''Palaeopteryx'' (meaning "ancient wing") 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 ...

of dubious

paravian Paraves are a widespread group of theropod dinosaurs that originated in the Middle Jurassic period. In addition to the extinct dromaeosaurids, troodontids, anchiornithids, and possibly the scansoriopterygids, the group also contains the av ...

theropod Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') "foot" is one of the three major groups (clades) of dinosaurs, alongside Ornithischia and Sauropodom ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

from the

Morrison Formation The Morrison Formation is a distinctive sequence of Upper Jurassic sedimentary rock found in the western United States which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltston ...

Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...

. The type species is ''P. thomsoni''.

Discovery and naming

The holotype, BYU 2022, was collected sometime between 1972 and 1976 by a paleontological expedition from

Brigham Young University Brigham Young University (BYU) is a Private education, private research university in Provo, Utah, United States. It was founded in 1875 by religious leader Brigham Young and is the flagship university of the Church Educational System sponsore ...

directed by James A. Jensen in the "Dry Mesa" quarry on the Uncompahgre Upwarp in western

(Brushy Basin Member,

). It was found among mixed fossil remains that included

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 ...

and dinosaur material. ''Palaeopteryx thomsoni'' was named by Jensen (1981), then re-described by Jensen and Padian (1989). At that time the binomial ''Palaeopteryx thomsoni'' was deemed invalid by Jensen. One notable specimen found alongside the holotype of ''Palaeopteryx'' is the right femur of a derived

maniraptora Maniraptora is a clade of coelurosaurian dinosaurs which includes the birds and the non-avian dinosaurs that were more closely related to them than to ''Ornithomimus velox''. It contains the major subgroups Avialae, Dromaeosauridae, Troodontidae, ...

n theropod (BYU 2023). BYU 2023 is missing the distal end and is about long. It is probably too small to be from the same individual as BYU 2022. BYU 2023 shows

apomorphies In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to hav ...

known only in advanced maniraptorans, including '' Microvenator'', ''

Microraptor ''Microraptor'' (Greek language, Greek, μικρός, ''mīkros'': "small"; Latin language, Latin, ''raptor'': "one who seizes") is a genus of small, four-winged dromaeosaurid dinosaurs. Numerous well-preserved fossil specimens have been recovere ...

'', and ''Archaeopteryx''.

Description

The holotype bone is about long. It was described by Jensen (1981) as an "avian – like"

proximal Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

left

tibiotarsus The tibiotarsus is the large bone between the femur and the tarsometatarsus in the leg of a bird. It is the fusion of the proximal part of the tarsus with the tibia. A similar structure also occurred in the Mesozoic Heterodontosauridae. These ...

. It was then listed by Molnar (1985) in a survey of the earliest known birds. Jensen and Padian (1989) reidentified it as the

distal Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provi ...

right

radius In classical geometry, a radius (: radii or radiuses) of a circle or sphere is any of the line segments from its Centre (geometry), center to its perimeter, and in more modern usage, it is also their length. The radius of a regular polygon is th ...

of "a small

deinonychosaur Deinonychosauria is a clade of paravian dinosaurs which lived from the Late Jurassic to the Late Cretaceous periods. Fossils have been found across the globe in North America, Europe, Africa, Asia, South America, and Antarctica,Case, J.A., Marti ...

or bird".

Classification

''Palaeopteryx'' has been the subject of much confusion on the internet, in the popular scientific press, and among

creationist Creationism is the religious belief that nature, and aspects such as the universe, Earth, life, and humans, originated with supernatural acts of divine creation, and is often pseudoscientific. Gunn 2004, p. 9, "The ''Concise Oxford Dictionary' ...

writers. It has been described as a possible bird older than ''

Archaeopteryx ''Archaeopteryx'' (; ), sometimes referred to by its German name, "" ( ''Primeval Bird'') is a genus of bird-like dinosaurs. The name derives from the ancient Greek (''archaîos''), meaning "ancient", and (''ptéryx''), meaning "feather" ...

'', but it cannot be clearly assigned to

Avialae Avialae ("bird wings") is a clade containing the only living dinosaurs, the birds, and their closest relatives. It is usually defined as all theropod dinosaurs more closely related to birds (Aves) than to Deinonychosauria, deinonychosaurs, though ...

, and its

horizon The horizon is the apparent curve that separates the surface of a celestial body from its sky when viewed from the perspective of an observer on or near the surface of the relevant body. This curve divides all viewing directions based on whethe ...

is younger than that of ''Archaeopteryx'', though it is still from the

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

. ''Palaeopteryx'' is currently classified as a member of the

Paraves Paraves are a widespread group of theropod dinosaurs that originated in the Middle Jurassic period. In addition to the extinct dromaeosauridae, dromaeosaurids, troodontidae, troodontids, Anchiornithidae, anchiornithids, and possibly the scansor ...

, within

Theropoda Theropoda (; from ancient Greek iktionary:θηρίον, , (''therion'') "wild beast"; wiktionary:πούς, , wiktionary:ποδός, (''pous, podos'') "foot" is one of the three major groups (Clade, clades) of Dinosaur, dinosaurs, alon ...

References

{{Taxonbar, from=Q2027026 Paraves Dinosaur genera Tithonian dinosaurs Morrison Formation Taxa named by James A. Jensen Fossil taxa described in 1981 Dinosaurs of the United States