Rhabdodon

''Rhabdodon'' (meaning "fluted tooth") is a genus of ornithopod dinosaur that lived in Europe approximately 70-66 million years ago in the Late Cretaceous. It is similar in build to a very robust "hypsilophodont" (non-iguanodont ornithopod), though all modern phylogenetic analyses find this to be an unnatural grouping, and ''Rhabdodon'' to be a basal member of Iguanodontia. It was large amongst its relatives, measuring long and weighing , with some specimens possibly reaching up to long.

Discovery

Two species of ''Rhabdodon'' are known, ''Rhabdodon priscus'', the type species, and ''R. septimanicus'' (Buffetaut and Le Loeuff, 1991). ''Rhabdodon'' remains are currently known from southern France, although fragmentary remains from eastern Spain have been assigned to the genus. ''Rhabdodon'' was large compared to its nearest relatives, and indeed one recent paper ( Ősi ''et al.'' (2012)) determined it is larger than the basal rhabdodontid status; from this they suggested that it actually experienced gigantism on the "mainland"; and not insular dwarfism as previous suggested.

Paleobiology

''Rhabdodon'' was probably an important herbivore in Cretaceous Europe. ''Rhabdodon's'' predators include the abelisaurid ''Arcovenator'', and young may have been prey for ''Pyroraptor''.

Paleoecology

''Rhabdodon priscus'' is known from a specimen from the Marnes Rouges Inférieures Formation. The material of ''Rhabdodon priscus'' includes a dentary and many other postcranial remains. More specifically, it is known from the Bellevue layer, which has produced many vertebrate fossils. Even though it produced many vertebrates, the formation only has a scarce record of plants and invertebrates. The non-dinosaurian vertebrates consist of ''Lepisosteus'', an indeterminate turtle, and a crocodile. Dinosaurian fauna from the Marnes Rouges Inférieures Formation include ''Ampelosaurus'', an animal classified as Dromaeosauridae indet., and an indeterminate ankylosaur. The bird '' Gargantuavis philoinos'', and dinosaur eggs have also been recovered.

Another formation ''Rhabdodon priscus'' is known from is Gres de Saint-Chinian. Along with both ''Rhabdodon priscus'', ''Rhabdodon septimanicus'', dinosaur eggs, Nodosauridae indet. (previously known as '' Rhodanosaurus lugdunensis''), Theropoda indet., ''Variraptor mechinorum'', Avialae indet., Enantiornithes indet., and a possible Abelisauridae indet. are known from this formation.

''Rhabdodon priscus'' is one of few vertebrates known from the Gres de Labarre Formation. The only other fossils from the formation belong to ''Ampelosaurus atacis'' and a Nodosauridae indet.

Villalba de la Sierra Formation

''Rhabdodon'' sp. is from the latest Cretaceous aged Lo Hueco region in the Villalba de la Sierra Formation. A study shows that the area around Lo Hueco dates to the late Campanian and early Maastrichtian, although a more recent study revised the later date to the latest Maastrichtian. The study showed that Lo Hueco was near the coast of the Tethys Sea, a large seaway through southern Europe and northern Africa. The area directly on the coast was shown to be a brackish-freshwater aquatic environment, with a muddy flood-plain beside it. Lo Hueco was found to be inside the flood-plain. The flood plain was found to have distributary channels of sand and terrigenous material.

Many dinosaurs have been found in the Villalba de la Sierra Formation, including ''Rhabdodon'' sp. They consist of possible ''Lirainosaurus'' remains, ''Ampelosaurus atacis'', unknown basal euornithopods, probable ankylosaurians, one undetermined dromaeosaurine, and one unknown velociraptorine. The plants known from the formation are represented by carbonized branches and leaves. Invertebrates are solely known from bivalves and gastropods. Fishes from the formation include lepisosteids, and unidentified actinopterygians and teleosteans. Turtle fossils are very common, but only two different groups have been identified, the bothremydids ''Polysternon'' and ''Rosasia'', along with an undetermined Pancryptodiran. Squamate lizards are known only from a few undetermined specimens, and eusuchian crocodiles are known from a specimen with similarities to ''Allodaposuchus'' and '' Musturzabalsuchus''.

Classification

The cladogram below is based on the analysis of Ösi ''et al.'' (2012):

References

Further reading

* Brinkmann, W., 1986. ''Rhabdodon'' Matheron, 1869 (Reptilia, Ornithischia): Proposed conservation by suppression of ''Rhabdodon'' Fleischmann, 1831 (Reptilia, Serpentes). Case 2536. Bulletin of Zoological Nomenclature 43: 269-272
* ICZN, 1988. Opinion 1483. ''Rhabdodon'' Matheron, 1869 (Reptilia, Ornithischia): Conserved. Bulletin of Zoological Nomenclature 45: 85-86

{{Taxonbar, from=Q428508

Iguanodonts
Maastrichtian life
Late Cretaceous dinosaurs of Europe
Cretaceous France
Fossils of France
Cretaceous Romania
Fossils of Romania
Cretaceous Spain
Fossils of Spain
Tremp Formation
Fossil taxa described in 1869
Ornithischian genera