Palaeopteryx
Encyclopedia
Palaeopteryx is a genus
of theropod dinosaur
now considered a nomen dubium
. It was named and misidentified by J. A. Jensen
in 1981, then redescribed by Jensen and K. Padian in 1989. At that time the binomial Palaeopteryx thomsoni was deemed invalid by Jensen. The only referred specimen is a single bone fragment (BYU
2022).
Palaeopteryx (BYU 2022) has been the subject of much confusion on the internet, in the popular scientific press, and among creationist writers. It has been described as a possible bird older than Archaeopteryx
, but it cannot be clearly assigned to Avialae
, and its horizon
is younger than that of Archaeopteryx, though it is still from the Jurassic
.
BYU 2022 is about 45 millimeters long. It was described by Jensen in 1981 as an "avian – like" proximal
left tibiotarsus
. It was then listed by R. E. Molnar in 1985 in a survey of the earliest known birds. Jensen and Padian reidentified it as the distal
right radius
of "a small deinonychosaur or bird" in 1989.
BYU 2022 was collected in the 1970s by paleontological expeditions from Brigham Young University
directed by J. A. Jensen. It was found in Late Jurassic
deposits in the "Dry Mesa" quarry on the Uncompahgre Upwarp in western Colorado
(Brushy Basin Member, Morrison Formation
). It was found among mixed fossil remains that included pterosaur
and dinosaur material. One notable specimen found with it is the right femur of a derived maniraptora
n theropod (BYU 2023). BYU 2023 is missing the distal end and is about 63 mm long. It is probably too small to be from the same individual as BYU 2022. BYU 2023 shows apomorphies known only in advanced maniraptorans, including Microvenator
, Microraptor
, and Archaeopteryx.
BYU 2022 and 2023 are important because they are samples of small – bodied maniraptorans from Jurassic North America.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of theropod dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
now considered a nomen dubium
Nomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
. It was named and misidentified by J. A. Jensen
James A. Jensen
James A. Jensen , was an American paleontologist. His extensive collecting program at BYU in the Utah-Colorado region which spanned 23 years was comparable in terms of the number of specimens collected to that of Barnum Brown during the early 20th century. He was given the name "Dinosaur Jim"...
in 1981, then redescribed by Jensen and K. Padian in 1989. At that time the binomial Palaeopteryx thomsoni was deemed invalid by Jensen. The only referred specimen is a single bone fragment (BYU
Brigham Young University
Brigham Young University is a private university located in Provo, Utah. It is owned and operated by The Church of Jesus Christ of Latter-day Saints , and is the United States' largest religious university and third-largest private university.Approximately 98% of the university's 34,000 students...
2022).
Palaeopteryx (BYU 2022) has been the subject of much confusion on the internet, in the popular scientific press, and among creationist writers. It has been described as a possible bird older than Archaeopteryx
Archaeopteryx
Archaeopteryx , sometimes referred to by its German name Urvogel , is a genus of theropod dinosaur that is closely related to birds. The name derives from the Ancient Greek meaning "ancient", and , meaning "feather" or "wing"...
, but it cannot be clearly assigned to Avialae
Avialae
Avialae is a clade of dinosaurs containing their only living representatives, birds , and the most immediate extinct relatives of birds.-Competing definitions:...
, and its horizon
Stratum
In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers...
is younger than that of Archaeopteryx, though it is still from the Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
.
BYU 2022 is about 45 millimeters long. It was described by Jensen in 1981 as an "avian – like" proximal
Anatomical terms of location
Standard anatomical terms of location are designations employed in science that deal with the anatomy of animals to avoid ambiguities that might otherwise arise. They are not language-specific, and thus require no translation...
left tibiotarsus
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...
. It was then listed by R. E. Molnar in 1985 in a survey of the earliest known birds. Jensen and Padian reidentified it as the distal
Anatomical terms of location
Standard anatomical terms of location are designations employed in science that deal with the anatomy of animals to avoid ambiguities that might otherwise arise. They are not language-specific, and thus require no translation...
right radius
Radius
In classical geometry, a radius of a circle or sphere is any line segment from its center to its perimeter. By extension, the radius of a circle or sphere is the length of any such segment, which is half the diameter. If the object does not have an obvious center, the term may refer to its...
of "a small deinonychosaur or bird" in 1989.
BYU 2022 was collected in the 1970s by paleontological expeditions from Brigham Young University
Brigham Young University
Brigham Young University is a private university located in Provo, Utah. It is owned and operated by The Church of Jesus Christ of Latter-day Saints , and is the United States' largest religious university and third-largest private university.Approximately 98% of the university's 34,000 students...
directed by J. A. Jensen. It was found in Late Jurassic
Late Jurassic
The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.2 ± 4.0 to 145.5 ± 4.0 million years ago , which is preserved in Upper Jurassic strata. In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age...
deposits in the "Dry Mesa" quarry on the Uncompahgre Upwarp in western Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
(Brushy Basin Member, Morrison Formation
Morrison Formation
The Morrison Formation is a distinctive sequence of Late Jurassic sedimentary rock that is 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, siltstone and limestone and is light grey, greenish...
). It was found among mixed fossil remains that included pterosaur
Pterosaur
Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...
and dinosaur material. One notable specimen found with it is the right femur of a derived maniraptora
Maniraptora
Maniraptora is a clade of coelurosaurian dinosaurs which includes the birds and the dinosaurs that were more closely related to them than to Ornithomimus velox. It contains the major subgroups Avialae, Deinonychosauria, Oviraptorosauria and Therizinosauria. Ornitholestes and the Alvarezsauroidea...
n theropod (BYU 2023). BYU 2023 is missing the distal end and is about 63 mm long. It is probably too small to be from the same individual as BYU 2022. BYU 2023 shows apomorphies known only in advanced maniraptorans, including Microvenator
Microvenator
Microvenator is a genus of dinosaur from the Early Cretaceous Cloverly Formation in what is now south central Montana. Microvenator was an oviraptorosaurian theropod. The holotype fossil is an incomplete skeleton, most likely a juvenile, with a living length of about four feet. The adult size of...
, Microraptor
Microraptor
Microraptor is a genus of small, four-winged dromaeosaurid dinosaurs. Numerous well-preserved fossil specimens have been recovered from Liaoning, China...
, and Archaeopteryx.
BYU 2022 and 2023 are important because they are samples of small – bodied maniraptorans from Jurassic North America.