''Euronychodon'' ("European claw tooth") is the name given to 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 ...

coelurosaur Coelurosauria (; from Greek, meaning "hollow tailed lizards") is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. Coelurosauria is a subgroup of theropod dinosaurs that includes compsognathids, tyran ...

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 ...

from 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 ...

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 subcontinent of Eurasia and it is located entirel ...

and

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...

. ''Euronychodon'' is known from teeth only. These are similar to those of another coelurosaur tooth genus, ''

Paronychodon ''Paronychodon'' (meaning "beside claw tooth") was a theropod dinosaur genus. It is a tooth taxon, often considered dubious because of the fragmentary nature of the fossils, which include "buckets" of teeth from many disparate times and places b ...

''.

Species

Two species of ''Euronychodon'' have been named to date. *''E. portucalensis'' (named for

Portugal Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of ...

, from ''Portucale'', an old name of

Porto Porto or Oporto () is the second-largest city in Portugal, the capital of the Porto District, and one of the Iberian Peninsula's major urban areas. Porto city proper, which is the entire municipality of Porto, is small compared to its metropol ...

): the remains consist of three teeth. In 1988 referred to ''Paronychodon lacustris'', they were later considered diagnostic enough for them to represent a distinct genus and species. They were found at the locality of

Taveiro Taveiro is a former civil parish in the municipality of Coimbra, Portugal. The population in 2011 was 1,948, in an area of 10.23 km2. On 28 January 2013 it merged with Ameal and Arzila to form Taveiro, Ameal e Arzila Taveiro, Ameal e Arzila ...

, dated as

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 ...

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 interval ...

(about 70 million years old). The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...

of ''Euronychodon'', ''E. portucalensis'' was named and described in 1991 by Miguel Telles Antunes and

Denise Sigogneau-Russell Denise Sigogneau-Russell (born ''c.'' 1941/42) is a French palaeontologist who specialises in mammals from the Mesozoic, particularly from France and the UK. She is currently based at the Muséum National d'Histoire Naturelle. Background Denise S ...

. The generic name is a contraction of "Europe" and ''Paronychodon''. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...

CEPUNL 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

paratype In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype nor a syntype). O ...

s. *''E. asiaticus'' (named for

): the referred fossils consist of seven teeth, found in the

Bissekty Formation The Bissekty Formation (sometimes referred to as Bissekt) is a geologic formation and Lagerstätte which crops out in the Kyzyl Kum desert of Uzbekistan, and dates to the Late Cretaceous Period. Laid down in the mid to late Turonian, it is dated ...

Uzbekistan Uzbekistan (, ; uz, Ozbekiston, italic=yes / , ; russian: Узбекистан), officially the Republic of Uzbekistan ( uz, Ozbekiston Respublikasi, italic=yes / ; russian: Республика Узбекистан), is a doubly landlocked co ...

, (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 Form classification is the classification of organisms based on their morphology, which does not necessarily reflect their biological relationships. Form classification, generally restricted to palaeontology, reflects uncertainty; the goal of s ...

and suggested such deviant teeth grew accidentally, when tooth pairs happened to develop on closing jaw bone sutures with juvenile individuals.

Systematics

Being a tooth-taxon, the true affinities of ''Euronychodon'' are hard to determine. The teeth are similar to the better-known ''

'', which may be a senior synonym. ''Paronychodon'' was originally described as similar to ''

Zapsalis ''Zapsalis'' is a genus of dromaeosaurine theropod dinosaurs. It is a tooth taxon, often considered dubious because of the fragmentary nature of the fossils, which include teeth but no other remains. Etymology The generic name is derived from ...

'', another tooth taxon often considered synonymous with ''

Richardoestesia ''Richardoestesia'' is a morphogenus of theropod dinosaur teeth, originally described from the Late Cretaceous of what is now North America. It currently contains two species, ''R. gilmorei'' and ''R. isosceles''. It has been used as a morphota ...

'' (a possible

dromaeosaurid Dromaeosauridae () is a family of feathered theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from Greek ('), meaning ...

). It later had many different identifications: as a

coelurid Coeluridae is a historically unnatural group of generally small, carnivorous dinosaurs from the late Jurassic Period. For many years, any small Jurassic or Cretaceous theropod that did not belong to one of the more specialized families recogniz ...

, an ornithomimosaur, a dromaeosaurid, an archaeopterygid and a

troodontid Troodontidae is a clade of bird-like theropod dinosaurs. During most of the 20th century, troodontid fossils were few and incomplete and they have therefore been allied, at various times, with many dinosaurian lineages. More recent fossil disco ...

— 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 Deinonychosauria is a clade of paravian dinosaurs which lived from the Late Jurassic to the Late Cretaceous periods. Fossils have been found across the globe in North America, Europe, Africa, Asia, South America, and Antarctica,Case, J.A., Mar ...

. One study showed that the tooth enamel is identical to that found in '' Byronosaurus'', a troodontid.Hwang S.H. 2005. "Phylogenetic patterns of enamel microstructure in dinosaur teeth." ''Journal of Morphology'', 266: 208-240

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.

Species

Systematics

Palaeobiology

See also

References

Further reading