Jia et al., 2007
In 2002, Liu Yongfei discovered the remains of a stegosaurian. These were secured by a Sino-American expedition and prepared by Xiang Lishi and Ding Xiaoqing.
The type species, Jiangjunosaurus junggarensis, was named and described by Jia Chengkai, Catherine Foster, Xu Xing and James Clark in 2007. The generic name refers to the abandoned town of Jiangjunmiao. Jiangjun, 將 軍, is "general" in Chinese and the town's name, the "temple of the general", has been explained by the burial of one. The specific name refers to the provenance from the Junggar.
The holotype, IVPP V 14724, was found in a layer of the Shishugou Formation, dating from the Oxfordian. It includes the lower jaws, some rear skull bones, eleven neck vertebrae, ribs, a scapula, a coracoid, and two neck plates. These elements were found in almost perfect articulation. It represents a subadult individual.
The describers established three distinguishing traits: the crowns of the teeth are symmetrical and in side view wider than tall; the spine of the axis, the second neck vertebra, has a rectangular profile in side view, instead of a triangular one; and the rear neck vertebrae have large vein openings in their sides.
The skull of Jiangjunosaurus is relatively elongated, the maximum width above the postorbitals probably measuring 35% of the skull length. There are at least fourteen teeth in the maxilla. The quadratojugal has a robust horizontal front branch and a thin short vertical branch, only half as tall as the quadrate shaft. There is no clear foramen paraquadraticum, opening between the quadrate and quadratojugal. The quadrate is inclined to the rear and has a depression on its flange contacting the pterygoid. There is no clear opening between the front branches of the pterygoids.
The predentary, the bone core of the lower beak placed on the fronts of both lower jaws, has a deep and hooked "chin". Between the predentary and the tooth row a gap is present equal to about four tooth positions. From the rear part of a bone shelf at the outside of the tooth row a vertical plate extends upwards obscuring that row in side view. The plate continues to the rear into a high coronoid process. Between dentary, surangular and angular a rather tall triangular mandibular fenestra is present.
The dentary bears twenty-one teeth, which are slightly larger than those of the upper jaws. All teeth of Jiangjunosaurus are symmetrical with a triangular profile. Front and rear edges have both seven denticles. In side view the teeth are broad, about as wide as tall. Both their inner and outer sides are convexly curved from the front to the rear. The usual vertical ridges are present but weakly developed; the frontmost and rearmost teeth lack them completely. Primary vertical ridges in the middle are absent.
Of the neck vertebrae the second, the axis, has a neural spine or processus spinosus that is rectangular in side view, due to a higher than normal front edge. It is elongated and rather low. From the fifth cervical vertebra onwards large depressions appear on the lower rear side of the vertebral body. These are pierced by large openings that become progressively wider further back in the series. These foramina are superficially very similar to the pneumatic openings with Saurischia. However, CAT-scans of the Jiangjunosaurus fossils revealed that the openings are not connected to inner air spaces and thus probably served as vein channels. Some dorsal ribs have a crescent-shaped flange at their lower ends.
Two neck plates have been preserved, probably in their original position. One is positioned above the axis, the other above the third cervical. The plates are roughly circular or diamond-shaped in form. They are slightly taller than wide in side view, have an obtuse triangular top and a constricted base. The bases are transversely thicker than the top sections, which show a pattern of fine diverging ridges. The plates are positioned to the right of the neural spines and the describers assumed two rows were originally present.
Jiangjunosaurus was placed in the Stegosauridae in 2007. The describers concluded that within the Stegosauridae it had a basal position. This was not based on an exact cladistic analysis but on the method of comparative anatomy. Jiangjunosaurus shows a mix of basal and derived traits. Characters that are typically stegosaurid are the inclined quadrate; the vertical plate on the dentary; the depression on the pterygoid flange of the quadrate; the bottom edge of the scapula exceeding the upper edge of the coracoid in length; and the double row of larger neck plates. A basal stegosaurid position is suggested by the horizontal front branch of the quadratojugal combined with a ventral process on the main body.
Acantholipan is a genus of herbivorous nodosaurid dinosaur from Mexico from the early Santonian age of the Late Cretaceous. It includes one species, Acantholipan gonzalezi.Ankylosaurinae
Ankylosaurinae is a subfamily of ankylosaurid dinosaurs, existing from the Early Cretaceous about 105 million years ago until the end of the Late Cretaceous, about 66 mya. Many genera are included in the clade, such as Ankylosaurus, Pinacosaurus, Euoplocephalus, and Saichania.Bienosaurus
Bienosaurus (meaning "Bien's lizard") is a genus of thyreophoran dinosaur from the Lower Jurassic (probably Sinemurian) Lower Lufeng Formation in Yunnan Province in China.Bissektipelta
Bissektipelta is a genus of herbivorous ankylosaurid dinosaur from the Upper Cretaceous of Uzbekistan. Bissektipelta is monospecific, containing only the species B. archibaldi.Chuanqilong
Chuanqilong is an extinct genus of ankylosaurid dinosaur from the Early Cretaceous of China. It is known from the type species, Chuanqilong chaoyangensis. It lived during the Aptian stage of early Cretaceous period (125 - 112 mya) and was about 4.5 meters long. Its weight is estimated at some 450 kg.Craterosaurus
Craterosaurus (meaning krater reptile or bowl reptile) was a genus of stegosaurid dinosaur. It lived during the Early Cretaceous (Valanginian to Barremian stages) around 145-136 million years ago. Its fossils were found in the Woburn Sands Formation of England. Craterosaurus may actually be a junior synonym of Regnosaurus, but only one fossil, a partial vertebra, was recovered.
The type (and only known) species is Craterosaurus pottonensis, described in 1874 by Harry Seeley. The specific name refers to the Potton bonebed. Seeley mistook the fossil, holotype SMC B.28814, for the base of a cranium. Franz Nopcsa in 1912 correctly identified it as the front part of a neural arch. Craterosaurus was placed in Stegosauria by Galton, although subsequent authors did not recognize Craterosaurus as a distinct, valid taxon.Dongyangopelta
Dongyangopelta is an extinct genus of nodosaurid ankylosaurian dinosaur known from the "middle" Cretaceous Chaochuan Formation (Albian or Cenomanian stage) of Dongyang, Zhejiang Province, China. Dongyangopelta was first named by Rongjun Chen, Wenjie Zheng, Yoichi Azuma, Masateru Shibata, Tianliang Lou, Qiang Jin and Xingsheng Jin in 2013 and the type species is Dongyangopelta yangyanensis. It differs from Zhejiangosaurus, the second nodosaurid from southeast China, in the characters of presacral rod, ilium, and femur. Donyangopelta is distinguishable from Zhejiangosaurus only on the basis of the morphology of its pelvic shield.Invictarx
Invictarx is a genus of herbivorous nodosaurid dinosaur from New Mexico dating from the early Campanian epoch of the Late Cretaceous.Mongolostegus
Mongolostegus is a genus of stegosaur from the Early Cretaceous (Aptian-Albian) of Mongolia. The type and only species is M. exspectabilis, known from a single specimen previously under the nomen nudum Wuerhosaurus mongoliensis.Nodosaurinae
Nodosaurinae is a group of ankylosaurian dinosaurs named in 1919 by Othenio Abel.Nodosaurus
Nodosaurus (meaning "knobbed lizard") is a genus of herbivorous ankylosaurian dinosaur from the Late Cretaceous, the fossils of which are found in North America.Paranthodon
Paranthodon ( pə-RAN-thə-don) is a genus of stegosaurian dinosaur that lived in what is now South Africa during the Early Cretaceous, between 139 and 131 million years ago. Discovered in 1845, it was one of the first stegosaurians found. Its only remains, a partial skull, isolated teeth, and fragments of vertebrae, were found in the Kirkwood Formation. British paleontologist Richard Owen initially identified the fragments as those of the pareiasaur Anthodon. After remaining untouched for years in the British Museum of Natural History, the partial skull was identified by South African paleontologist Robert Broom as belonging to a different genus; he named the specimen Palaeoscincus africanus. Several years later, Hungarian paleontologist Franz Nopcsa, unaware of Broom's new name, similarly concluded that it represented a new taxon, and named it Paranthodon owenii. Since Nopcsa's species name was assigned after Broom's, and Broom did not assign a new genus, both names are now synonyms of the current binomial, Paranthodon africanus. The genus name combines the Ancient Greek para (near) with the genus name Anthodon, to represent the initial referral of the remains.
In identifying the remains as those of Palaeoscincus, Broom initially classified Paranthodon as an ankylosaurian, a statement backed by the research of Coombs in the 1970s. In 1929, Nopcsa identified the taxon as a stegosaurid, with which most modern studies agree. In 1981, the genus was reviewed with modern taxonomic techniques, and found to be a valid genus of stegosaurid. A 2018 review of Paranthodon could only identify one distinguishing feature, and while that study still referred it to Stegosauria based on similarity and multiple phylogenetic analyses, no diagnostic features of the group could be identified in Paranthodon.Silvisaurus
Silvisaurus, from the Latin silva "woodland" and Greek sauros "lizard", is a nodosaurid ankylosaur from the middle Cretaceous period.Stegosauria
Stegosauria is a group of herbivorous ornithischian dinosaurs that lived during the Jurassic and early Cretaceous periods. Stegosaurian fossils have been found mostly in the Northern Hemisphere, predominantly in what is now North America, Europe, Africa, South America and Asia Their geographical origins are unclear; the earliest unequivocal stegosaurian, Huayangosaurus taibaii, lived in China.
Stegosaurians were armored dinosaurs (thyreophorans). Originally, they did not differ much from more primitive members of that group, being small, low-slung, running animals protected by armored scutes. An early evolutionary innovation was the development of tail spikes, or "thagomizers", as defensive weapons. Later species, belonging to a subgroup called the Stegosauridae, became larger, and developed long hindlimbs that no longer allowed them to run. This increased the importance of active defence by the thagomizer, which could ward off even large predators because the tail was in a higher position, pointing horizontally to the rear from the broad pelvis. Stegosaurids had complex arrays of spikes and plates running along their backs, hips and tails. Their necks became longer and their small heads became narrow, able to selectively bite off the best parts of cycads with their beaks. When these plant types declined in diversity, so did the stegosaurians, which became extinct during the first half of the Cretaceous period.
The first stegosaurian finds in the early 19th century were fragmentary. Better fossil material, of the genus Dacentrurus, was discovered in 1874 in England. Soon after, in 1877, the first nearly-complete skeleton was discovered in the United States. Professor Othniel Charles Marsh that year classified such specimens in the new genus Stegosaurus, from which the group acquired its name, and which is still by far the most famous stegosaurian. During the latter half of the twentieth century, many important Chinese finds were made, representing about half of the presently known diversity of stegosaurians.Tatisaurus
Tatisaurus is a genus of ornithischian dinosaur from the Early Jurassic from the Lower Lufeng Formation in Yunnan Province in China. Little is known as the remains are fragmentary.Texasetes
Texasetes (meaning "Texas resident") is a genus of ankylosaurian dinosaurs from the late Lower Cretaceous of North America. This poorly known genus has been recovered from the Paw Paw Formation (late Albian) near Haslet, Tarrant County, Texas, which has also produced the nodosaurid ankylosaur Pawpawsaurus. Texasetes is estimated to have been 2.5–3 m (8–10 ft) in length. It was named by Coombs in 1995.Tianzhenosaurus
Tianzhenosaurus (Tianzhen + Greek sauros="lizard") is a genus of ankylosaurid dinosaurs discovered in Tianzhen County, at Kangdailiang near Zhaojiagou Village, in Shanxi Province, China, in the Late Cretaceous Huiquanpu Formation. Thus far, a virtually complete skull and postcranial skeleton have been assigned to the genus, which is monotypic (T. youngi Pang & Cheng, 1998).
This was a medium-sized ankylosaurian, the skull measuring 28 cm (11 in) in length, with a total body length around 4 m (13 ft).
Vickaryous et al. (2004) placed Tianzhenosaurus within the Ankylosauridae, nested as the sister group to Pinacosaurus. Some authors have suggested that Tianzhenosaurus is actually a junior synonym of Saichania chulsanensis.Tsagantegia
Tsagantegia (; meaning "of Tsagan-Teg"; Tumanova, 1993) is a genus of medium-sized ankylosaurid dinosaur from the Late Cretaceous of Mongolia, during the Cenomanian stage.
The holotype specimen (GI SPS N 700/17), a complete skull, was recovered from the Bayan Shireh Formation (Cenomanian-Santonian), at the Tsagan-Teg ("White Mountain") locality, Dzun-Bayan, in the southeastern Gobi Desert, Mongolia. The genus is monotypic, including only the type species, T. longicranialis.Wuerhosaurus
Wuerhosaurus is a genus of stegosaurid dinosaur from the Early Cretaceous Period of China and Mongolia. As such, it was one of the last genera of stegosaurians known to have existed, since most others lived in the late Jurassic.