Pinacosaurus
Encyclopedia
Pinacosaurus is a genus
of medium-sized ankylosaur dinosaur
s that lived from the late Santonian
to the late Campanian
stages
of the late Cretaceous
Period (roughly 80–75 million years ago), in Mongolia
and China
. Pinacosaurus had between two and five additional holes near each nostril
, which have not been explained.
Pinacosaurus was a lightly built, medium-sized ankylosaur that reached a length of 5 meters (16 ft) Like all ankylosaurids
, it had a bony club
at the end of its tail which it used as a defensive weapon against predators
such as Velociraptor
. The most unusual element in the original specimen is the presence of two additional egg-shaped holes, one on top of the other, where the nostrils are normally found. The openings are characteristic of the genus, and the number varies: Godefroit et al. described four in 1999, and in 2003 a juvenile specimen with of five pairs of openings was described.
sponsored several Central Asiatic Expeditions to the Gobi Desert
in Mongolia in the 1920s. Among the many paleontological finds from the "Flaming Cliffs" of the Djadokhta Formation in Shabarakh Usu were the original specimens of Pinacosaurus. The holotype
(AMNH 6523) is a partially crushed skull, jaws, and dermal bones collected in 1923.
Pinacosaurus is the best known Asia
n ankylosaur with more than 15 specimens, including one nearly complete skeleton, five skulls or partial skulls, and two finds of several juveniles huddled together, evidently killed by a sandstorm
(Jerzykiewicz, 1993; Burns et al., 2011). The best skull belongs to a juvenile described by Teresa Maryanska
in 1971 and 1977.
Additional remains from China described as P. mephistocephalus by Godefroit et al. in 1999 are considered a valid species based on secondary dermal horns and narial characteristics. The best preserved skulls are from juveniles, but the holotype is an adult skull which is longer than it is wide, which indicates it may be a more basal thyreophora
n.
Originally placed in the family Nodosauridae, it is now considered an ankylosaurid. A simplified cladogram
of its current phylogenetic
placement:
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 medium-sized ankylosaur 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...
s that lived from the late Santonian
Santonian
The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series. It spans the time between 85.8 ± 0.7 mya and 83.5 ± 0.7 mya...
to the late 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 ...
stages
Faunal stage
In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convention have the same name, and the same boundaries.Rock...
of the late Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
Period (roughly 80–75 million years ago), in Mongolia
Mongolia
Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...
and China
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
. Pinacosaurus had between two and five additional holes near each nostril
Nostril
A nostril is one of the two channels of the nose, from the point where they bifurcate to the external opening. In birds and mammals, they contain branched bones or cartilages called turbinates, whose function is to warm air on inhalation and remove moisture on exhalation...
, which have not been explained.
Description
Ankylosauridae
An ankylosaurid is a member of the Ankylosauridae family of armored dinosaurs that evolved 125 million years ago and became extinct 65 million years ago during the Cretaceous-Tertiary extinction event...
, it had a bony club
Club (zoology)
In zoology, a club is a bony mass at the end of the tail of some dinosaurs and of some mammals, most notably the ankylosaurids and the glyptodonts...
at the end of its tail which it used as a defensive weapon against predators
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
such as Velociraptor
Velociraptor
Velociraptor is a genus of dromaeosaurid theropod dinosaur that existed approximately 75 to 71 million years ago during the later part of the Cretaceous Period. Two species are currently recognized, although others have been assigned in the past. The type species is V. mongoliensis; fossils...
. The most unusual element in the original specimen is the presence of two additional egg-shaped holes, one on top of the other, where the nostrils are normally found. The openings are characteristic of the genus, and the number varies: Godefroit et al. described four in 1999, and in 2003 a juvenile specimen with of five pairs of openings was described.
Discoveries
The American Museum of Natural HistoryAmerican Museum of Natural History
The American Museum of Natural History , located on the Upper West Side of Manhattan in New York City, United States, is one of the largest and most celebrated museums in the world...
sponsored several Central Asiatic Expeditions to the Gobi Desert
Gobi Desert
The Gobi is a large desert region in Asia. It covers parts of northern and northwestern China, and of southern Mongolia. The desert basins of the Gobi are bounded by the Altai Mountains and the grasslands and steppes of Mongolia on the north, by the Hexi Corridor and Tibetan Plateau to the...
in Mongolia in the 1920s. Among the many paleontological finds from the "Flaming Cliffs" of the Djadokhta Formation in Shabarakh Usu were the original specimens of Pinacosaurus. 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...
(AMNH 6523) is a partially crushed skull, jaws, and dermal bones collected in 1923.
Pinacosaurus is the best known Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
n ankylosaur with more than 15 specimens, including one nearly complete skeleton, five skulls or partial skulls, and two finds of several juveniles huddled together, evidently killed by a sandstorm
Dust storm
A dust / sand storm is a meteorological phenomenon common in arid and semi-arid regions. Dust storms arise when a gust front or other strong wind blows loose sand and dirt from a dry surface. Particles are transported by saltation and suspension, causing soil to move from one place and deposition...
(Jerzykiewicz, 1993; Burns et al., 2011). The best skull belongs to a juvenile described by Teresa Maryanska
Teresa Maryanska
Teresa Maryańska is a Polish paleontologist who has specialized in Mongolian dinosaurs, particularly pachycephalosaurians and ankylosaurians. A member of the 1964, 1965, 1970, and 1971 Polish–Mongolian expeditions to the Gobi Desert, she has described many finds from these rocks, often with...
in 1971 and 1977.
Classification
The original species is P. grangeri. Young discovered a new specimen in the Ningxia Province, and described it as a new species P. ninghsiensis in 1935, but it is now considered to the same species as P. grangeri; as are fragmentary remains described as Syrmosaurus viminicaudus by Maleev in 1952.Additional remains from China described as P. mephistocephalus by Godefroit et al. in 1999 are considered a valid species based on secondary dermal horns and narial characteristics. The best preserved skulls are from juveniles, but the holotype is an adult skull which is longer than it is wide, which indicates it may be a more basal thyreophora
Thyreophora
The Thyreophora were a subgroup of the ornithischian dinosaurs...
n.
Originally placed in the family Nodosauridae, it is now considered an ankylosaurid. A simplified cladogram
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
of its current phylogenetic
Phylogenetics
In biology, phylogenetics is the study of evolutionary relatedness among groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...
placement:
External links
- Paper about the feet and behavior of Pinacosaurus by Currie et.al.