Extreme tooth enlargement in a new Late Cretaceous rhabdodontid dinosaur from Southern France

Abstract

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.

Tooth development, histology, and enamel microstructure in Changchunsaurus parvus: Implications for dental evolution in ornithopod dinosaurs

“…This pattern is identical to the appearance of hadrosaurid wavy enamel under cross-polarized light ( Fig 4 ). This type of enamel has only been documented elsewhere in dryosauromorph dinosaurs [ 2 , 3 , 22 ], as well as the rhabdodontid Matheronodon provincialis [ 10 ]. To confirm the presence of wavy enamel in Changchunsaurus parvus , we examined the enamel of replacement tooth crowns under SEM ( Fig 5 ).…”

“…The presence of wavy enamel in the shearing teeth of the rhabdodontid Matheronodon provincialis [ 10 ] and now the discovery of wavy enamel in Changchunsaurus parvus casts doubt on previous evolutionary hypotheses regarding the origin of this unique reptilian enamel type ( Fig 8 ). The teeth of C .…”

“… Boxed symbols indicate presence of wavy enamel in Changchunsaurus (this study), Rhabdodontidae [ 10 ], Dryosauridae [ 3 ], Ankylopollexia [ 3 , 4 , 22 ]. …”

“…Ornithischian dinosaurs display an amazing diversity of tooth shapes, sizes, and arrangements to cope with their herbivorous diets [ 2 , 9 , 10 , 13 , 27 – 31 ]. The teeth of most early ornithischian dinosaurs were relatively simple triangular or leaf-shaped teeth for shearing plant material [ 32 ], but hadrosaurid and ceratopsid dinosaurs displayed extensive modifications to their dentitions, forming complex dental batteries for more efficient oral processing.…”

The oldest freshwater crabs: claws on dinosaur bones

“…Along with correlations with charophytes and dinosaur eggshell biozones, a late Campanian age for the locality may confidently be proposed 23,[25][26][27] . The fossil site is mostly known for its vertebrate assemblage, recovered from three different sedimentological sequences and corresponding to newly described 110 dinosaur (titanosaurid sauropod 26,28 ; rhabdodontid ornithopod 29 ) and pterosaur (azhdarchid pterosaur 30 ) taxa, as well as eusuchian crocodilians 27 . Apart from the diapsids, vertebrates consist of disarticulated pleurodiran and cryptodiran turtles, disconnected remains of sarcopterygian and actinopterygian fishes and, chondrichthyan teeth.…”