''Rhabdodon'' (meaning "fluted tooth") is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

ornithopod Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (), that started out as small, bipedal running grazers and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous w ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

that lived in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

approximately 70-66 million years ago in the Late

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

. 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 France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

, 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 ''Arcovenator'' ("Arc hunter") is an extinct genus of abelisaurid theropod dinosaurs hailing from the Late Cretaceous of France. The type and only described species is ''Arcovenator escotae''. Description Though shallower, the nearly complet ...

'', and young may have been prey for ''

Pyroraptor ''Pyroraptor'' (meaning "fire thief") is an extinct genus of paravian dinosaur, probably a dromaeosaurid or unenlagiid (considering that unenlagiids are a separate family), from the Late Cretaceous Ibero-Armorican island, of what is now souther ...

''.

Paleoecology

''Rhabdodon priscus'' is known from a specimen from the

Marnes Rouges Inférieures Formation The Marnes Rouges Inférieures Formation is a Late Cretaceous geologic formation found in the French Pyrenees. It predominantly consists of red mustone, with minor brown mudstone and sandstone.Fondevilla et al., 2016 Dinosaurs, dinosaur eggs and ...

. 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. Rhabdodon septimanicus

Another formation ''Rhabdodon priscus'' is known from is

Gres de Saint-Chinian The Gres de Saint-Chinian is a geological formation in Aude and Hérault, France whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.Weishampel, David B; et al. (2004). ...

. Along with both ''Rhabdodon priscus'', ''Rhabdodon septimanicus'', dinosaur eggs,

Nodosauridae Nodosauridae is a family of ankylosaurian dinosaurs, from the Late Jurassic to the Late Cretaceous period in what is now North America, South America, Europe, and Asia. Description Nodosaurids, like their close relatives the ankylosaurids ...

indet. (previously known as '' Rhodanosaurus lugdunensis''), Theropoda indet., '' Variraptor mechinorum'',

Avialae Avialae ("bird wings") is a clade containing the only living dinosaurs, the birds. It is usually defined as all theropod dinosaurs more closely related to birds (Aves) than to deinonychosaurs, though alternative definitions are occasionally use ...

indet.,

Enantiornithes The Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct avialans ("birds" in the broad sense), the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and cla ...

indet., and a possible

Abelisauridae Abelisauridae (meaning "Abel's lizards") is a family (or clade) of ceratosaurian theropod dinosaurs. Abelisaurids thrived during the Cretaceous period, on the ancient southern supercontinent of Gondwana, and today their fossil remains are fou ...

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 The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campani ...

and early

Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the inte ...

, 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 The Tethys Ocean ( el, Τηθύς ''Tēthús''), also called the Tethys Sea or the Neo-Tethys, was a prehistoric ocean that covered most of the Earth during much of the Mesozoic Era and early Cenozoic Era, located between the ancient continents ...

, 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

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of marine and freshwater Mollusca, molluscs that have laterally compressed bodies enclosed by a shell consisting of two hing ...

s and

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

s. Fishes from the formation include lepisosteids, and unidentified

actinopterygian Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or ho ...

s and

teleostean Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or ho ...

s. 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):

Discovery

Paleobiology

Paleoecology

Villalba de la Sierra Formation

Classification

References

Further reading