Friday, October 27, 2017

[Paleontology • 2017] Matheronodon provincialis • Extreme Tooth Enlargement in A New Late Cretaceous Rhabdodontid Dinosaur from Southern France

  Matheronodon provincialis 
Godefroit, Garcia, Gomez, Stein, Cincotta,  Lefèvre & Valentin, 2017

reconstruction: L. Panzarin

Rhabdodontidae is a successful clade of ornithopod dinosaurs, characteristic of Late Cretaceous continental faunas in Europe. A new rhabdodontid from the late Campanian, of southern France, Matheronodon provincialis gen. et sp. nov., is characterized by the extreme enlargement of both its maxillary and dentary teeth, correlated to a drastic reduction in the number of maxillary teeth (4 per generation in MMS/VBN-02-102). The interalveolar septa on the maxilla are alternately present or resorbed ventrally so as to be able to lodge such enlarged teeth. The rhabdodontid dentition and masticatory apparatus were adapted for producing a strict and powerful shearing action, resembling a pair of scissors. With their relatively simple dentition, contrasting with the sophisticated dental batteries in contemporary hadrosaurids, Matheronodon and other rhabdodontids are tentatively interpreted as specialized consumers of tough plant parts rich in sclerenchyma fibers, such as Sabalites and Pandanites.

Figure 1 Right maxilla of Matheronodon provincialis gen. et sp. nov. (MMS/VBN-02–102; holotype) in dorsal (a), lateral (b), medial (c), and ventral (d) views. (e) Close-up of the second and third maxillary crowns.

Figure 2 Reconstruction of the maxillary dentition of  Matheronodon provincialis gen. et sp. nov. in lateral view from CT scans of MMS/VBN-02-102.

Ornithischia Seeley, 1887
Ornithopoda Marsh, 1881

Iguanodontia Sereno, 1986
Rhabdodontidae Weishampel, Jianu, Csiki, and Norman, 2003

Matheronodon provincialis gen. et sp. nov.

Etymology. Matheron: in honor of Philippe Matheron, who was the first to describe dinosaur remains in Provence; odous (Greek): tooth; provincialis (Latin): from Provence (southern France).

Holotype. MMS/VBN-02-102, a right maxilla; housed in the collections of the Musée du Moulin seigneurial (MMS, Velaux, France).

Horizon and locality. ‘Begudian’ (local stage) sandstones, late Campanian, Late Cretaceous6,8. Velaux-La Bastide Neuve, Aix-en-Provence Basin, Bouches-du-Rhône, southern France.

Diagnosis. Rhabdodontid ornithopod characterized by the following autapomorphies: enlargement of both maxillary and dentary teeth (up to 5 cm in mesio-distal length); reduction of maxillary tooth families (4 per generation in MMS/VBN-02-102); interalveolar septa on the maxilla alternately present or resorbed ventrally, so that one functional tooth is lodged in two paired alveoli; shortened rostral process on the maxilla; broad dorsal shelf along the rostral third of the maxilla; more than 25 vertical and parallel ridges on the labial side of the maxillary teeth.

Figure 3 Isolated teeth of  Matheronodon provincialis gen. et sp. nov.  Left maxillary tooth (MMS/VBN- 09–149a) in labial (a) and lingual (b) views. Right maxillary crown (MMS/VBN-12-22) in labial (c) and lingual (d) views? Right dentary tooth (MMS/VBN-02-11) in lingual (e) and labial (f) views? Left dentary tooth (MMS/VBN-12-A002) in lingual view (g). Scale bars = 2 cm.

Pascal Godefroit, Géraldine Garcia, Bernard Gomez, Koen Stein, Aude Cincotta, Ulysse Lefèvre and Xavier Valentin. 2017. Extreme Tooth Enlargement in A New Late Cretaceous Rhabdodontid Dinosaur from Southern France. Scientific Reports. 7, Article number: 13098.  DOI: 10.1038/s41598-017-13160-2


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