Linhevenator
Encyclopedia
Linhevenator is a genus
of short-armed troodontid
theropod dinosaur
from the Late Cretaceous
(Campanian
) Bayan Mandahu Formation
of Bayan Mandahu, Inner Mongolia
, China
.
The type species
Linhevenator tani was named and described in 2011
by Xu Xing, Tan Qingwei, Corwin Sullivan, Han Fenglu and Xiao Dong
. The generic name combines a reference to the Linhe region with a Latin
venator, "hunter". The specific name honours Professor Tan Lin.
The holotype
of Linhevenator is specimen LHV0021, a partial skeleton of an adult individual, including a cranium and mandible
, six dorsal vertebrae, a right scupula, a right humerus
, the ilia
, a left femur
and a left foot. It was found in 2009 and represents the most complete troodontid remains known from the Upper Cretaceous. Its four autapomorphies (unique traits) include a jugal
with a lateral flange, a surangular crest that is anteroventrally oriented, the presence of medial expansion near the distal end of the femur, and a wide longitudinal groove present along the distal third of the dorsal surface of the third metatarsal.
Linhevenator is a rather large troodontid with an estimated body weight of twenty-three kilogrammes. The arms are relatively short but the humerus is very robust. The describers suggest the arm might have been used for digging or climbing. The first toe was preserved in a lateral position, instead of pointing forwards. Linhevenator has a dromaeosaurid-like pedal digit II
, carrying a sickle-claw larger than that of basal troodontids.
Linhevenator was assigned to the Troodontidae
by the describers. It possesses a combination of "primitive" (basal
) and derived characters, but was found to be a derived troodontid in a phylogenetic analysis, in a polytomy
with Troodon
and a clade
formed by Zanabazar and Saurornithoides
. This position was seen by the authors as an indication for an evolutionary trend in the Troodontidae of shortening the forelimbs and for a parallel evolution
of large sickle-claws with both the troodontids and the dromaeosaurids.
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 short-armed troodontid
Troodontidae
Troodontidae is a family of bird-like theropod dinosaurs. During most of the 20th century, troodontid fossils were few and scrappy and they have therefore been allied, at various times, with many dinosaurian lineages...
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...
(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 ...
) Bayan Mandahu Formation
Bayan Mandahu Formation
The Bayan Mandahu Formation is a geological unit of "redbeds" located near the village of Bayan Mandahu in Inner Mongolia, China Asia and dates from the Late Cretaceous Period...
of Bayan Mandahu, 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...
.
The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
Linhevenator tani was named and described 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:...
by Xu Xing, Tan Qingwei, Corwin Sullivan, Han Fenglu and Xiao Dong
Xiao Dong
Xiao Dung , courtesy name Yuanji , sometimes known by his pre-ascension title of Prince of Yuzhang , was briefly an emperor of the Chinese Liang Dynasty...
. The generic name combines a reference to the Linhe region with a Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
venator, "hunter". The specific name honours Professor Tan Lin.
The 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...
of Linhevenator is specimen LHV0021, a partial skeleton of an adult individual, including a cranium and mandible
Mandible
The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...
, six dorsal vertebrae, a right scupula, a right humerus
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
, the ilia
Ilium (bone)
The ilium is the uppermost and largest bone of the pelvis, and appears in most vertebrates including mammals and birds, but not bony fish. All reptiles have an ilium except snakes, although some snake species have a tiny bone which is considered to be an ilium.The name comes from the Latin ,...
, a left femur
Femur
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...
and a left foot. It was found in 2009 and represents the most complete troodontid remains known from the Upper Cretaceous. Its four autapomorphies (unique traits) include a jugal
Jugal
The jugal is a skull bone found in most reptiles, amphibians, and birds. In mammals, the jugal is often called the malar or Zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species....
with a lateral flange, a surangular crest that is anteroventrally oriented, the presence of medial expansion near the distal end of the femur, and a wide longitudinal groove present along the distal third of the dorsal surface of the third metatarsal.
Linhevenator is a rather large troodontid with an estimated body weight of twenty-three kilogrammes. The arms are relatively short but the humerus is very robust. The describers suggest the arm might have been used for digging or climbing. The first toe was preserved in a lateral position, instead of pointing forwards. Linhevenator has a dromaeosaurid-like pedal digit II
Digit (anatomy)
A digit is one of several most distal parts of a limb, such as fingers or toes, present in many vertebrates.- Names:Some languages have different names for hand and foot digits ....
, carrying a sickle-claw larger than that of basal troodontids.
Linhevenator was assigned to the Troodontidae
Troodontidae
Troodontidae is a family of bird-like theropod dinosaurs. During most of the 20th century, troodontid fossils were few and scrappy and they have therefore been allied, at various times, with many dinosaurian lineages...
by the describers. It possesses a combination of "primitive" (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:...
) and derived characters, but was found to be a derived troodontid in a phylogenetic analysis, in a polytomy
Polytomy
A polytomy , meaning many temporal based branches, is a section of a phylogeny in which the evolutionary relationships can not be fully resolved to dichotomies. In a phylogenetic tree, a polytomy is represented as a node which has more than two immediate descending branches...
with Troodon
Troodon
Troodon is a genus of relatively small, bird-like dinosaur from the Late Cretaceous period . Discovered in 1855, it was among the first dinosaurs found in North America...
and a clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
formed by Zanabazar and Saurornithoides
Saurornithoides
Saurornithoides is a genus of troodontid maniraptoran dinosaur, living during the Late Cretaceous period. These creatures were predators, which could run fast on their hind legs and had excellent sight and hearing...
. This position was seen by the authors as an indication for an evolutionary trend in the Troodontidae of shortening the forelimbs and for a parallel evolution
Parallel evolution
Parallel evolution is the development of a similar trait in related, but distinct, species descending from the same ancestor, but from different clades.-Parallel vs...
of large sickle-claws with both the troodontids and the dromaeosaurids.