Eoazhdarcho
Encyclopedia
Eoazhdarcho is a genus
of azhdarchoid
pterodactyloid pterosaur
named in 2005
by Chinese paleontologists Lü Junchang and Ji Qiang. The type species
is Eoazhdarcho liaoxiensis. The genus name combines a Greek eos, "dawn" with the name of the genus Azhdarcho
, with the implication it was an early related form of the latter. The specific name refers to the ancient region Liaoxi.
The fossil
was found in the Aptian
-age Lower Cretaceous Jiufotang Formation
of Chaoyang, Liaoning
, China
. The genus is based on holotype
GMN-03-11-02, a partial skeleton and lower jaw, and is distinguished from other pterosaurs by the proportions of its bones. The metacarpals are very elongated but the cervical vertebrae and hind limbs are not. It was relatively small by azhdarchoid standards, with a wingspan
of about 1.6 meters (5.2 feet).
Its describers first assigned Eoazhdarcho to the Azhdarchidae
in a basal
position, and compared it to Azhdarcho. However, in 2006 they published a cladistic
analysis, determining that several forms, among them Eoazhdarcho, were united in a natural group, a separate clade
that could be set apart from a Azhdarchidae proper. In 2008 that clade was by Lü, Unwin and colleagues named the Chaoyangopteridae
— the sister group of the Azhdarchidae within a much larger Azhdarchoidea
— with Eoazhdarcho as one of the members.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of azhdarchoid
Azhdarchoidea
Azhdarchoidea is a group of pterosaurs within the suborder Pterodactyloidea.-Classification:Listing of families and genera after Unwin 2006 except where specified.* Superfamily Azhdarchoidea** Genus "Aurorazhdarcho"** Family Chaoyangopteridae...
pterodactyloid pterosaur
Pterosaur
Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...
named in 2005
2005 in paleontology
-New taxa:-New taxa:-Xiphosurans:* Fossils of Lunataspis, the earliest known xiphosuran, are discovered in Canada. It was not given a formal description until 2008, however.-New taxa:-Newly named dinosaurs:...
by Chinese paleontologists Lü Junchang and Ji Qiang. The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
is Eoazhdarcho liaoxiensis. The genus name combines a Greek eos, "dawn" with the name of the genus Azhdarcho
Azhdarcho
Azhdarcho is a genus of pterodactyloid pterosaur from the late Cretaceous Period of the Bissekty Formation of Uzbekistan. It is known from fragmentary remains including the distinctive, elongated neck vertebrae that characterizes members of the family Azhdarchidae, which also includes such giant...
, with the implication it was an early related form of the latter. The specific name refers to the ancient region Liaoxi.
The fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
was found in the Aptian
Aptian
The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous epoch or series and encompasses the time from 125.0 ± 1.0 Ma to 112.0 ± 1.0 Ma , approximately...
-age Lower Cretaceous Jiufotang Formation
Yixian Formation
The Yixian Formation is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans 11 million years during the early Cretaceous period...
of Chaoyang, Liaoning
Liaoning
' is a province of the People's Republic of China, located in the northeast of the country. Its one-character abbreviation is "辽" , a name taken from the Liao River that flows through the province. "Níng" means "peace"...
, China
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
. The genus is based on holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
GMN-03-11-02, a partial skeleton and lower jaw, and is distinguished from other pterosaurs by the proportions of its bones. The metacarpals are very elongated but the cervical vertebrae and hind limbs are not. It was relatively small by azhdarchoid standards, with a wingspan
Wingspan
The wingspan of an airplane or a bird, is the distance from one wingtip to the other wingtip. For example, the Boeing 777 has a wingspan of about ; and a Wandering Albatross caught in 1965 had a wingspan of , the official record for a living bird.The term wingspan, more technically extent, is...
of about 1.6 meters (5.2 feet).
Its describers first assigned Eoazhdarcho to the Azhdarchidae
Azhdarchidae
Azhdarchidae is a family of pterosaurs known primarily from the late Cretaceous Period, though an isolated vertebrae apparently from an azhdarchid is known from the early Cretaceous as well...
in a basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
position, and compared it to Azhdarcho. However, in 2006 they published a cladistic
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
analysis, determining that several forms, among them Eoazhdarcho, were united in a natural group, a separate clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
that could be set apart from a Azhdarchidae proper. In 2008 that clade was by Lü, Unwin and colleagues named the Chaoyangopteridae
Chaoyangopteridae
The Chaoyangopteridae are a family of pterosaurs within the Azhdarchoidea.The clade Chaoyangopteridae was first defined in 2008 by Lü Junchang and David Unwin as: "Chaoyangopterus, Shenzhoupterus, their most recent common ancestor and all taxa more closely related to this clade than to Tapejara,...
— the sister group of the Azhdarchidae within a much larger Azhdarchoidea
Azhdarchoidea
Azhdarchoidea is a group of pterosaurs within the suborder Pterodactyloidea.-Classification:Listing of families and genera after Unwin 2006 except where specified.* Superfamily Azhdarchoidea** Genus "Aurorazhdarcho"** Family Chaoyangopteridae...
— with Eoazhdarcho as one of the members.
External links
- Eoazhdarcho in The Pterosauria