The oldest Cenozoic mammal fauna of Europe: implication of the Hainin reference fauna for mammalian evolution and dispersals during the Paleocene

Abstract

The mammal fauna of Hainin is particularly interesting as the oldest in the Cenozoic of Europe, and the earliest reference level (MP1–5) of the mammalian biochronological scale for the European Palaeogene. This paper summarizes the mammal taxa discovered in the fauna, presents an analysis of the fauna as a whole (relative abundance and species richness), and describes four new eutherians: Belgoryctes thaleri gen. et sp. nov., Eurolestes dupuisi gen. et sp. nov., Quadratodon sigei gen. et sp. nov. and Cingulodon magioncaldai gen. et sp. nov. The assemblage is relatively small (about 400 dental specimens), characterized by a high diversity and abundance of small insectivorous species and very low abundance of ‘plesiadapiforms’ and ‘condylarths’. By comparison with younger European Paleocene faunas, ‘condylarths’ and ‘plesiadapiforms’ became more and more abundant and diverse through the Paleocene but collapsed at the Paleocene–Eocene Boundary. ‘Proteutherians’ declined steadily, while multituberculates remained diverse, although the early Paleocene was populated mainly by Kogaionidae whereas the late Paleocene was dominated by Neoplagiaulacidae. The palaeoecology of Hainin is deduced from the mammal assemblage: the local environment was likely a forested area. Stratigraphically, the Hainin deposits are most likely of late Danian age, and biochronologically its fauna represents a partial equivalent of the North American Torrejonian Land Mammal Age. When compared to younger Paleocene faunas of Europe, the composition of the Hainin fauna reveals that a relatively important intercontinental dispersal of mammals occurred around the Danian–Selandian boundary, roughly corresponding to the Torrejonian–Tiffanian boundary. This dispersal is marked by the arrival in Europe of typically North American taxa such as arctocyonids, plesiadapids and neoplagiaulacid multituberculates. Additional exchanges of lesser magnitude probably also occurred around the Selandian–Thanetian boundary (i.e. during the Tiffanian), although the evidence is less compelling and mainly concerns the plesiadapids Chiromyoides and Plesiadapis.

http://zoobank.org/urn:lsid:zoobank.org:pub:A240BAE2-7446-4DBD-A597-7BEFE58447DF

Keywords:

• systematics
• palaeobiogeography
• biochronology
• palaeoenvironment

Acknowledgements

We thank B. Sigé and M. Vianey-Liaud (Montpellier), C. Dupuis (Mons) and A. Folie (RBINS) for managing the return of the Hainin collection to its home country after a long period of preparation at the University of Montpellier (ISEM, France), and for its definitive deposition at the RBINS. We are grateful to N. Praet (Ghent University) for providing the relative abundances of the mammal species in Cernay, based on collections of the RBINS. We are further indebted to H. Lagnaux (Mons) who performed the wearisome and dangerous fieldwork, as well as the beginning of the first screen washing in Mons, to F. Laurent (Mons) who completed this first screen washing, and to B. Marandat (Montpellier) who tirelessly treated the sediment extracted from the well of Hainin. Finally, we wish warmly to thank Dr Gregg Gunnell (Duke University Lemur Center) for his meaningful advice during the writing of the paper, and his linguistic revisions. This work was funded by the Federal Science Policy Office of Belgium [project BR/121/A3/PalEurAfrica].

Additional information

Funding

This work was funded by the Federal Science Policy Office of Belgium [project BR/121/A3/PalEurAfrica]