Euronychodon ("European claw tooth") is the name given to a
genus of
coelurosaurdinosaur from the Late
Cretaceous of
Europe and
Asia. Euronychodon is known from teeth only. These are similar to those of another coelurosaur tooth genus, Paronychodon.
Species
Two species of Euronychodon have been named to date.
E. portucalensis (named for
Portugal, from Portucale, an old name of
Porto): the remains consist of three teeth. In 1988 referred to Paronychodon lacustris,[1] they were later considered diagnostic enough for them to represent a distinct genus and species. They were found at the locality of
Taveiro, dated as
Campanian-
Maastrichtian (about 70 million years old). The
type species of Euronychodon, E. portucalensis was named and described in 1991 by
Miguel Telles Antunes and
Denise Sigogneau-Russell. The generic name is a contraction of "Europe" and Paronychodon. The
holotypeCEPUNL TV 20, is one of the teeth. It is 1.8 millimetres long, recurved and strongly elongated with a D-shaped cross-section. The other two teeth, CEPUNL TV 18 and CEPUNL TV 19, are the
paratypes.[2]
E. asiaticus (named for
Asia): the referred fossils consist of seven teeth, found in the
Bissekty Formation of
Uzbekistan, (dated to about 92 million years ago) and named and described by
Lev Nesov in 1995. The holotype is CCMGE N 9/12454; the other six teeth are the paratypes. The type tooth has fourteen vertical ridges on the inner side. It is usually considered a
nomen dubium. It is much earlier than E. portucalensis, which means it could belong to a different animal. Nesov himself considered Euronychodon a pure
form taxon and suggested such deviant teeth grew accidentally, when tooth pairs happened to develop on closing jaw bone sutures with juvenile individuals.[3]
Systematics
Being a tooth-taxon, the true affinities of Euronychodon are hard to determine. The teeth are similar to the better-known Paronychodon, which may be a senior synonym. Paronychodon was originally described as similar to Zapsalis, another tooth taxon often considered synonymous with Richardoestesia (a possible
dromaeosaurid). It later had many different identifications: as a
coelurid, an
ornithomimosaur, a dromaeosaurid, an
archaeopterygid and a
troodontid — though it could also be another kind of coelurosaurian theropod. While most researchers have therefore considered such taxa as representing simply indeterminate theropod teeth, a small consensus has found them to belong to the
Deinonychosauria. One study showed that the tooth enamel is identical to that found in Byronosaurus, a troodontid.[4]
Palaeobiology
The remains indicate a small animal, estimated at around two meters (6.6 feet). The teeth indicate a carnivorous or insectivorous diet. Taveirosaurus was found at the same locality.
^Antunes, M.T. & Broin, F., 1988, "Le Crétacé terminal de Beira Litoral, Portugal: remarques stratigraphiques et écologiques, étude complémentaire de Rosasia soutoi (Chelonii, Bothremydidate)", Ciências de Terra9: 153-200
^M.T. Antunes, D. Sigogneau-Russell, 1991, "Nouvelles données sur les Dinosaures du Crétacé supérieur du Portugal", Comptes-rendus de la Académie des Sciences de Paris, Series II313: 113–119
^Nesov, L.A., 1995, "Dinozavri severnoi Yevrasii: Novye dannye o sostave kompleksov, ekologii i paleobiogeografii", Scientific Research Institute of the Earth's Crust, St. Petersburg State University, St. Petersburg, Russia: pp 156
^Hwang S.H. 2005. "Phylogenetic patterns of enamel microstructure in dinosaur teeth." Journal of Morphology, 266: 208-240
Further reading
Antunes, M.T. & Mateus, O. (2003). Dinosaurs of Portugal. C. R. Palevol2: 77-95