''Dalingheornis'' is a

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 ...

enantiornithean The Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct avialans ("birds" in the broad sense), the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and cl ...

birds which lived during the early Cretaceous period, about 122 Ma ago, and are known from a single juvenile

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 preserve ...

found in the upper part of 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 ...

at Dawangzhangzi,

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 , ...

province,

People's Republic of 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 ...

. It is the first known Mesozoic bird with heterodactyl feet specifically adapted for climbing, and was probably among the most arboreal of the enantiornithines. Unlike its relatives, it had an unusually long (17mm) skeletal tail made up of 20 vertebrae, similar to the tails of

dromaeosaurid Dromaeosauridae () is a family (biology), family of feathered coelurosaurian Theropoda, theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous period (geology), Period. The name Drom ...

s. However, this may have been a juvenile feature. The fossil was named after

Yang Liwei Yang Liwei (; born 21 June 1965) is a Chinese major general, former military pilot, and former taikonaut of the People's Liberation Army. In October 2003, Yang became the first person sent into space by the Chinese space program. This missi ...

, the first Chinese astronaut in space.

Description

Some sources have doubted the presence of heterodactyl feet in this genus. Lockley ''et al''. (2007) found that its metatarsal II was not strongly curved inwards compared to other enantiornitheans, and they also noted that the supposed reversed second toe claw probably acquired that position after the animal died. In 2009,

Jingmai O'Connor Jingmai Kathleen O'Connor ( ''Zōu Jīngméi''; born August 26, 1983) is a paleontologist who works as a curator at the Field Museum in Chicago, Illinois. Biography O'Connor is from Pasadena, California. Her mother is a geologist. O'Connor says ...

considered ''Dalingheornis'' to be a nomen dubium due to its remains being stored in a private collection. However, this proposal has been criticized by Mickey Mortimer, as ''Dalingheornis'' is a valid genus under

ICZN The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its formal author, t ...

guidelines despite its inaccessibility to paleontologists.

References

Enantiornithes Prehistoric bird genera Aptian life Early Cretaceous birds of Asia Cretaceous China Fossils of China Yixian fauna Fossil taxa described in 2006 Taxa named by Luis M. Chiappe {{paleo-bird-stub