''Shantungosuchus'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

crocodyliform Crocodyliformes is a clade of Crurotarsi, crurotarsan archosaurs, the group often traditionally referred to as "crocodilians". They are the first members of Crocodylomorpha to possess many of the features that define later relatives. They are the ...

found in

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

. It includes three

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

: ''Shantungosuchus chuhsienensis'' and ''S. brachycephalus'', which were both described by

Yang Zhongjian Yang Zhongjian, also Yang Chung-chien (; 1 June 1897 – 15 January 1979), courtesy name Keqiang (), also known as C.C. (Chung Chien) Young, was a Chinese paleontologist and zoologist. He was one of China's foremost vertebrate paleontologists. ...

– usually referred to as "Young" – in 1961 and 1982, and ''S. hangjinensis'', which was described by Xiao-Chun Wu

et al References Notes References Further reading * * External links * {{Latin phrases E ...

in 1994. ''S. chuhsienensis'' is the

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * ...

for this genus.

Etymology

The primary part of ''Shantungosuchus name comes from ''Shan-tung'', the Wade-Giles romanization of ''

Shandong Shandong is a coastal Provinces of China, province in East China. Shandong has played a major role in Chinese history since the beginning of Chinese civilization along the lower reaches of the Yellow River. It has served as a pivotal cultural ...

'' (), a

province A province is an administrative division within a country or sovereign state, state. The term derives from the ancient Roman , which was the major territorial and administrative unit of the Roman Empire, Roman Empire's territorial possessions ou ...

located on the eastern coast of the

People's Republic of China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

, where it was first discovered. The second part, ''suchus'' is an

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

word referring to the Egyptian crocodile deity

Sobek Sobek (), also known as Suchus (), was an ancient Egyptian deities, ancient Egyptian deity with a complex and elastic history and nature. He is associated with the Nile crocodile and is often represented as a crocodile-headed humanoid, if not a ...

that is commonly used as a suffix for

crocodylomorph Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. Extinct crocodylomorphs were considerably mor ...

genera and crocodile-like animals in general.

Description

''Shantungosuchus chuhsienenis'' was first described from an articulated skeleton that was preserved as an impression of its

ventral Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

surface. Its small size, slender body, and triangular skull made it distinct from other atoposaurids. Its total length is only about . ''Shantungosuchus'' belongs to

Protosuchia Protosuchia is a group of extinct Mesozoic crocodyliforms. They were small in size (~1 meter in length) and Terrestrial animal, terrestrial. In phylogenetic terms, Protosuchia is considered an informal group because it is a evolutionary grade, gr ...

, 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 The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammals h ...

and

maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...

s, a transversely broad shelf on the

jugal bone The jugal is a skull bone found in most reptiles, amphibians and birds. In mammals, the jugal is often called the malar or zygomatic bone, zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by spe ...

, and a pair of posterolaterally divergent ridges on the

pterygoid Pterygoid, from the Greek for 'winglike', may refer to: * Pterygoid bone, a bone of the palate of many vertebrates * Pterygoid processes of the sphenoid bone ** Lateral pterygoid plate ** Medial pterygoid plate * Lateral pterygoid muscle * Medial ...

, and two large depressions on the

sphenoid bone The sphenoid bone is an unpaired bone of the neurocranium. It is situated in the middle of the skull towards the front, in front of the basilar part of occipital bone, basilar part of the occipital bone. The sphenoid bone is one of the seven bon ...

. The angular shape of the rest of the skull is absent from the posterolateral section of the jaw. The dentaries near the

symphysis A symphysis (, : symphyses) is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint, specifically a secondary cartilaginous joint. # A symphysis is an amphiarthrosis, a slightly movable joint. # A growing together o ...

are superficially asymmetrical. All known forms of Shantungosuchus also have a square-shaped fossa on the jugal, and a leaf-shaped

palatine bone In anatomy, the palatine bones (; derived from the Latin ''palatum'') are two irregular bones of the facial skeleton in many animal species, located above the uvula in the throat. Together with the maxilla, they comprise the hard palate. Stru ...

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 atoposaurid 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 Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

grouping of early crocodyliforms. Protosuchia is now commonly split into two groups: the basal family Protosuchidae, which is a true

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

, and a group of basal crocodyliforms more closely related to '' Hsisosuchus'' and Mesoeucrocodylia. Clark et al. (2004) recovered ''Shantungosuchus'' as closely related to mesoeucrocodylians, and Buscalioni (2017) found the genus to group in a clade with ''Sichuanosuchus'' and Shartegosuchidae, which was formally named Shartegosuchoidea by Dollman et al. (2018) in their description of a new ''Shartegosuchus'' specimen.

Distribution and habitat

''Shantungosuchus chuhsienensis'' has been found in the Early Cretaceous (

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 125.77 Ma (million years ago) and 121.4 ± 1.0 Ma (Historically, this stage was placed at 129.4 million to approximately 125 million years ago) It is a ...

Aptian The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), S ...

) Mengyin Formation of Shandong province. ''S. hangjinensis'', however, is slightly younger, and is found in the lower Cretaceous Luohandong Formation of

Outer Mongolia Outer Mongolia was the name of a territory in the Manchu-led Qing dynasty of China from 1691 to 1911. It corresponds to the modern-day independent state of Mongolia and the Russian republic of Tuva. The historical region gained ''de facto'' ...

, and ''S. brachycephalus'' may also have been found in the same region.Lü, J. & Wu, X-C. 1996 Restudy of Shantungosuchus brachycephalus Young, 1982. Vert. PalAs. 34, 184-201. The Luohandong formation provides clues to the environment of ''Shantungosuchus''. For instance, ''S. hangjinensis'' likely shared its

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

with fish such as '' Sinamia'', the turtle '' Ordosemys'', and another species of crocodile-like reptile called '' Ikechosaurus'', and several types of

dinosaurs Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

- though none have been identified to the level of genus.

References

External links