Lexovisaurus is a genus of stegosaur from mid-to-Late Jurassic Europe, 164.7 mya. Fossils of limb bones and armor fragments have been found in middle to late Jurassic-aged strata of England and France.
|Vertebrae and spike, Muséum national d'histoire naturelle, Paris|
(Hulke, 1887 [originally Omosaurus])
In the early 1880s collector Alfred Nicholson Leeds acquired a skeleton of a dinosaur excavated at a small brick pit at the hamlet of Tanholt, close to Eye, Cambridgeshire. In September 1885 the remains were shown to paleontologist Henry Woodward whose notes form the first documentation on the subject. Later it was mistakenly assumed the find had been made at the industrial brick pits at Fletton, the usual source of Leeds' specimens. In 1887 the fossil was described by John Whitaker Hulke and named as a new species of the stegosaurian Omosaurus: Omosaurus durobrivensis. The specific name referred to the old Roman town of Durobrivae. On 30 May 1892 the specimen was bought by the British Museum of Natural History.
The holotype, BMNH R1989, was found in the Peterborough Member of the Oxford Clay Formation, more especially the Kosmoceras jason biozone dating from the middle Callovian. Hulke mistakenly assumed a provenance from the younger Kimmeridge Clay Formation. It consists of a sacrum of five vertebrae, and two ilia. Other bones were referred to the species, among them two plates thought to be part of the dermal armour. However, on 22 August 1888 Othniel Charles Marsh visited Leeds' collection at Eyebury and recognised these elements as belonging to a giant fish, in 1889 by Arthur Smith Woodward named Leedsichthys. The plates are in fact part of the latter's skull roof.
In 1915 Omosaurus durobrivensis was renamed Dacentrurus durobrivensis, as the name Omosaurus had been preoccupied, which had already been indicated by Marsh in the 1870s. In 1957 the French palaeontologist Robert Hoffstetter created a separate genus for the species: Lexovisaurus. The generic name is derived from the Lexovii, a Gallic tribe in ancient times inhabiting the region of Normandy, where several stegosaurian specimens had been discovered which by Hoffstetter were referred to Lexovisaurus. While the type species remains Omosaurus durobrivensis, the combinatio nova is Lexovisaurus durobrivensis. Hofstetter also referred a much more complete stegosaurian skeleton in 1901 discovered by Leeds in the Fletton brick pit, specimen BMNH R3167 that in 1911 had been named Stegosaurus priscus. Subsequently, in 1964, Oskar Kuhn referred the nomen nudum "Omosaurus leedsi" Seeley vide Huene 1901 to Lexovisaurus as Lexovisaurus leedsi. In 1983, Peter Malcolm Galton renamed Omosaurus vetustus Huene 1910 into Lexovisaurus vetustus.
However, in 2008 Susannah Maidment and colleagues concluded that the holotype of Lexovisaurus, BMNH R1989, was undiagnostic, so they split off BMNH R3167 and the French finds naming them as a separate new genus: Loricatosaurus. This made Lexovisaurus a nomen dubium, while O. vetustus was found to be undiagnostic and declared a nomina dubium. Other workers though, combining the English material collected by Leeds due to its shared provenance, have considered Lexovisaurus a valid taxon. In the meantime, Omosaurus vetustus has been renamed Eoplophysis, although this genus is not regarded as valid. The nomen nudum "Omosaurus leedsi" (mistakenly considered a nomen dubium by Maidment et al. 2008) has since been referred to Loricatosaurus.
If Lexovisaurus is limited to the holotype, little information about it is available apart from it having a general stegosaurian build and a pelvis width of 114 centimetres. Part of the material described by Hulke was a left femur, specimen BMNH R1991, with a length of ninety-nine centimetres, indicating a body length of about five metres (16.5 ft). The Fletton and Normandy material, suggesting a body length of about six metres and a weight of two tonnes, show a combination of narrow flat plates on the back and round pointed spines that ran along the tail. A large spine was found that by Hoffstetter was placed on the shoulder, by Galton on the hip and by Maidment on the tail.
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.Callovian
In the geologic timescale, the Callovian is an age and stage in the Middle Jurassic, lasting between 166.1 ± 4.0 Ma (million years ago) and 163.5 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the Oxfordian.Cetiosauriscus
Cetiosauriscus ( SEE-tee-oh-SOR-iss-kəs) is a genus of sauropod dinosaur that lived between 166 and 164 million years ago during the Callovian (Middle Jurassic Period) in what is now England. A herbivore, Cetiosauriscus had—for sauropod standards—a moderately long tail, and longer forelimbs, making them as long as its hindlimbs. It has been estimated as about 15 m (49 ft) long and between 4 and 10 t (3.9 and 9.8 long tons; 4.4 and 11.0 short tons) in weight.
The only known fossil that was later named Cetiosauriscus includes most of the rear half of a skeleton as well as a hindlimb (NHMUK R3078). Found in Cambridgeshire in the 1890s, it was described by Arthur Smith Woodward in 1905 as a new specimen of the species Cetiosaurus leedsi. This was changed in 1927, when Friedrich von Huene found NHMUK R3078 and the C. leedsi type specimen to be too different from Cetiosaurus, warranting its own genus, which he named Cetiosauriscus, meaning "Cetiosaurus-like". Cetiosauriscus leedsi was referred to the sauropod family Diplodocidae because of similarities in the tail and foot, and had the dubious or intermediate species "Cetiosauriscus" greppini, "C." longus, and "C." glymptonensis assigned to it. In 1980, Alan Charig named a new species of Cetiosauriscus for NHMUK R3078 because of the lack of comparable material to the type of C. leedsi; this species was named Cetiosauriscus stewarti. Because of the poor state of preservation of the Cetiosauriscus leedsi fossil, Charig sent a petition to the International Commission on Zoological Nomenclature to instead make C. stewarti the type species. Cetiosauriscus stewarti became the oldest confirmed diplodocid until a phylogenetic analysis published in 2003 instead found the species to belong to Mamenchisauridae, and followed by studies in 2005 and 2015 that found it outside Neosauropoda, while not a mamenchisaurid proper.
Cetiosauriscus was found in the marine deposits of the Oxford Clay Formation alongside many different invertebrate groups, marine ichthyosaurs, plesiosaurs and crocodylians, a single pterosaur, and various dinosaurs: the ankylosaur Sarcolestes, the stegosaurs Lexovisaurus and Loricatosaurus, the ornithopod Callovosaurus, as well as some unnamed taxa. The theropods Eustreptospondylus, Metriacanthosaurus and Megalosaurus are known from the formation, although probably not from the same level as Cetiosauriscus.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.Dacentrurus
Dacentrurus (meaning "tail full of points"), originally known as Omosaurus, was a large stegosaur of the Late Jurassic Period (154 - 150 mya) of Europe. Its type species, Omosaurus armatus, was named in 1875, based on a skeleton found in the Kimmeridge Clay of England. In 1902 the genus was renamed Dacentrurus because the name Omosaurus had already been used for a crocodylian. After 1875, half a dozen other species would be named but perhaps only Dacentrurus armatus is valid.
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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.Loricatosaurus
Loricatosaurus (meaning "armored lizard") is a dinosaur of Stegosauridae family from Callovian-age (Middle Jurassic) rocks of England and France.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.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.Oxford Clay
The Oxford Clay is a Jurassic marine sedimentary rock formation underlying much of southeast England, from as far west as Dorset and as far north as Yorkshire. The Oxford Clay Formation dates to the Jurassic, specifically, the Callovian and Oxfordian ages, and comprises two main facies. The lower facies comprises the Peterborough Member, a fossiliferous organic-rich mudstone. This facies and its rocks are commonly known as lower Oxford Clay. The upper facies comprises the middle Oxford Clay, the Stewartby Member, and the upper Oxford Clay, the Weymouth Member. The upper facies is a fossil poor assemblage of calcareous mudstones.
Oxford Clay appears at the surface around Oxford, Peterborough and Weymouth and is exposed in many quarries around these areas. The top of the Lower Oxford Clay shows a lithological change, where fissile shale changes to grey mudstone. The Middle and Upper Oxford Clays differ slightly, as they are separated by an argillaceous limestone in the South Midlands.
The Callovo-Oxfordian Clay also occurs in the Paris Basin (France) and it is a potential host formation to dispose of high-level radioactive waste in France.Silvisaurus
Silvisaurus, from the Latin silva "woodland" and Greek sauros "lizard", is a nodosaurid ankylosaur from the middle Cretaceous period.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.
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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.