Euornithes (from

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

' meaning "true birds") is a natural group which includes the most recent common ancestor of all

avialan Avialae ("bird wings") is a clade containing the only living dinosaurs, the birds. It is usually defined as all theropod dinosaurs more closely related to birds (Aves) than to deinonychosaurs, though alternative definitions are occasionally used ...

s closer to modern

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

s than to ''

Sinornis ''Sinornis'' is a genus of enantiornithean birds from the Lower Cretaceous Jiufotang Formation of the People's Republic of China. When it was described in 1992, this 120 million-year-old sparrow-sized skeleton represented a new avian sharing "pr ...

''.

Description

Clarke ''et al''. (2006) found that the most primitive known euornithians (the

Yanornithiformes Yanornithiformes is an order of ornithuromorph birds from the early Cretaceous Period of China. All known specimens come from the Yixian Formation and Jiufotang Formation, dating to the early Aptian age, 124.6 to 120 million years ago. The fami ...

) had a mosaic of advanced and primitive features. These species retained primitive features like

gastralia Gastralia (singular gastralium) are dermal bones found in the ventral body wall of modern crocodilians and tuatara, and many prehistoric tetrapods. They are found between the sternum and pelvis, and do not articulate with the vertebrae. In these ...

and a

pubic symphysis The pubic symphysis is a secondary cartilaginous joint between the left and right superior rami of the pubis of the hip bones. It is in front of and below the urinary bladder. In males, the suspensory ligament of the penis attaches to the pubic ...

. They also showed the first fully modern

pygostyle Pygostyle describes a skeletal condition in which the final few caudal vertebrae are fused into a single ossification, supporting the tail feathers and musculature. In modern birds, the rectrices attach to these. The pygostyle is the main compone ...

s, and the type specimen of ''

Yixianornis ''Yixianornis'' (meaning "Yixian Formation bird") is a bird genus from the early Cretaceous period. Its remains have been found in the Jiufotang Formation at Chaoyang (People's Republic of China) dated to the early Aptian age, around 120 millio ...

'' (IVPP 13631) preserves eight elongated

rectrices Flight feathers (''Pennae volatus'') are the long, stiff, asymmetrically shaped, but symmetrically paired pennaceous feathers on the wings or tail of a bird; those on the wings are called remiges (), singular remex (), while those on the tail ...

(tail feathers) in a modern arrangement. No earlier

pygostylia Pygostylia is a group of avialans which includes the Confuciusornithidae and all of the more advanced species, the Ornithothoraces. Definition The group Pygostylia was intended to encompass all avialans with a short, stubby tail, as opposed to ...

ns are known which preserve a fan of tail feathers of this sort; instead, they showed only paired plumes or a tuft of short feathers.

Classification

The name Euornithes has been used for a wide variety of avialan groups since it was first named by

Edward Drinker Cope Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontologist, comparative anatomist, herpetologist, and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested ...

in 1889. It was first defined as a

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, ...

in 1998 by

Paul Sereno Paul Callistus Sereno (born October 11, 1957) is a professor of paleontology at the University of Chicago and a National Geographic "explorer-in-residence" who has discovered several new dinosaur species on several continents, including at sites ...

, who made it the group of all animals closer to birds than to

Enantiornithes 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 ...

(represented by ''Sinornis''). This definition currently includes similar content as another widely used name, Ornithuromorpha, named and defined by

Luis Chiappe Luis María Chiappe (born 18 June 1962) is an Argentine paleontologist born in Buenos Aires who is best known for his discovery of the first sauropod nesting sites in the badlands of Patagonia in 1997 and for his work on the origin and early evo ...

in 1999 as the common ancestor of '' Patagopteryx'', ''

Vorona ''Vorona'' ( ; Malagasy for "bird", ''V. berivotrensis'', "from Berivotra") is a monotypic genus of prehistoric birds. It was described from fossils found in a Maevarano Formation quarry near the village of Berivotra, Mahajanga Province, Madag ...

'', and Ornithurae, plus all of its descendants. Because one definition is node-based and the other branch-based, Ornithuromorpha is a slightly less inclusive group.

Relationships

The cladogram below follows the results of a phylogenetic analysis by Lee ''et al.'', 2014:

Other genera

The following is a list of primitive euornithian genera and those that cannot be confidently referred to any subgroups, following Holtz (2011) unless otherwise noted.Holtz, Thomas R. Jr. (2012) ''Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages,'
Winter 2011 Appendix.
/ref> *†'' Alamitornis'' *†'' Changmaornis'' *†''

Changzuiornis ''Changzuiornis'' is an extinct genus of ornithuromorph bird from the Early Cretaceous of present-day China. It contains a single species, ''C. ahgmi''. Discovery and naming At Sihedang near Lingyuan in Liaoning, a bird skeleton was excav ...

''Huang, J., Wang, X., Hu, Y., Liu, J., Peteya, J. A., & Clarke, J. A. (2016). A new ornithurine from the Early Cretaceous of China sheds light on the evolution of early ecological and cranial diversity in birds. ''PeerJ'', 4: e1765. *†''

Dingavis ''Dingavis'' is an extinct genus of ornithuromorph bird from the Early Cretaceous of present-day China. It contains a single species, ''D. longimaxilla''. Discovery and naming At Sihedang in Liaoning a fossil bird skeleton was excavated. Ca ...

'' *†''

Gargantuavis ''Gargantuavis'' is an extinct genus of large, primitive bird containing the single species ''Gargantuavis philoinos''. It is the only member of the monotypic family Gargantuaviidae. Its fossils were discovered in several formations dating to 73 ...

'' *†'' Horezmavis'' *†'' Iteravis'' *†''

Juehuaornis ''Juehuaornis'' is an extinct genus of ornithuromorph bird from the Early Cretaceous of present-day China. It contains a single species, ''J. zhangi''. Discovery and naming The holotype, SJG 00001, was found near Lingyuan in a layer of the J ...

'' *†'' Platanavis'' *†'' Wyleyia''? *†'' Yumenornis'' *'' Xinghaiornis'' *†'' Zhyraornis'' Note that Holtz also included the genera '' Eurolimnornis'' and '' Piksi'' as euornitheans, though they have since been re-identified as

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 ...

References

External links

{{Taxonbar, from=Q2752642 Evolution of birds Extant Early Cretaceous first appearances Taxa named by Edward Drinker Cope