New material ofEpiaceratheriumand a new species ofMesaceratheriumclear up the phylogeny of early Rhinocerotidae (Perissodactyla)

Abstract

Reduction of the anterior dentition (i.e. incisors and canines) is a major adaptative trait of the Rhinocerotidae among Perissodactyla. However, the corresponding evolutionary sequence was lacking a robust phylogenetic frame to support it thus far. Here, we describe a new Oligocene species of Rhinocerotinae, Mesaceratherium sp. nov. from the Swiss locality of Bumbach (MP25 reference level). In addition, we identify the only known complete mandible of Epiaceratherium magnum , an early-branching rhinocerotid, as well as one of the earliest European rhinoceroses. We also compute a parsimony analysis based on morpho-anatomical characters to assess their phylogenetic position and elucidate the early evolution of the Rhinocerotidae. Our results allow to propose a new scenario for the reduction of the anterior dentition in which upper and lower dentitions would have undergone distinct evolutionary trajectories.

Reconstructing the phylogeny of the hornless rhinoceros Aceratheriinae

“…Mesaceratherium from the late Oligocene of Eurasia has long been considered the earliest genus of Aceratheriini, with less molarized premolars (Heissig, 1969). Antoine et al (2010) placed it as a sensu lato acerathere, and in the newest paper this genus and some other Paleogene rhinoceroses were placed as an early clade of Rhinocerotinae (Tissier et al, 2020). Given its enlarged upper and lower incisors, like Aprotodon, we suggested Mesaceratherium should be an acerathere, consistent with the present analyses.…”

New species, revision, and phylogeny of Ronzotherium Aymard, 1854 (Perissodactyla, Rhinocerotidae)

“…To test the monophyly of Ronzotherium and to understand its systematic position within the early Rhinocerotidae, we included a branching group (see Antoine 2002), comprising some of the earliest known Rhinocerotidae: the Late Eocene North American taxa Teletaceras radinskyi Hanson, 1989, Penetrigonias dakotensis (Peterson, 1920, Trigonias osborni Lucas, 1900 andrepresentatives of Epiaceratherium Abel, 1910, comprising the Asian E. naduongense Böhme, Aiglstorfer, Antoine, Appel, Havlik, Métais, Laq, Schneider, Setzer, Tappert, Dang, Uhl & Prieto, 2013 and the European E. bolcense Abel, 1910, E. magnum Uhlig, 1999 andE. delemontense , according to Tissier et al (2020). We also included rhinocerotids ranging from the Oligocene to the earliest Miocene: Molassitherium albigense (Roman, 1912), Mesaceratherium gaimersheimense , M. welcommi Antoine & Downing, 2010and M. paulhiacense (Richard, 1937, Pleuroceros pleuroceros (Duvernoy, 1853) and P. blanfordi Lydekker, 1884, Protaceratherium minutum Abel, 1910, Subhyracodon occidentalis (Leidy, 1850, Diceratherium armatum Marsh, 1875 and Diaceratherium tomerdingense Dietrich, 1931.…”

Spatio-temporal diversity of dietary preferences and stress sensibilities of early and middle Miocene Rhinocerotidae from Eurasia: Impact of climate changes

“…Phylogenetic relationships follow formal parsimony analyses (Antoine, 2002; Antoine et al, 2010, 2022; Becker et al, 2013; Tissier et al, 2020). …”

“…Figure 6: Prevalence of hypoplasia by locality, species and tooth locus plotted against phylogeny Phylogenetic relationships follow formal parsimony analyses(Antoine, 2002;Antoine et al, 2010Antoine et al, , 2022Becker et al, 2013;Tissier et al, 2020).…”

“…Figure 6: Prevalence of hypoplasia by locality, species and tooth locus plotted against phylogeny Phylogenetic relationships follow formal parsimony analyses(Antoine, 2002;Antoine et al, 2010Antoine et al, , 2022Becker et al, 2013;Tissier et al, 2020).Subtribes colored in blue: Teleoceratina, in green: Rhinocerotina; in yellow: Aceratheriina, in pink: stem Rhinocerotinae, and in orange: Elasmotheriina Dark colors: hypoplastic teeth; Light colors: unaffected teeth…”