Elmisaurinae
Encyclopedia
Elmisaurinae is a subfamily of bird-like maniraptora
n theropod dinosaur
s within the clade Oviraptorosauria
or Oviraptoridae
. While more advanced than earlier oviraptorosaurs like Caudipteryx
, elmisaurines were fairly primitive compared with their close relatives the oviraptorines
, though this by no means reduces the distinct variation and unique nature of the group. Whereas oviraptorines had highly shortened snouts, elmisaurine jaws were long and shallow with an elongated dentary and extended symphysis. Indeed, the jaw of an elmisaurine is its most distinctive feature, historically, whose surface and internal structure is distinct from that of other dinosaurs, including oviraptorines. Elmisaurines are best known for their cranial anatomy, but the earliest forms are known from their postcrania alone, and include such novel features as a fused ankle (as also seen in similar and possibly related Avimimus portentosus
), an extremely short tail, possibly with a pygostyle
as in Nomingia gobiensis
, and with exceptionally slender and long legs, giving them a gracile, long-legged appearance that may have resembled some of the smaller ratite birds, such as the emu
.
, comprises the family Oviraptoridae
. The group has a confusing history of classification. It was traditionally seen as being more primitive than the oviraptorines, and thus placed as a distinct family, called the Caenagnathidae. However, that name is anchored on the species Caenagnathus collinsi, now recognized as a more primitive species, while the rest of the supposed group were found in later analyses to be nested within the traditional oviraptorids.
While in the past twenty years, only about two to six species were commonly recognized as belonging to the Elmisaurinae, currently that number may be much greater, with new discoveries and theories about older species that may inflate this number to up to ten. Much of this historical difference centers on the first elmisaurine to be described, Chirostenotes pergracilis. Due to the poor preservation of most elmisaurine remains and resulting misidentifications, different bones and different specimens of Chirostenotes have historically been assigned to a number of different species. For example, the feet of one species, named Macrophalangia canadensis, were known from the same region from which Chirostenotes pergracilis was recovered, but the discovery of a new specimen with both hands and feet preserved provided the support to combine them, while the later discovery of a partial skull with hands and feet.
to be a junior synonym of Chirostenotes sternbergi
, as they both occur in the same North American locality, far from the Asian species Elmisaurus rarus
. The genus Caenagnathasia martinsoni
was originally placed in this family, but it is probably more primitive, lying outside Oviraptoridae within the superfamily Caenagnathoidea. Additionally, Maryańska, Osmólska, and Wołsan considered the oviraptorosaur with a pygostyle
, Nomingia gobiensis
, a member of this family, and Longrich and colleagues (2010) found the giant Gigantoraptor
as a member.
Elmisaurinae includes -
Maniraptora
Maniraptora is a clade of coelurosaurian dinosaurs which includes the birds and the dinosaurs that were more closely related to them than to Ornithomimus velox. It contains the major subgroups Avialae, Deinonychosauria, Oviraptorosauria and Therizinosauria. Ornitholestes and the Alvarezsauroidea...
n theropod dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
s within the clade Oviraptorosauria
Oviraptorosauria
Oviraptorosaurs are a group of feathered maniraptoran dinosaurs from the Cretaceous Period of what are now Asia and North America. They are distinct for their characteristically short, beaked, parrot - like skulls, with or without bony crests atop the head...
or Oviraptoridae
Oviraptoridae
Oviraptoridae is a group of bird-like, herbivorous and omnivorous maniraptoran dinosaurs. Oviraptorids are characterized by their toothless, parrot-like beaks and, in some cases, elaborate crests. They were generally small, measuring between one and two metres long in most cases, though some...
. While more advanced than earlier oviraptorosaurs like Caudipteryx
Caudipteryx
Caudipteryx is a genus of peacock-sized theropod dinosaurs that lived in the Aptian age of the early Cretaceous Period . They were feathered and remarkably birdlike in their overall appearance....
, elmisaurines were fairly primitive compared with their close relatives the oviraptorines
Oviraptorinae
Oviraptorinae is a subfamily of bird-like maniraptoran theropod dinosaurs within the clade Oviraptoridae.-Classification and species: The classification of the oviraptorids has been controversial...
, though this by no means reduces the distinct variation and unique nature of the group. Whereas oviraptorines had highly shortened snouts, elmisaurine jaws were long and shallow with an elongated dentary and extended symphysis. Indeed, the jaw of an elmisaurine is its most distinctive feature, historically, whose surface and internal structure is distinct from that of other dinosaurs, including oviraptorines. Elmisaurines are best known for their cranial anatomy, but the earliest forms are known from their postcrania alone, and include such novel features as a fused ankle (as also seen in similar and possibly related Avimimus portentosus
Avimimus
Avimimus , meaning "bird mimic" , was a genus of bird-like maniraptoran dinosaur that lived in the late Cretaceous in what is now Mongolia, around 70 million years ago.-Description:...
), an extremely short tail, possibly with a pygostyle
Pygostyle
Pygostyle refers to a number of the final few caudal vertebrae fused into a single ossification, supporting the tail feathers and musculature. In modern birds, the rectrices attach to these....
as in Nomingia gobiensis
Nomingia
Nomingia is a genus of oviraptorid theropod dinosaur hailing from the Late Cretaceous Bugin Tsav Beds of Mongolia.-Discovery and naming:...
, and with exceptionally slender and long legs, giving them a gracile, long-legged appearance that may have resembled some of the smaller ratite birds, such as the emu
Emu
The Emu Dromaius novaehollandiae) is the largest bird native to Australia and the only extant member of the genus Dromaius. It is the second-largest extant bird in the world by height, after its ratite relative, the ostrich. There are three subspecies of Emus in Australia...
.
Classification
The clade Elmisaurinae, together with its sister group the OviraptorinaeOviraptorinae
Oviraptorinae is a subfamily of bird-like maniraptoran theropod dinosaurs within the clade Oviraptoridae.-Classification and species: The classification of the oviraptorids has been controversial...
, comprises the family Oviraptoridae
Oviraptoridae
Oviraptoridae is a group of bird-like, herbivorous and omnivorous maniraptoran dinosaurs. Oviraptorids are characterized by their toothless, parrot-like beaks and, in some cases, elaborate crests. They were generally small, measuring between one and two metres long in most cases, though some...
. The group has a confusing history of classification. It was traditionally seen as being more primitive than the oviraptorines, and thus placed as a distinct family, called the Caenagnathidae. However, that name is anchored on the species Caenagnathus collinsi, now recognized as a more primitive species, while the rest of the supposed group were found in later analyses to be nested within the traditional oviraptorids.
While in the past twenty years, only about two to six species were commonly recognized as belonging to the Elmisaurinae, currently that number may be much greater, with new discoveries and theories about older species that may inflate this number to up to ten. Much of this historical difference centers on the first elmisaurine to be described, Chirostenotes pergracilis. Due to the poor preservation of most elmisaurine remains and resulting misidentifications, different bones and different specimens of Chirostenotes have historically been assigned to a number of different species. For example, the feet of one species, named Macrophalangia canadensis, were known from the same region from which Chirostenotes pergracilis was recovered, but the discovery of a new specimen with both hands and feet preserved provided the support to combine them, while the later discovery of a partial skull with hands and feet.
Species
Today, Elmisaurinae usually contains six species in three genera. However, a few paleontologists consider Elmisaurus elegansElmisaurus
Elmisaurus is an extinct genus of dinosaur from the Late Cretaceous. It was a theropod belonging to the Oviraptorosauria. Its fossils have been found in Asia and North America. It is known from only its feet and hands....
to be a junior synonym of Chirostenotes sternbergi
Chirostenotes
Chirostenotes is a genus of oviraptorosaurian dinosaur from the late Cretaceous of Alberta, Canada. The type species is Chirostenotes pergracilis. Some researchers recognize a second species, C...
, as they both occur in the same North American locality, far from the Asian species Elmisaurus rarus
Elmisaurus
Elmisaurus is an extinct genus of dinosaur from the Late Cretaceous. It was a theropod belonging to the Oviraptorosauria. Its fossils have been found in Asia and North America. It is known from only its feet and hands....
. The genus Caenagnathasia martinsoni
Caenagnathasia
Caenagnathasia is a small oviraptorosaurian theropod dinosaur from the Late Cretaceous of Uzbekistan.The type species Caenagnathasia martinsoni was named and described in 1993/1994 by Philip Currie, Stephen Godfrey and Lev Nesov...
was originally placed in this family, but it is probably more primitive, lying outside Oviraptoridae within the superfamily Caenagnathoidea. Additionally, Maryańska, Osmólska, and Wołsan considered the oviraptorosaur with a pygostyle
Pygostyle
Pygostyle refers to a number of the final few caudal vertebrae fused into a single ossification, supporting the tail feathers and musculature. In modern birds, the rectrices attach to these....
, Nomingia gobiensis
Nomingia
Nomingia is a genus of oviraptorid theropod dinosaur hailing from the Late Cretaceous Bugin Tsav Beds of Mongolia.-Discovery and naming:...
, a member of this family, and Longrich and colleagues (2010) found the giant Gigantoraptor
Gigantoraptor
Gigantoraptor is a genus of giant oviraptorosaurian theropod dinosaur that lived 70 million years ago during the late Cretaceous Period. It was discovered in 2005 in the Iren Dabasu Formation, Erlian basin, in Inner Mongolia.-Discovery and naming:...
as a member.
Elmisaurinae includes -
- Avimimus portentosus, an enigmatic species often considered a more primitive oviraptorosaur. Nemegt FormationNemegt FormationThe Nemegt Formation is a geological formation dating from the Late Cretaceous sedimentary from the Gobi Desert of Mongolia. It overlies and sometimes forms folds with the Barun Goyot Formation. It consists of river channel sediments and contains fossils of fish, turtles, crocodilians, birds and a...
, MongoliaMongoliaMongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...
. - Avimimus sp.AvimimusAvimimus , meaning "bird mimic" , was a genus of bird-like maniraptoran dinosaur that lived in the late Cretaceous in what is now Mongolia, around 70 million years ago.-Description:...
, an unnamed second species from the Iren Debasu Formation, Mongolia. - Avimimus? sp.AvimimusAvimimus , meaning "bird mimic" , was a genus of bird-like maniraptoran dinosaur that lived in the late Cretaceous in what is now Mongolia, around 70 million years ago.-Description:...
, a possible third species from the Dinosaur Park FormationDinosaur Park FormationThe Dinosaur Park Formation is the uppermost member of the Judith River Group, a major geologic unit in southern Alberta. It was laid down over a period of time between about 76.5 and 75 million years ago. The formation is made up of deposits of a high-sinuosity fluvial system, and is capped...
and Scollard FormationScollard Formation-References:* Ryan, M. J., and Russell, A. P., 2001. Dinosaurs of Alberta : In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, pp. 279-297....
, AlbertaAlbertaAlberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
. - Chirostenotes pergracilisChirostenotesChirostenotes is a genus of oviraptorosaurian dinosaur from the late Cretaceous of Alberta, Canada. The type species is Chirostenotes pergracilis. Some researchers recognize a second species, C...
, described initially from two hands and a partial lower arm. Many subsequently named species have been referred to this species, including a single foot named Macrophalangia canadensis, adding to the known fossil material. - Chirostenotes elegansChirostenotesChirostenotes is a genus of oviraptorosaurian dinosaur from the late Cretaceous of Alberta, Canada. The type species is Chirostenotes pergracilis. Some researchers recognize a second species, C...
, a smaller, more gracile Canadian species originally described as a species of OrnithomimusOrnithomimusOrnithomimus is a genus of ornithomimid dinosaur from the Late Cretaceous Period of what is now North America.In 1890 Ornithomimus velox was named by Othniel Charles Marsh on the basis of a foot and partial hand from the Maastrichtian Denver Formation. Another seventeen species have been named since...
. It is probably a senior synonym of Chirostenotes sternberg Some consider it a species of Elmisaurus instead, as both are smaller and more slender than Chirostenotes pergracilis. It is also possible that this species represents a different gender of the larger C. pergracilis specimens. - Chirostenotes sp.ChirostenotesChirostenotes is a genus of oviraptorosaurian dinosaur from the late Cretaceous of Alberta, Canada. The type species is Chirostenotes pergracilis. Some researchers recognize a second species, C...
, a possible new species, has been identified from part of a lower jaw found in Montana, but not named. - Elmisaurus rarusElmisaurusElmisaurus is an extinct genus of dinosaur from the Late Cretaceous. It was a theropod belonging to the Oviraptorosauria. Its fossils have been found in Asia and North America. It is known from only its feet and hands....
, the only known Asian caenagnathid (excluding Caenagnathasia martinsoni), is known only from elements of the foot. - The "Triebold caenagnathid", a possible new species or genus collected by Triebold Paleontology of South Dakota, known from two excellently preserved partial specimens acquired by the Carnegie Museums of PittsburghCarnegie Museums of PittsburghCarnegie Museums of Pittsburgh are four museums that are operated by the Carnegie Institute headquartered in the Oakland neighborhood of Pittsburgh, Pennsylvania...
. An apparently giant species with a well preserved skull and evidence of an oviraptorid-like crest, it is currently awaiting a published description. - Hagryphus giganteusHagryphusHagryphus is an oviraptorosaurian theropod dinosaur from the Upper Cretaceous Period of what is now Utah. To date, only a single species is known, H. giganteus...
, discovered most recently, is a fairly large and over-assuming yet seldom mentioned species from Upper Cretaceous beds in Utah, USA (and is roughly the same age as Chirostenotes pergacilisChirostenotesChirostenotes is a genus of oviraptorosaurian dinosaur from the late Cretaceous of Alberta, Canada. The type species is Chirostenotes pergracilis. Some researchers recognize a second species, C...
.