Shaochilong
Encyclopedia
Shaochilong is a genus
of carcharodontosaurid
dinosaur
from the mid Cretaceous
(Turonian
stage) Ulansuhai Formation
of China
(about 92 million years ago). The type species
, S. maortuensis, was originally named Chilantaisaurus
maortuensis, but was re-described and reclassified in 2009.
, IVPP V2885.1-7, consisting of skull fragments, axis and six caudal vertebrae associated to a single individual is the only known specimen. This specimen was discovered in Outer Mongolia and described by Hu in 1964 as a species of Chilantaisaurus
. Chure (2002) and Rauhut (2001) suggested that it did not belong to that genus, and was probably a primitive coelurosaur. However, a re-description by Brusatte and colleagues in 2009 found that it was in fact a carcharodontosaurid, the first recognized from Asia. The genus was originally informally
named "Alashansaurus".
IVPP V2885.1 was probably adult or nearly adult individual. Its length – based on the length of the maxillary tooth row – is estimated of 5 to 6 m (16.4 to 19.7 ft). Estimated length of the femur
is 61.5 cm, what suggests that whole animal weighted approximately 500 kilograms (1,102.3 lb).
Phylogenetic analysis performed by Brusatte and coworkers indicate that Shaochilong is deeply nested within the carchorodontosaurids, the most derived group among the allosauroids. Surprisingly, Shaochilong appears to be more closely related to the Gondwanan carcharodontosaurids (Tyrannotitan
, Carcharodontosaurus
, Mapusaurus
, Giganotosaurus
) than the Laurasian ones (such as Neovenator
and Acrocanthosaurus
). Shaochilong is the youngest known Laurasian allosauroid suggesting that basal tetanurans not tyrannosaurids, were still the dominant group of large-bodied theropods in Laurasian during the Mid-Cretaceous and that the rise of tyrannosaurids as the dominant group of large terrestrial predators was sudden and confined to the very end of the Cretaceous.
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 carcharodontosaurid
Carcharodontosauridae
Carcharodontosaurids were a group of carnivorous theropod dinosaurs. In 1931 Ernst Stromer named Carcharodontosauridae as a family, in modern paleontology this name indicates a clade within Carnosauria...
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 mid 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...
(Turonian
Turonian
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.5 ± 0.8 Ma and 89.3 ± 1 Ma...
stage) Ulansuhai Formation
Ulansuhai Formation
The Ulansuhai Formation is a geological formation in Inner Mongolia, north China. Dinosaur remains are among the fossils that have been recovered from the formation....
of 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...
(about 92 million years ago). 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...
, S. maortuensis, was originally named Chilantaisaurus
Chilantaisaurus
Chilantaisaurus is a genus of neovenatorid theropod dinosaur from the late Cretaceous Ulansuhai Formation of China . The type species, C. tashuikouensis, was described by Hu in 1964. Chilantaisaurus was a large theropod, estimated as weighing between and...
maortuensis, but was re-described and reclassified in 2009.
Discovery and subsequent analysis
The holotypeHolotype
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 V2885.1-7, consisting of skull fragments, axis and six caudal vertebrae associated to a single individual is the only known specimen. This specimen was discovered in Outer Mongolia and described by Hu in 1964 as a species of Chilantaisaurus
Chilantaisaurus
Chilantaisaurus is a genus of neovenatorid theropod dinosaur from the late Cretaceous Ulansuhai Formation of China . The type species, C. tashuikouensis, was described by Hu in 1964. Chilantaisaurus was a large theropod, estimated as weighing between and...
. Chure (2002) and Rauhut (2001) suggested that it did not belong to that genus, and was probably a primitive coelurosaur. However, a re-description by Brusatte and colleagues in 2009 found that it was in fact a carcharodontosaurid, the first recognized from Asia. The genus was originally informally
Nomen nudum
The phrase nomen nudum is a Latin term, meaning "naked name", used in taxonomy...
named "Alashansaurus".
IVPP V2885.1 was probably adult or nearly adult individual. Its length – based on the length of the maxillary tooth row – is estimated of 5 to 6 m (16.4 to 19.7 ft). Estimated length of the 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...
is 61.5 cm, what suggests that whole animal weighted approximately 500 kilograms (1,102.3 lb).
Classification
| {clade| style=font-size:75%;line-height:75% | label1= Carcharodontosauridae Carcharodontosauridae Carcharodontosaurids were a group of carnivorous theropod dinosaurs. In 1931 Ernst Stromer named Carcharodontosauridae as a family, in modern paleontology this name indicates a clade within Carnosauria... |
1= }} Note: this cladogram Cladogram A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational... follows a 2009 analysis by Brusatte et al. |
Phylogenetic analysis performed by Brusatte and coworkers indicate that Shaochilong is deeply nested within the carchorodontosaurids, the most derived group among the allosauroids. Surprisingly, Shaochilong appears to be more closely related to the Gondwanan carcharodontosaurids (Tyrannotitan
Tyrannotitan
Tyrannotitan is a genus of huge bipedal carnivorous dinosaur of the carcharodontosaurid family from the Aptian stage of the early Cretaceous period, discovered in Argentina. It is closely related to other giant predators like Giganotosaurus and Carcharodontosaurus...
, Carcharodontosaurus
Carcharodontosaurus
Carcharodontosaurus was a gigantic carnivorous carcharodontosaurid dinosaur that lived around 100 to 93 million years ago, during the late Albian to early Cenomanian stages of the mid-Cretaceous Period...
, Mapusaurus
Mapusaurus
Mapusaurus was a giant carnosaurian dinosaur from the early Late Cretaceous of what is now Argentina. It was similar in size to its close relative Giganotosaurus, with the largest known individuals estimated as over in length and weighing approximately...
, Giganotosaurus
Giganotosaurus
Giganotosaurus is a genus of carcharodontosaurid dinosaur that lived around 97 million years ago during the early Cenomanian stage of the Late Cretaceous Period. It included some of the largest known terrestrial carnivores, slightly larger than the largest Tyrannosaurus, but smaller than the...
) than the Laurasian ones (such as Neovenator
Neovenator
Neovenator is a genus of allosauroid dinosaur. Since its discovery on the Isle of Wight, UK, it has become one of the best-known large carnivorous dinosaurs in Europe. Neovenator was at first considered possibly a new species of Megalosaurus. It measured approximately 7.5 meters in length,...
and Acrocanthosaurus
Acrocanthosaurus
Acrocanthosaurus is a genus of theropod dinosaur that existed in what is now North America during the Aptian and early Albian stages of the Early Cretaceous. Like most dinosaur genera, Acrocanthosaurus contains only a single species, A. atokensis. Its fossil remains are found mainly in the U.S...
). Shaochilong is the youngest known Laurasian allosauroid suggesting that basal tetanurans not tyrannosaurids, were still the dominant group of large-bodied theropods in Laurasian during the Mid-Cretaceous and that the rise of tyrannosaurids as the dominant group of large terrestrial predators was sudden and confined to the very end of the Cretaceous.
External links
- Shark toothed theropods in Asia – introducing Shaochilong Discoverers' blog