| Shantungosuchus | |
|---|---|
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Archosauria |
| Clade: | Pseudosuchia |
| Clade: | Crocodylomorpha |
| Clade: | Mesoeucrocodylia |
| Clade: | †Shartegosuchoidea |
| Genus: | †Shantungosuchus Yang, 1961 |
| Species | |
Shantungosuchus is anextinctgenus ofEarly Cretaceouscrocodyliform found inChina. It includes threespecies:Shantungosuchus chuhsienensis andS. brachycephalus, which were both described byYang Zhongjian – usually referred to as "Young" – in 1961 and 1982, andS. hangjinensis, which was described by Xiao-Chun Wuet al in 1994.S. chuhsienensis is thetype for this genus.
The primary part ofShantungosuchus' name comes fromShan-tung, theWade-Giles romanization ofShandong (simplified Chinese:山东;traditional Chinese:山東;pinyin:Shāndōng;Wade–Giles:Shan1tung1), aprovince located on the eastern coast of thePeople's Republic of China, where it was first discovered. The second part,suchus is anAncient Greek word referring to the Egyptian crocodile deitySobek that is commonly used as a suffix forcrocodylomorph genera and crocodile-like animals in general.
Shantungosuchus chuhsienenis was first described from an articulated skeleton that was preserved as an impression of itsventral surface. Its small size, slender body, and triangular skull made it distinct from other atoposaurids.[1] Its total length is only about 30 cm (12 in).[2]
Shantungosuchus belongs toProtosuchia, a group of early crocodilian relatives that were all rather small in size, about 1 meter in length, and terrestrial rather than aquatic.[3] They are most easily distinguished from other crocodylians by their shortpremaxilla andmaxillas, a transversely broad shelf on thejugal bone, and a pair of posterolaterally divergent ridges on thepterygoid, and two large depressions on thesphenoid bone. The angular shape of the rest of the skull is absent from the posterolateral section of the jaw. The dentaries near thesymphysis are superficially asymmetrical. All known forms of Shantungosuchus also have a square-shapedfossa on the jugal, and a leaf-shapedpalatine bone.
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 ofS. chuhsienensis, there has been uncertainty about the placement of the genus. It was suggested to be anatoposaurid by several different authors from the 1960s to the 1980s,.[4][5][6]However, in Xiao-Chun Wu's 1994 description ofS. hangjinensis, he noted the bones were more similar to the familyProtosuchidae rather than Atoposauridae, and proposed to classify it as such.[1]
Protosuchia has recently been considered aparaphyletic grouping of early crocodyliforms. Protosuchia is now commonly split into two groups: the basal familyProtosuchidae, which is a trueclade, and a group of basal crocodyliforms more closely related toHsisosuchus andMesoeucrocodylia. Clark et al. (2004) recoveredShantungosuchus as closely related to mesoeucrocodylians, and Buscalioni (2017) found the genus to group in a clade withSichuanosuchus andShartegosuchidae,[7][8] which was formally namedShartegosuchoidea by Dollman et al. (2018) in their description of a newShartegosuchus specimen.[9]
Shantungosuchus chuhsienensis has been found in the Early Cretaceous (Barremian-Aptian)Mengyin Formation of Shandong province.[1]S. hangjinensis, however, is slightly younger, and is found in the lower CretaceousLuohandong Formation ofOuter Mongolia, andS. brachycephalus may also have been found in the same region.[1][10] The Luohandong formation provides clues to the environment ofShantungosuchus. For instance,S. hangjinensis likely shared itshabitat with fish such asSinamia, the turtleOrdosemys, and another species of crocodile-like reptile calledIkechosaurus, and several types ofdinosaurs- though none have been identified to the level of genus.[11][12]
