⟨10.1093/zoolinnean/zlaa147⟩. ⟨hal-03405800⟩