''Eoazhdarcho'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

azhdarchoid Azhdarchoidea (or azhdarchoids) is a group of pterosaurs within the suborder Pterodactyloidea, more specifically within the group Ornithocheiroidea. Pterosaurs belonging to this group lived throughout the Early and Late Cretaceous periods, with ...

pterodactyloid Pterodactyloidea (derived from the Greek words ''πτερόν'' (''pterón'', for usual ''ptéryx'') "wing", and ''δάκτυλος'' (''dáktylos'') "finger" meaning "winged finger", "wing-finger" or "finger-wing") is one of the two traditional ...

pterosaur Pterosaurs (; from Greek ''pteron'' and ''sauros'', meaning "wing lizard") is an extinct clade of flying reptiles in the order, Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 to ...

named in

2005 File:2005 Events Collage V2.png, From top left, clockwise: Hurricane Katrina in the Gulf of Mexico; the Funeral of Pope John Paul II is held in Vatican City; "Me at the zoo", the first video ever to be uploaded to YouTube; Eris was discovered in ...

by Chinese

paleontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

Lü Junchang Lü Junchang (; 1965 – 9 October 2018) was a Chinese palaeontologist and professor at the Institute of Geology, Chinese Academy of Geological Sciences. An expert on Mesozoic reptiles, he described and named dozens of dinosaur and pterosaur taxa ...

and

Ji Qiang Ji or JI may refer to: Names and titles * Ji (surname), the pinyin romanization of a number of distinct Chinese surnames * Ji (Korean name), a Korean surname and element in given names (including lists of people with the name) * -ji, an honorific ...

. The type and only known species is ''Eoazhdarcho liaoxiensis''. The

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

was found in the

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 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), a ...

-age

Lower Cretaceous Lower may refer to: *Lower (surname) *Lower Township, New Jersey *Lower Receiver (firearms) *Lower Wick Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is situated about five miles south west of Dursley, eight ...

Jiufotang Formation The Jiufotang Formation (Chinese: 九佛堂组, pinyin: ''jiǔfótáng zǔ'') is an Early Cretaceous geological formation in Chaoyang, Liaoning which has yielded fossils of feathered dinosaurs, primitive birds, pterosaurs, and other organisms (see ...

of Chaoyang,

Liaoning Liaoning () is a coastal province in Northeast China that is the smallest, southernmost, and most populous province in the region. With its capital at Shenyang, it is located on the northern shore of the Yellow Sea, and is the northernmost ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

Etymology

The genus name, ''Eoazhdarcho'', combines a Greek ''eos'', "dawn" with the name of the genus ''

Azhdarcho ''Azhdarcho'' is a genus of azhdarchid pterosaur from the late Cretaceous Period of the Bissekty Formation (middle Turonian stage, about 92 million years ago) of Uzbekistan, as well as the Zhirkindek Formation of Kazakhstan. It is known from ...

'', with the implication it was an early related form of the latter. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

, ''liaoxiensis'', refers to the ancient region

Liaoxi Liaoxi () was a former province in Northeast China, located in what is now part of Liaoning and Jilin provinces. It existed from 1949 to 1954, and its capital was Jinzhou Jinzhou (, ), formerly Chinchow, is a coastal prefecture-level city ...

Description

''Eoazhdarcho'' is based on

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 several ...

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 The wingspan (or just span) of a bird or an airplane is the distance from one wingtip to the other wingtip. For example, the Boeing 777–200 has a wingspan of , and a wandering albatross (''Diomedea exulans'') caught in 1965 had a wingspan of ...

of about 1.6 meters (5.2 feet).

Classification

The describers first assigned ''Eoazhdarcho'' to the

Azhdarchidae Azhdarchidae (from the Persian word , , a dragon-like creature in Persian mythology) is a family of pterosaurs known primarily from the Late Cretaceous Period, though an isolated vertebra apparently from an azhdarchid is known from the Early Cret ...

in a basal position, and compared it to ''Azhdarcho''. However, in 2006 they published a

cladistic Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...

analysis, determining that several forms, among them ''Eoazhdarcho'', were united in a natural group, a separate

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

that could be set apart from an Azhdarchidae proper. In 2008 that clade was by Lü, Unwin and colleagues named the

Chaoyangopteridae Chaoyangopteridae (or chaoyangopterids) is a family of pterosaurs within the larger group Azhdarchoidea. Chaoyangopterids lived mostly during the Early Cretaceous period, though possible members, ''Microtuban'', ''Xericeps'' and ''Argentinadraco' ...

— the sister group of the Azhdarchidae within a much larger

Azhdarchoidea Azhdarchoidea (or azhdarchoids) is a group of pterosaurs within the suborder Pterodactyloidea, more specifically within the group Ornithocheiroidea. Pterosaurs belonging to this group lived throughout the Early Cretaceous, Early and Late Cretaceo ...

— with ''Eoazhdarcho'' as one of the members.Lü, J., Unwin, D.M., Xu, L., and Zhang, X. (2008). "A new azhdarchoid pterosaur from the Lower Cretaceous of China and its implications for pterosaur phylogeny and evolution." ''Naturwissenschaften'', 95: 891–897 In 2014, a

phylogenetic analysis In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

conducted by Brian Andres and colleagues had recovered ''Eoazhdarcho'' as the

basalmost In phylogenetics, basal is the direction of the ''base'' (or root) of a rooted phylogenetic tree or cladogram. The term may be more strictly applied only to nodes adjacent to the root, or more loosely applied to nodes regarded as being close to th ...

member of the family

, sister taxon to the subfamily Chaoyangopterinae. The

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...

of their analysis is presented on the left. Later, in 2018, a

conducted by paleontologist Nicholas Longrich and colleagues had recovered ''Eoazhdarcho'' in a different position within the

Neoazhdarchia Azhdarchoidea (or azhdarchoids) is a group of pterosaurs within the suborder Pterodactyloidea, more specifically within the group Ornithocheiroidea. Pterosaurs belonging to this group lived throughout the Early and Late Cretaceous periods, with ...

, as a basal member of the clade Neopterodactyloidea. The cladogram of their analysis is presented on the right: Topology 1: Andres ''et al.'' (2014). Topology 2: Longrich ''et al.'' (2018).

References

External links

''Eoazhdarcho''
in The Pterosauria {{Portal bar, Paleontology, Cretaceous, China Early Cretaceous pterosaurs of Asia ? Fossil taxa described in 2005 Taxa named by Lü Junchang

Etymology

Description

Classification

See also

References

External links