Shantungosuchus
Encyclopedia
Shantungosuchus is an extinct genus
of Cretaceous
crocodyliform found in China
. It includes three species
: Shantungosuchus chuhsienensis, and S. brachycephalus, which were both described by Yang Zhongjian
– usually referred to as "Young" – in 1961 and 1982, and S. hangjinensis, which was described by Xiao-Chun Wu et al in 1994. S. chuhsienensis is the type for this genus.
romanization of Mandarin characters for Shandong
, a province located on the eastern coast of the People's Republic of China
, where it was first discovered. The second part, suchus is a Latin word meaning "crocodile".
Shantungosuchus belongs to Protosuchia
, a group of early crocodilian relatives that were all rather small in size, about 1 meter in length, and terrestrial rather than aquatic. They are most easily distinguished from other crocodylians by their short premaxilla
and maxilla
s, a transversely broad shelf on the jugal bone, and a pair of posterolaterally divergent ridges on the pterygoid
, and two large depressions on the sphenoid bone
. The angular shape of the rest of the skull is absent from the posterolateral section of the jaw. The dentaries near the symphysis
are superficially asymmetrical. All known forms of Shantungosuchus also have a square-shaped fossa
on the jugal, and a leaf-shaped palatine bone
.
by several different authors from the 1960s to the 1980s,.
However, in Xiao-Chun Wu's 1994 description of S. hangjinensis, he noted the bones were more similar to the family Protosuchidae
rather than Atoposauridae, and proposed to classify it as such.
Protosuchia has recently been considered a paraphyletic grouping of early crocodyliforms. Protosuchia is now commonly split into two groups: the basal family Protosuchidae
, which is a true clade
, and a group of basal crocodyliforms more closely related to Hsisosuchus
and Mesoeucrocodylia
. Shantungosuchus is included in the latter grouping, as it is more closely related to mesoeucrocodylians than the protosuchid protosuchians.
deposits in its namesake Shandong province. Also from the Jurassic of Shandong is S. brachycephalus. S. hangjinensis, however, is slightly younger, and is found in the lower Cretaceous Luohandong Formation
of Outer Mongolia
. The Luohandong formation provides clues to Shantungosuchus' environment. For instance, S. hangjinensis likely shared its habitat
with fish such as Sinamia
, the turtle Orodsemys, and another species of crocodile-like reptile called Ikechosaurus
, and several types of dinosaurs- though none have been identified to the level of genus.
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 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...
crocodyliform found in 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 includes three species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
: Shantungosuchus chuhsienensis, and S. brachycephalus, which were both described by Yang Zhongjian
Yang Zhongjian
Yang Zhongjian , courtesy name Keqiang , also known as C.C. Young, was one of China's foremost paleontologists. He has been called the 'Father of Chinese vertebrate paleontology'...
– usually referred to as "Young" – in 1961 and 1982, and S. hangjinensis, which was described by Xiao-Chun Wu et al in 1994. S. chuhsienensis is the type for this genus.
Etymology
The primary part of Shantungosuchus name comes from Shan-tung, a Wade-GilesWade-Giles
Wade–Giles , sometimes abbreviated Wade, is a romanization system for the Mandarin Chinese language. It developed from a system produced by Thomas Wade during the mid-19th century , and was given completed form with Herbert Giles' Chinese–English dictionary of 1892.Wade–Giles was the most...
romanization of Mandarin characters for Shandong
Shandong
' is a Province located on the eastern coast of the People's Republic of China. Shandong has played a major role in Chinese history from the beginning of Chinese civilization along the lower reaches of the Yellow River and served as a pivotal cultural and religious site for Taoism, Chinese...
, a province located on the eastern coast of the People's Republic of 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...
, where it was first discovered. The second part, suchus is a Latin word meaning "crocodile".
Description
S. chuhsienenis was first described from an articulated skeleton that was preserved as an impression of its ventral surface. Its small size, slender body, and triangular skull made it distinct from other atoposaurids.Shantungosuchus belongs to Protosuchia
Protosuchia
Protosuchia is a group of extinct Mesozoic crocodyliforms. They were small in size and terrestrial. In phylogenetic terms, Protosuchia is considered an informal group because it is a grade of basal crocodyliforms, not a true clade....
, a group of early crocodilian relatives that were all rather small in size, about 1 meter in length, and terrestrial rather than aquatic. They are most easily distinguished from other crocodylians by their short premaxilla
Premaxilla
The incisive bone is the portion of the maxilla adjacent to the incisors. It is a pair of small cranial bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. They are connected to the maxilla and the nasals....
and maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
s, a transversely broad shelf on the jugal bone, and a pair of posterolaterally divergent ridges on the pterygoid
Pterygoid processes of the sphenoid
The pterygoid processes of the sphenoid, one on either side, descend perpendicularly from the regions where the body and great wings unite.Each process consists of a medial pterygoid plate and a lateral pterygoid plate, the upper parts of which are fused anteriorly; a vertical sulcus, the...
, and two large depressions on the sphenoid bone
Sphenoid bone
The sphenoid bone is an unpaired bone situated at the base of the skull in front of the temporal bone and basilar part of the occipital bone.The sphenoid bone is one of the seven bones that articulate to form the orbit...
. The angular shape of the rest of the skull is absent from the posterolateral section of the jaw. The dentaries near the symphysis
Symphysis
A symphysis is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint, specifically a secondary cartilaginous joint.1.A symphysis is an amphiarthrosis, a slightly movable joint.2.A growing together of parts or structures...
are superficially asymmetrical. All known forms of Shantungosuchus also have a square-shaped fossa
Fossa (anatomy)
In anatomical terminology, fossa has come to mean a depression or hollow, in general, in a bone. Other parts of the body may be involved, for example, the antecubital fossa...
on the jugal, and a leaf-shaped palatine bone
Palatine bone
The palatine bone is a bone in many species of the animal kingdom, commonly termed the palatum .-Human anatomy:...
.
Taxonomy
Two of the species of Shantungosuchus, including the type, were described by Yang Zhongjian (referenced here as C.C. (Chung Chien) Young) in 1961. Since the description of S.chuhsienensis, there has been uncertainty about the placement of the genus. It was suggested to be an atoposauridAtoposauridae
Atoposauridae is a family of crocodile-like archosaurs. Members of the family have been found from France, Spain, Portugal, Romania, Germany, Kazakhstan, the United Kingdom, the United States, Cameroon, and Thailand.-Phylogeny:...
by several different authors from the 1960s to the 1980s,.
However, in Xiao-Chun Wu's 1994 description of S. hangjinensis, he noted the bones were more similar to the family Protosuchidae
Protosuchidae
Protosuchidae was a family of crocodylmorph reptiles from the Late Triassic, Jurassic, and Cretaceous time periods.-Distribution:Triassic protosuchids are known from Lesotho and Arizona. Jurassic protosuchids are known from Nova Scotia, Poland, South Africa, and Arizona...
rather than Atoposauridae, and proposed to classify it as such.
Protosuchia has recently been considered a paraphyletic grouping of early crocodyliforms. Protosuchia is now commonly split into two groups: the basal family Protosuchidae
Protosuchidae
Protosuchidae was a family of crocodylmorph reptiles from the Late Triassic, Jurassic, and Cretaceous time periods.-Distribution:Triassic protosuchids are known from Lesotho and Arizona. Jurassic protosuchids are known from Nova Scotia, Poland, South Africa, and Arizona...
, which is a true 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...
, and a group of basal crocodyliforms more closely related to Hsisosuchus
Hsisosuchus
Hsisosuchus is an extinct genus of crocodyliform from China. Currently there are three species within this genus. H. chungkingensis and H. chowi are from the Late Jurassic. H. dashanpuensis is from the Middle Jurassic....
and Mesoeucrocodylia
Mesoeucrocodylia
Mesoeucrocodylia is the name of the clade that includes Eusuchia and the paraphyletic group Mesosuchia. The group appeared during the Early Jurassic, and continues to the present day....
. Shantungosuchus is included in the latter grouping, as it is more closely related to mesoeucrocodylians than the protosuchid protosuchians.
Distribution and habitat
Shantungosuchus chuhsienensis, aside from being the type species, is also the oldest. It was found in upper JurassicJurassic
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...
deposits in its namesake Shandong province. Also from the Jurassic of Shandong is S. brachycephalus. S. hangjinensis, however, is slightly younger, and is found in the lower Cretaceous Luohandong Formation
Luohandong Formation
The Luohandong Formation is a Mesozoic geologic formation. Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus.-See also:* List of dinosaur-bearing rock formations...
of Outer Mongolia
Outer Mongolia
Outer Mongolia was a territory of the Qing Dynasty = the Manchu Empire. Its area was roughly equivalent to that of the modern state of Mongolia, which is sometimes informally called "Outer Mongolia" today...
. The Luohandong formation provides clues to Shantungosuchus' environment. For instance, S. hangjinensis likely shared its habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
with fish such as Sinamia
Sinamia
Sinamia is an extinct genus of bowfin fish which existed in China during the early Cretaceous period. It contains the species Sinamia zdanskyi....
, the turtle Orodsemys, and another species of crocodile-like reptile called Ikechosaurus
Ikechosaurus
Ikechosaurus is an extinct genus of choristoderan which existed in China and Mongolia during the Cretaceous period. It contains the species Ikechosaurus sunailinae and Ikechosaurus gaoi....
, and several types of dinosaurs- though none have been identified to the level of genus.
See also
- List of crurotarsans
- NeuquensuchusNeuquensuchusNeuquensuchus is an extinct genus of basal crocodyliform from the Santonian-age Upper Cretaceous Bajo de la Carpa Formation of Neuquén Province, Argentina. The known remains were discovered on the campus of Universidad Nacional del Comahue in the city of Neuquén. Neuquensuchus was named by Lucas...
- SichuanosuchusSichuanosuchusSichuanosuchus is an extinct genus of crocodylomorph from the Late Jurassic and possibly Early Cretaceous of China.-References:* Chinese Fossil Vertebrates by Spencer G. Lucas...
- ZosuchusZosuchusZosuchus is a genus of basal, Late Cretaceous crocodyliform from the Redbeds of Zos Canyon in the Gobi Desert of Mongolia. It was discovered by expeditions organized by the American Museum of Natural History, and described by palaeontologists Diego Pol and Mark Norell.The type species is Z...
- TzaganosuchusTzaganosuchusTzaganosuchus is an extinct genus of fossil crocodile from the Gobi Desert of southern/southeastern Mongolia. The type and only known species for this genus, Tzaganosuchus infansis was discovered during a joint paleontological expedition conducted by the Soviet Union and Mongolia...