Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Apr 18;13(4):e0193774.
doi: 10.1371/journal.pone.0193774. eCollection 2018.

New data on Amynodontidae (Mammalia, Perissodactyla) from Eastern Europe: Phylogenetic and palaeobiogeographic implications around the Eocene-Oligocene transition

Jérémy Tissier  1   2 , Damien Becker  1   2 , Vlad Codrea  3 , Loïc Costeur  4 , Cristina Fărcaş  5 , Alexandru Solomon  3 , Marton Venczel  6 , Olivier Maridet  1   2
Affiliations

New data on Amynodontidae (Mammalia, Perissodactyla) from Eastern Europe: Phylogenetic and palaeobiogeographic implications around the Eocene-Oligocene transition

Jérémy Tissier et al. PLoS One. .

Abstract

Amynodontidae is a family of Rhinocerotoidea (Mammalia, Perissodactyla) known from the late Early Eocene to the latest Oligocene, in North America and Eurasia. European Amynodontidae are very rare, and all remains belong almost exclusively to a single post-Grande Coupure genus from the Oligocene, Cadurcotherium. The "Grande Coupure" defines an extinctions and dispersal-generated originations event in Europe that is nearly contemporaneous with the Eocene-Oligocene transition. Perissodactyls are one of the major groups affected by this event: Palaeotheriidae went almost extinct during this crisis, whereas Rhinocerotidae appeared for the first time in Europe. Study of fossiliferous Eastern-European localities from this age is crucial for the understanding of this crisis. We report here three new localities of Amynodontidae in Eastern Europe. Two of them are dated from the Eocene (Morlaca, Romania; Dorog, Hungary), whereas the other is either Late Eocene or Early Oligocene (Dobârca, Romania). The skull from this latter locality belongs unexpectedly to the same individual as a previously described mandible attributed to "Cadurcodon" zimborensis. As a result, this specimen can be allocated to its proper locality, Dobârca, and is assigned to a new genus, Sellamynodon gen. nov. It is characterised by an extraordinary growth of the nuchal crest, a unique character among amynodontids. Along with this remarkable material from Dobârca, two specimens from another Romanian locality, Morlaca, have been recently discovered and are dated from the Late Eocene. They belong, as well as new material from Dorog (Middle Eocene, Hungary), to the genus Amynodontopsis, also found in North America. The new Hungarian material represents the earliest occurrence of Amynodontidae in Europe. New phylogenetic hypotheses of Rhinocerotoidea are proposed, including the new material presented here, and show that Amynodontidae may be closer to the polyphyletic family 'Hyracodontidae' than to Rhinocerotidae. Amynodontidae, with their deep preorbital fossa and extremely reduced premolars, display in fact a very derived condition, compared to rhinocerotids.

PubMed Disclaimer

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Geographical setting of the new amynodontid localities in Eastern Europe.
A: Morlaca (Romania), Priabonian. B: Dobârca (Romania), Priabonian-Rupelian. C: Dorog (Hungary), late Lutetian-Bartonian.
Fig 2
Fig 2. Skull of Sellamynodon zimborensis (holotype, UBB MPS 15795), a Late Eocene-Early Oligocene amynodontid from Dobârca (Romania).
Dorsal (A), ventral (B), lateral (C) and occipital (D) views. Skull and associated mandible in lateral view (E). Abbreviations: bc, braincase; boc, basioccipital crest; caf, caudal alar foramen; eap, external auditory pseudomeatus; fm, foramen magnum; fs?, frontals suture?; Fw, frontal width; gf, glenoid fossa; hf, hypoglossal foramen; j, jugal; j-sq, jugal-squamosal suture; jf, jugular foramen; nc, nuchal crest; nt, nuchal tubercle; o, orbit; oc, occipital condyle; of, oval foramen; pf, piriform fenestra; popf, postorbital process of the frontal; popj, postorbital process of the jugal; pp, postglenoid process; ptp, posttympanic process; rs, retromolar space; sc, sagittal crest; smf, stylomastoid foramen; sof, supraorbital foramen; sq, squamosal; tf, temporal fossa; za, zygomatic arch; Zw, zygomatic width.
Fig 3
Fig 3. 3D model in orthographic projection of UBB MPS 15795, holotype of Sellamynodon zimborensis.
Dorsal (A), ventral (B), occipital (C) and lateral (D) views of the skull. Mandible in lateral view (E). 3D models are available at MorphoMuseuM.com [35] along with other specimens described in this publication.
Fig 4
Fig 4. Mandible of Sellamynodon zimborensis (holotype, UBB MPS 15795).
Occlusal (A) and lateral (B) views.
Fig 5
Fig 5. Dentition of UBB MPS 15795, holotype of Sellamynodon zimborensis.
A: Left M3 in occlusal view. B-C: Left lower cheek teeth (p3-m3) in occlusal (B) and lingual (C) views.
Fig 6
Fig 6. Amynodontopsis aff. bodei from Morlaca (Late Eocene; Romania).
Right maxillary (UBB MPS V545) with M1-3 in labial (A), occlusal (B) and lingual (C) views. D: Right mandibular fragment from Morlaca (UBB MPS V546) with m1/2, in labial view. E: Lower right m1/2 from Morlaca (UBB MPS V546) in labial view. F: Lower right m1/2 from Morlaca (UBB MPS V546) in occlusal view.
Fig 7
Fig 7. Amynodontopsis aff. bodei from Dorog (late Middle Eocene; Hungary).
A-B: Right maxillary fragment (HNHM PAL 2017.54.1) with upper M2-3 in labial (A) and occlusal (B) views.
Fig 8
Fig 8. The single most parsimonious tree and the distribution of rhinocerotoids (excluding uninformative characters), scaled in time.
Tree length = 825, CI = 0.30, HI = 0.70, RI = 0.51 and RC = 0.15. Taxa ages based on literature as listed in Table 1. Thick bars represent temporal and spatial distribution of taxa and thick bars with dashed lines have uncertain ages. Geological time scale produced with TSCreator [103]. Numbers at nodes are Bremer support values.
Fig 9
Fig 9. Distribution maps of Amynodontidae and palaeogeographical map reconstructions in Eurasia.
Middle to Late Eocene (A) and Oligocene (B) fossil localities bearing amynodontids. See Table 4 for symbols and colours explanations as well as localities and occurrences references. Palaeogeographical map reconstructions during the Late Eocene (C) and Early Oligocene (D) modified from Ron Blakey (jan.ucc.nau.edu/rcb7/mollglobe.html).
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Prothero DR, Manning E, Hanson CB. The phylogeny of the Rhinocerotoidea (Mammalia, Perissodactyla). Zool J Linn Soc. 1986;87: 341–366. doi: 10.1111/j.1096-3642.1986.tb01340.x - DOI
    1. Wall W. The phylogenetic history and adaptive radiation of the Amynodontidae In: Prothero DR, Schoch RM, editors. The Evolution of Perissodactyls. New-York: Oxford University Press; 1989. pp. 341–354.
    1. Lucas SG. A new amynodontid (Mammalia, Perissodactyla) from the Eocene Clarno Formation, Oregon, and its biochronological significance. PaleoBios. 2006;26: 7–207.
    1. Averianov A, Danilov I, Jin J, Wang Y. A new amynodontid from the Eocene of South China and phylogeny of Amynodontidae (Perissodactyla: Rhinocerotoidea). J Syst Palaeontol. 2016; 1–19. doi: 10.1080/14772019.2016.1256914 - DOI
    1. Xu Y. Amynodonts of Inner Mongolia. Vertebr PalAsiat. 1966;10: 123–190.

Publication types

Grants and funding

This research received support from the SYNTHESYS Project http://www.synthesys.info/ which is financed by European Community Research Infrastructure Action under the FP7 "Capacities" Program (HU-TAF-6724) (JT). DB, LC, OM and JT are financially supported by Swiss National Science Foundation (grant 200021-162359).