''Eosipterus'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

ctenochasmatid Ctenochasmatidae is a group of pterosaurs within the suborder Pterodactyloidea. They are characterized by their distinctive teeth, which are thought to have been used for filter-feeding. Ctenochasmatids lived from the Late Jurassic to the Early ...

pterosaur Pterosaurs are 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 million to 66 million years ago). Pterosaurs are the earli ...

from the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

period of

Liaoning ) , image_skyline = , image_alt = , image_caption = Clockwise: Mukden Palace in Shenyang, Xinghai Square in Dalian, Dalian coast, Yalu River at Dandong , image_map = Liaoning in China (+all claims hatched).svg , ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

. Fossil remains of ''Eosipterus'' dated back to the

Aptian The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), S ...

stage of the Early Cretaceous, 125 million years ago.

History and etymology

The genus was named in 1997 by Ji Shu'an and Ji Qiang. The

type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

is ''Eosipterus yangi''. The genus name is derived from Greek ''eos'', "dawn" and Greek ''pteron'', "wing" with a Latin ending; and a grammar error: normally the combination would have resulted in "eopterus". The "dawn" element refers to its age but also to China being "in the east". 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 ...

honours paleontologist Yang Daihuan. The genus is based on the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

specimen, GMV2117, found near Jinggangshan in western Liaoning Province, in the

Yixian Formation The Yixian Formation (; formerly Romanization of Chinese, transcribed as Yihsien Formation or Yixiang Formation) is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans the Barremian stage of the Early Cretaceous. I ...

. It was the first pterosaur discovered in that region. It consists of a partial crushed skeleton of a subadult individual on a slab, lacking skull and neck. Most vertebrae have been severely damaged and even their number cannot be determined. The authors state that eighteen detached belly ribs are present in the matrix.

Description

Postcranial skeleton

The wings are robust and elongated. The wing finger has the standard four phalanges, a difference from the possibly related ''

Beipiaopterus ''Beipiaopterus'' is a genus of ctenochasmatid pterosaur from the Early Cretaceous period (Aptian stage) of what is now the Yixian Formation of the China. The genus was named in 2003 by Lü Junchang. The generic name is derived from Beipiao Cit ...

'' which has lost the fourth phalanx. Total wingspan was about . The pelvis is not well preserved. The femur has a length of ; the tibia of . The fibula is strongly reduced. The foot claws are slightly curved; the fifth toe has been reduced to a single claw.

Classification

The authors placed ''Eosipterus'' in a general

Pterodactyloidea Pterodactyloidea ( ; derived from the Greek words ''πτερόν'' (''pterón'', for usual ''ptéryx'') "wing", and ''δάκτυλος'' (''dáktylos'') "finger") is one of the two traditional suborders of pterosaurs ("wing lizards"), and contai ...

incertae sedis or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...

''; in 1999 a placement within

Pterodactylidae Pterodactylidae is a controversial group of pterosaurs. During the 2000s and 2010s, several competing definitions for the various Jurassic pterodactyloid groups were proposed. Pereda-Suberbiola ''et al.'' (2012) used Fabien Knoll's (2000) defini ...

was suggested, and even a synonymy with ''

Pterodactylus ''Pterodactylus'' (from ) is a genus of extinct pterosaurs. It is thought to contain only a single species, ''Pterodactylus antiquus'', which was the first pterosaur to be named and identified as a flying reptile and one of the first prehis ...

'' was proposed within a hypothesis that the lower Yixian Formation dated from the

Late Jurassic The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...

. A

cladistic Cladistics ( ; from Ancient Greek 'branch') 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 ...

study in 2006 found that it was a member of the

Ctenochasmatidae Ctenochasmatidae is a group of pterosaurs within the suborder Pterodactyloidea. They are characterized by their distinctive teeth, which are thought to have been used for filter-feeding. Ctenochasmatids lived from the Late Jurassic to the Earl ...

—

David Unwin David (; , "beloved one") was a king of ancient Israel and Judah and the third king of the United Monarchy, according to the Hebrew Bible and Old Testament. The Tel Dan stele, an Aramaic-inscribed stone erected by a king of Aram-Damas ...

more precisely assigned it to the Ctenochasmatinae. Below is

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

following a topology by Andres, Clark and Xu (2014). In the analysis, they recovered ''Eosipterus'' within the family Ctenochasmatidae, more precisely within the tribe Pterodaustrini, placed in a more derived position than ''

Pterodaustro ''Pterodaustro'' (from Greek language, Greek , and Latin , ) is a genus of ctenochasmatid Pterodactyloidea, pterodactyloid pterosaur from South America. Its fossil remains dated back to the Early Cretaceous period, about 105 million years ago. ...

''.

References

*Ji, S. & Ji Q., 1997, "Discovery of a new pterosaur in western Liaoning, China", ''Acta Geologica Sinica'', 71(2) pp. 115–121 *Ji, S. A., Ji, Q., and Padian, K., 1999, "Biostratigraphy of new pterosaurs from China", ''Nature'', 398: 573 *Lü Junchang, Gao Chunling, Meng Qingjin, Liu Jinyuan, Ji Qiang, 2006, "On the Systematic Position of ''Eosipterus yangi'' Ji et Ji, 1997 among Pterodactyloids", ''Acta Geologica Sinica'' 80(5) *Wang Xiaolin, Kellner, A. W. A., Zhou Zhonghe, and Campos, D. A., 2007, "A new pterosaur (Ctenochasmatidae, Archaeopterodactyloidea) from the Lower Cretaceous Yixian Formation of China", ''Cretaceous Research'', 28: 245–260 *

External links