Linhenykus
Encyclopedia
Linhenykus is an extinct genus
of alvarezsaurid
theropod dinosaur
from the Late Cretaceous
of Inner Mongolia
, China
. It is the most basal
known member of the Parvicursorinae. The genus gets its name from Linhe, a city near the site where fossils were first found and Greek onyx, "claw". The specific name is derived from Greek monos, "single", and daktylos, "finger", a reference to the fact that it is the only known non-avian dinosaur to have had but a single digit.
length is 7 centimetres (2.8 in).
Alvarezsauroids are known for their short forelimbs, each with a single greatly enlarged second digit. Although alvarezsaurids were once thought to have only a single digit on each forelimb, more recent evidence has shown that most species had reduced first and third digits. Linhenykus is the first known alvarezsaurid to have only a single, second, digit. Although a reduced third metacarpal is present, the phalanges or finger bones of the first or third digits were probably absent. Despite having the most reduced digits of any alvarezsauroid, Linhenykus was shown by cladistic analysis to have been a basal form as is indicated by the fact that its enlarged digit is not as large or robust as with more advanced forms.
from the Late Cretaceous Wulansuhai Formation in Inner Mongolia, China. The formation dates to the early Campanian
, 84-75 Ma. Linhenykus is currently known from a partial skeleton, holotype
IVPP V17608, including cervical, dorsal, sacral and caudal vertebrae, forelimb, hindlimbs, and pelvis. The genus was first described and named in the Proceedings of the National Academy of Sciences
by Xu Xing, Corwin Sullivan, Pittman, Choiniere, David Hone, Paul Upchurch, Tan Qingwei, Xiao Dong, Lin Tan and Han Fenglu in 2011
.
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 alvarezsaurid
Alvarezsauridae
Alvarezsauridae is an enigmatic family of small, long-legged running dinosaurs. Although originally thought to represent the earliest known flightless birds, a consensus of recent work suggests that they are primitive members of the Maniraptora. Other work found them to be the sister group to the...
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...
from the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
of Inner Mongolia
Inner Mongolia
Inner Mongolia is an autonomous region of the People's Republic of China, located in the northern region of the country. Inner Mongolia shares an international border with the countries of Mongolia and the Russian Federation...
, China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
. It is the most basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
known member of the Parvicursorinae. The genus gets its name from Linhe, a city near the site where fossils were first found and Greek onyx, "claw". The specific name is derived from Greek monos, "single", and daktylos, "finger", a reference to the fact that it is the only known non-avian dinosaur to have had but a single digit.
Description
Linhenykus was small-bodied, being only a few feet in length. FemurFemur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
length is 7 centimetres (2.8 in).
Alvarezsauroids are known for their short forelimbs, each with a single greatly enlarged second digit. Although alvarezsaurids were once thought to have only a single digit on each forelimb, more recent evidence has shown that most species had reduced first and third digits. Linhenykus is the first known alvarezsaurid to have only a single, second, digit. Although a reduced third metacarpal is present, the phalanges or finger bones of the first or third digits were probably absent. Despite having the most reduced digits of any alvarezsauroid, Linhenykus was shown by cladistic analysis to have been a basal form as is indicated by the fact that its enlarged digit is not as large or robust as with more advanced forms.
Discovery
The fossil of Linhenykus was collected by Jonah N. Choiniere and Michael PittmanMichael Pittman
Michael Pittman is an American football running back who is currently a free agent. He was drafted by the Arizona Cardinals in the fourth round of the 1998 NFL Draft. He played college football at Fresno State....
from the Late Cretaceous Wulansuhai Formation in Inner Mongolia, China. The formation dates to the early Campanian
Campanian
The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch . The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma ...
, 84-75 Ma. Linhenykus is currently known from a partial skeleton, holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
IVPP V17608, including cervical, dorsal, sacral and caudal vertebrae, forelimb, hindlimbs, and pelvis. The genus was first described and named in the Proceedings of the National Academy of Sciences
Proceedings of the National Academy of Sciences
The Proceedings of the National Academy of Sciences of the United States of America, usually referred to as PNAS, is the official journal of the United States National Academy of Sciences...
by Xu Xing, Corwin Sullivan, Pittman, Choiniere, David Hone, Paul Upchurch, Tan Qingwei, Xiao Dong, Lin Tan and Han Fenglu in 2011
2011 in paleontology
-Lobopods:-Arachnids:-Insects:-Newly named jawless vertebrates:-Newly named acanthodian:-Newly named cartilaginous fishes:-Newly named bony fishes:-Newly named lepospondyls:-Newly named temnospondyls:-Newly named lissamphibians:...
.