''Yangavis'' is a basal pygostylian

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 ...

, belonging to the

Confuciusornithidae Confuciusornithidae is an extinct family of pygostylian avialans known from the Early Cretaceous, found in northern China. They are commonly placed as a sister group to Ornithothoraces, a group that contains all extant birds along with their close ...

, that in the

Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pro ...

lived in the area of present

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 ...

. 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 specimen ...

is ''Yangavis confucii''.

Discovery and naming

At Sihedang, in

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 ...

, a fossil avialan skeleton was excavated. In 2018, the type species ''Yangavis confucii'' was named and described by Wang Min and

Zhou Zhonghe Zhou Zhonghe (; born 19 January 1965 in Jiangdu, Jiangsu province) is a Chinese palaeontologist. He described the ancient bird ''Confuciusornis''.. Zhou graduated from Nanjing University and earned a Ph.D. in Biology in 1999 from the University o ...

. The generic name honours the Chinese paleontologist

Yang Zhongjian Yang Zhongjian, also Yang Chung-chien (; 1 June 1897 – 15 January 1979), courtesy name Keqiang (), also known as C.C. (Chung Chien) Young, was a Chinese paleontologist and zoologist. He was one of China's foremost vertebrate paleontologists. H ...

on the occasion of his 121st birthday, connecting his name with a

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

''avis'', "bird". The specific name honours

Confucius Confucius ( ; zh, s=, p=Kǒng Fūzǐ, "Master Kǒng"; or commonly zh, s=, p=Kǒngzǐ, labels=no; – ) was a Chinese philosopher and politician of the Spring and Autumn period who is traditionally considered the paragon of Chinese sages. C ...

, at the same time referring to the Confuciusornithidae. 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 several ...

, IVPP V18929, was found in a layer of the

Yixian Formation The Yixian Formation (; formerly transcribed as Yihsien Formation) is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans the late Barremian and early Aptian stages of the Early Cretaceous. It is known for its ex ...

dating from 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 ...

. It consists of an almost complete articulated skeleton, compressed on a single plate.

Description

''Yangavis'' has a wingspan of about half a metre. It differs from all other known Confuciusornithidae in several

autapomorphies In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to t ...

. The dorsal branch of the

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...

is rectangular and has a ridge on the outer side obliquely running from the lower front to the upper rear. The claw of the second finger is not strongly reduced. The claw of the first toe is as large as the second and fourth claws, instead of being the smallest. The third toe is longer than the

tarsometatarsus The tarsometatarsus is a bone that is only found in the lower leg of birds and some non-avian dinosaurs. It is formed from the fusion of several bones found in other types of animals, and homologous to the mammalian tarsus (ankle bones) and meta ...

Phylogeny

''Yangavis'' was placed in the Confuciusornithidae, above the more basal ''

Eoconfuciusornis ''Eoconfuciusornis'' a genus of extinct avialan that lived 131 Ma ago, in the Early Cretaceous of China. The type species of ''Eoconfuciusornis'', ''Eoconfuciusornis zhengi'', was named and described by Zhang Fucheng, Zhou Zhonghe and Michae ...

'' and below the more derived ''

Changchengornis ''Changchengornis'' is an extinct basal pygostylian genus from the Early Cretaceous. Its remains have been found in the People's Republic of China, in Chaomidianzi Formation rocks from around the Barremian-Aptian boundary, deposited 125 millio ...

'' in the evolutionary tree. If so, it secondarily lost the trait of a reduced second hand claw, the ecological function of which is unknown.

Notes

{{Taxonbar, from=Q55979354 Yixian fauna Confuciusornithids Fossil taxa described in 2018