Elsevier

Annales de Paléontologie

Volume 104, Issue 3, July–September 2018, Pages 217-229
Annales de Paléontologie

Original article
Rhinocerotidae (Mammalia, Perissodactyla) from the latest Oligocene Thézels locality, SW France, with a special emphasis on Mesaceratherium gaimersheimense Heissig, 1969Rhinocerotidae (Mammalia, Perissodactyla) de l’Oligocène terminal de Thézels, Lot, avec un accent particulier sur Mesaceratherium gaimersheimense Heissig, 1969

https://doi.org/10.1016/j.annpal.2018.06.001Get rights and content

Abstract

A taxonomic revision of the Rhinocerotidae from the latest Oligocene locality of Thézels in SW France is provided, based on comparative description of several hundreds of mandibular, dental, and postcranial specimens. In terms of abundance, the small-sized and slender-limbed rhinocerotine Mesaceratherium gaimersheimense Heissig, 1969 widely outnumbers the medium-sized and shorter-limbed teleoceratine Diaceratherium aff. lemanense. The material from Thézels in particular adds to the knowledge of M. gaimersheimense in providing for the first time valuable information on most elements of its appendicular skeleton, virtually unknown thus far. This work further confirms that M. gaimersheimense is restricted to the latest Oligocene interval, whereas M. paulhiacense (Richard, 1937) also first occurring in latest Oligocene deposits, survives during the earliest Miocene (Aquitanian standard age; Agenian European Land Mammal Age). The Agen area in SW France (type area of the Agenian ELMA) provides a well-documented sequence for latest Oligocene-earliest Miocene rhinocerotids of Western Europe with Thézels (MP30), Paulhiac (MN1), and Laugnac (MN2). Mesaceratherium gaimersheimense shows several postcranial differences with M. paulhiacense (shape of articular facets on central metapodials; slenderer astragalus but less slender metapodials) suggesting a still more cursorial locomotory mode for the latter species.

Résumé

Une révision taxonomique des Rhinocerotidae de l’Oligocène terminal de Thézels (Bassin de la Garonne) est proposée, fondée sur la description comparative de plusieurs centaines de restes mandibulaires, dentaires et postcrâniens. En termes d’abondance, le petit rhinocérotiné Mesaceratherium gaimersheimense Heissig, 1969, aux membres très élancés, domine outrageusement l’autre forme reconnue, le téléocératiné Diaceratherium aff. lemanense, de taille moyenne et aux membres plus trapus. Le matériel de Thézels permet pour la première fois de décrire des éléments postcrâniens attribuables à Mgaimersheimense, dont les caractéristiques étaient jusqu’alors inconnues. Cette étude confirme par ailleurs que Mesaceratherium gaimersheimense disparaît du registre fossile à la limite Oligocène-Miocène, alors que Mesaceratherium paulhiacense (Richard, 1937), dont la plus ancienne mention remonte également à l’Oligocène terminal (MP30), remplace ce dernier au Miocène basal (Aquitanien/Agénien). La région d’Agen, dans le sud-ouest de la France (région type de l’étage mammalien Agénien), fournit une séquence très bien documentée pour les rhinocérotidés de l’intervalle Oligocène terminal – Miocène basal d’Europe occidentale, avec Thézels (MP30), Paulhiac (MN1), et Laugnac (MN2). Mesaceratherium gaimersheimense présente quelques différences avec M. paulhiacense au niveau du postcrânien (astragale moins profond; disposition des facettes sur les métapodes centraux, eux-mêmes moins graciles) suggérant une meilleure adaptation à la course chez ce dernier.

Introduction

The Aquitaine Basin extends on about 40,000 square miles in southwestern France in a triangle limited by the Atlantic Ocean to the west, the Pyrenees to the South and the Massif Central to the Northeast. From Eocene times onward, fluvio-lacustrine deposits originating from the Massif Central and the Pyrenees accumulated and they preserved huge numbers of vertebrate remains (e.g., Richard, 1948). By the end of the Oligocene, sedimentation was mostly of detrital origin close to the Pyrenees and in the centre of the basin (molasses, marls, clays, sandstones) whereas lacustrine sedimentation deposited primarily in the northeastern edge of the basin (e.g., Cieurac limestone; Cavaillé, 1981). In the vicinity of the Thézels village, South of Cahors (Lot department, Fig. 1), the Cieurac limestone has yielded a lenticular body of marly deposits trapping a rich vertebrate fauna. A preliminary list of Thézels mammals was provided by Bonis and Guinot (1987), including rodents, a suoid (Palaeochoerus sp.), ruminants (Dremotherium cf. Guthi and D. cf. quercyi), rhinocerotids (Diaceratherium aff. lemanense and Mesaceratherium cf. gaimersheimense), a hyaenodontid (Hyaenodon leptorhynchus) and four species of amphicyonid (Haplocyon cf. dombrowskii, Haplocyonopsis crassidens, Pseudocyonopsis landesquei, and Ysengrinia sp.), hemicyonid (Cephalogale cf. geoffroyi and Cephalogale aff. Bonali), mustelid (Plesictis genettoides and “Plesictis” milloquensis), and ailurid carnivorans (Amphictis sp.), consistently pointing to a late Oligocene age for the locality (Arvernian European Land Mammal Age [ELMA]). The rodent assemblage includes Eucricetodon thezelensis, Eucricetodon sp.?, Pseudocricetodon sp., Plesiosminthus admyarion, Plesiosminthus sp.?, Issiodoromys bransatensis, Adelomyarion vireti, Rhodanomys aff. transiens, Rhodanomys sp.?, Peridyromys murinus, Heteroxerus paulhiacensis, and Heteroxerus lavocati, as revised by Comte (2000). These rodents have allowed for refining the age of Thézels, now unambiguously assigned to the MP30 reference level, late Arvenian ELMA, i.e., immediately prior to the Oligocene-Miocene transition (∼23.03 Ma; Vandenberghe et al., 2012). We must note the lack of two genera normally present in MP 30, namely Microbunodon and Archaeomys. If not due either to paleoecological reasons or to a taphonomic bias, these absences could correspond to a level slightly younger than Coderet, the last reference level for the Oligocene epoch (MP 30).

As suggested by Bonis and Guinot (1987), Thézels has yielded numerous cranio-mandibular, dental, and postcranial remains referable to two rhinocerotid species: the short-limbed teleoceratine Diaceratherium aff. lemanense, rare in the deposits (approximately 5%), and the long- and slender-limbed Mesaceratherium cf. gaimersheimense (95% in terms of specimen numbers). Remains assigned to D. aff. lemanense were thoroughly described by Michel (1983) and by Brunet et al. (1987). In this work, we will focus on specimens referable to the representative of Mesaceratherium, with a special emphasis on postcranial elements, which remained widely unknown so far.

Section snippets

Material

All Rhinocerotidae specimens from Thézels described here originate from two collections stored on CVCU (University of Poitiers, France). The so-called “old collection” (TheXXX; L. de Bonis’ collection) corresponds to the remains collected during the excavations of the 1970s and 1980s with 446 cranio-mandibular, dental, and postcranial elements. The “new collection” (UP.TH.year.YYY) gathers remains collected by Master students (paleontology, University of Poitiers) in the last decade. This set

Systematic palaeontology

Order Perissodactyla Owen, 1848.

Family Rhinocerotidae Gray, 1821.

Subfamily Rhinocerotinae Gray, 1821.

Tribe Rhinocerotini Gray, 1821.

Subtribe Teleoceratina Hay, 1902.

Genus Diaceratherium Dietrich, 1931.

Type species: Diaceratherium tomerdingense (Dietrich, 1931).

Referred species (our conception): Diaceratherium lemanense (Pomel, 1853); Diaceratherium aurelianense (Nouel, 1866); Diaceratherium asphaltense (Depéret and Douxami, 1902); Diaceratherium aginense (Répelin, 1917); Diaceratherium

Conclusions

Thézels (MP30) yields among the very last Oligocene mammalian faunas in France, just prior to the Oligocene-Miocene transition, as suggested by Bonis and Guinot (1987) and Comte (2000). Regarding rhinocerotids, this assemblage records the last occurrence of Mgaimersheimense Heissig, 1969, a rhinocerotine mostly known from Germany and France (Fig. 7). For the first time, Thézels allows for characterizing most postcranial traits of this species, which were only optimized by phylogenetic

Disclosure of interest

The authors declare that they have no competing interest.

Acknowledgements

The authors are particularly grateful to the Bord family and the W. Gorbenko family. This manuscript has benefited from the wise and constructive remarks of the reviewers, Oscar Sanisidro and Luca Pandolfi. POA would like to thank Emmanuel Robert and Yves Laurent for having provided access to the collections of the Université Claude Bernard Lyon and of the Muséum de Toulouse, respectively. This work has received financial support by the Université de Poitiers and the CNRS (UMR 7262–IPHEP).

References (28)

  • P.-O. Antoine et al.

    Vertébrés de l’Oligocène terminal (MP30) et du Miocène basal (MN1) du métro de Toulouse (SW de la France)

    Comptes Rendus Palevol

    (2006)
  • O. Abel

    Kritische Untersuchungen über die paläogenen Rhinocerotiden Europas

    Abhandlungen der Geologische Reichsanstall, Wien

    (1910)
  • P.-O. Antoine et al.

    A new rhinoceros from the Bugti Hills, Baluchistan, Pakistan: the earliest elasmotheriine

    Palaeontology

    (2000)
  • P.-O. Antoine

    Phylogénie et évolution des Elasmotheriina (Mammalia Rhinocerotidae)

    Mémoires du Muséum National d’Histoire Naturelle

    (2002)
  • P.-O. Antoine et al.

    A brief review of Agenian rhinocerotids in Western Europe

    Swiss Journal of Geosciences

    (2013)
  • P.-O. Antoine et al.

    A revision of Aceratherium blanfordi Lydekker, 1884 (Mammalia: Rhinocerotidae) from the early Miocene of Pakistan: postcranials as a key

    Zoological Journal of the Linnean Society

    (2010)
  • D. Becker et al.

    A new genus of Rhinocerotidae (Mammalia, Perissodactyla) from the Oligocene of Europe

    Journal of Systematic Palaeontology

    (2013)
  • D. Becker et al.

    Diaceratherium lemanense (Rhinocerotidae) from Eschenbach (eastern Switzerland): Systematics, palaeoecology, palaeobiogeography

    Neues Jahrbuch für Geologie und Paläontologie Abhandlungen

    (2009)
  • A. Boada-Saña et al.

    Nouvelles données sur les rhinocéros fossiles de Gannat (Allier, limite Oligocène-Miocène)

    Revue des Sciences Naturelles d’Auvergne

    (2008)
  • L. de Bonis

    Contribution à l’étude des mammifères de l’Aquitanien de l’Agenais. Rongeurs-Carnivores-Périssodactyles

    Mémoires du Muséum National d’Histoire Naturelle

    (1973)
  • L. de Bonis et al.

    Le gisement de Vertébrés de Thézels (Lot) et la limite Oligo-Miocène dans les formations continentales du bassin d’Aquitaine

    Münchner Geowissenschaftliche Abhandlungen

    (1987)
  • M. Brunet et al.

    Les grands Rhinocerotidae de l’Oligocène supérieur et du Miocène inférieur d’Europe occidentale : intérêt biostratigraphique

    Münchner Geowissenschaftliche Abhandlungen

    (1987)
  • A. Cavaillé

    Les calcaires lacustres du Bas-Quercy

    Bulletin de la société de sciences naturelles du Tarn & Garonne 12

    (1981)
  • B. Comte

    Rythme et modalités de l’évolution chez les rongeurs à la fin de l’Oligocène : Leurs relations avec les changements de l’environnement

    Palaeovertebrata

    (2000)
  • Cited by (4)

    View full text