''Dalingheornis'' 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 ...

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 cla ...

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 preserved ...

found in the upper part 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 ...

at Dawangzhangzi,

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 ...

province,

People's Republic of 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 ...

. 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 of feathered theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from Greek ('), meaning ...

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

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

, 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 (; born August 26, 1983) is a paleontologist who works as a curator at the Field Museum. Biography O'Connor is from Pasadena, California. Her mother is a geologist. O'Connor says that while she was not a dinosaur enthu ...

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 publisher, the I ...

guidelines despite its inaccessibility to paleontologists.

References

Enantiornitheans Prehistoric bird genera Aptian life Early Cretaceous birds of Asia Cretaceous China Fossils of China Yixian fauna Fossil taxa described in 2006 {{paleo-bird-stub