Shidaisaurus

Last updated

Shidaisaurus
Temporal range: Early Aalenian, 174  Ma
O
S
D
C
P
T
J
K
Pg
N
Shidaisaurus.png
Life restoration
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Family: Metriacanthosauridae
Subfamily: Metriacanthosaurinae
Genus: Shidaisaurus
Species:
S. jinae
Binomial name
Shidaisaurus jinae
Wu et al., 2009

Shidaisaurus is a genus of metriacanthosaurid dinosaur. [1] Its fossil was found in early Middle Jurassic-age rocks of the Chuanjie Formation in Yunnan, China. It is known from a partial skeleton, holotype DML-LCA 9701-IV, found at the bottom of an assemblage of nine dinosaur individuals, lacking most of the tail vertebrae, ribs, pectoral girdle, and limb bones. Shidaisaurus was described in 2009 by Wu and colleagues. The type species is Shidaisaurus jinae. [2] Generic name and specific name in combination refer to the Jin-Shidai ("Golden Age") Company that oversaw excavation and inspection of the Jurassic World Park near the site.

Contents

Description

Based on the known remains, Shidaisaurus was a medium-sized, predatory theropod much like its kin. Its skull bears many similarities to its close relative Sinraptor . Most of the posterior portion of the skull is preserved, including the frontals, parietals, nasals, teeth, and the braincase. Many elements of its skull resemble Sinraptor the most, such as the outline of the parietal bones. Most of the major portions of the braincase are preserved. The paroccipital process faces down and to the sides, much like other allosauroids. However, they do not project downward nearly as much as seen in Allosaurus , possibly owing to the animal's status as a very basal member. Certain aspects of Shidaisaurus braincase also resemble Sinraptor the most, such as the outline of the supraoccipital bones.

Shidaisaurus possesses a unique combination of features in the skeleton that distinguish it from other theropods (its autapomorphies). For example, the supraoccipital bones are prevented from entering the foramen magnum by the exoccipitals. Its second cervical (neck) vertebra, the axis, has a tall and sharply pointing epipophysis. Between the epipophysis and neural spine is a thin lamina that appears broader than it does in other theropods with the same structure. The length of its pubis, when measured from below the front to behind and above, is equal to the height of its iliac blade. It also lacks a ventral notch distal to the obturator process on its ischium

The postcranial skeleton shows many features shared with other tetanurans. Its neural spines are tall and swept slightly posterodorsally like in related allosauroids. Only two of the neck vertebrae are known in detail since the rest of the cervicals were obscured by the sauropod skeleton. Based on the condition in Sinraptor and Yangchuanosaurus, Shidaisaurus is thought to have had a total of 25 vertebrae before the sacrum, consisting of 9 cervicals and 13 dorsals. A total of 4 sacral vertebrae are present, although the tail is incomplete, making a precise count of its caudals impossible.

Many of its dorsal vertebrae lack the pleurocels seen in the dorsal vertebrae of related animals, owing to its primitive nature. This theropod according to Gregory Paul was about 6 metres (20 ft) long and it weighed around 700 kilograms (1,500 lb). [3] In 2016 another estimation listed it higher at 7.1 meters (23.3 feet) long and 950 kilograms (2,094 lbs). [4] It is the oldest Allosauroid known to date.

Classification

Orionides

Megalosauroidea

Avetheropoda
Coelurosauria

Lourinhanosaurus

Other coelurosaurians

Allosauroidea
Allosauria

Allosauridae

Carcharodontosauria

Neovenatoridae

Carcharodontosauridae

Metriacanthosauridae

Yangchuanosaurus zigongensis

CV 00214

Yangchuanosaurus shangyouensis

Metriacanthosaurinae

Shidaisaurus

Metriacanthosaurus

"Sinraptor" hepingensis

Sinraptor dongi

Siamotyrannus


Related Research Articles

<i>Gallimimus</i> Ornithomimid dinosaur genus from the Late Cretaceous Period

Gallimimus is a genus of theropod dinosaur that lived in what is now Mongolia during the Late Cretaceous period, about seventy million years ago (mya). Several fossils in various stages of growth were discovered by Polish-Mongolian expeditions in the Gobi Desert of Mongolia during the 1960s; a large skeleton discovered in this region was made the holotype specimen of the new genus and species Gallimimus bullatus in 1972. The generic name means "chicken mimic", referring to the similarities between its neck vertebrae and those of the Galliformes. The specific name is derived from bulla, a golden capsule worn by Roman youth, in reference to a bulbous structure at the base of the skull of Gallimimus. At the time it was named, the fossils of Gallimimus represented the most complete and best preserved ornithomimid material yet discovered, and the genus remains one of the best known members of the group.

<i>Kentrosaurus</i> Extinct genus of dinosaurs from late Jurassic in Lindi Region, Tanzania

Kentrosaurus is a genus of stegosaurid dinosaur from the Late Jurassic in Lindi Region of Tanzania. The type species is K. aethiopicus, named and described by German palaeontologist Edwin Hennig in 1915. Often thought to be a "primitive" member of the Stegosauria, several recent cladistic analyses find it as more derived than many other stegosaurs, and a close relative of Stegosaurus from the North American Morrison Formation within the Stegosauridae.

<i>Amargasaurus</i> Dicraeosaurid sauropod dinosaur genus from the Early Cretaceous period

Amargasaurus is a genus of sauropod dinosaur from the Early Cretaceous epoch of what is now Argentina. The only known skeleton was discovered in 1984 and is virtually complete, including a fragmentary skull, making Amargasaurus one of the best-known sauropods of its epoch. Amargasaurus was first described in 1991 and contains a single known species, Amargasaurus cazaui. It was a large animal, but small for a sauropod, reaching 9 to 13 meters in length. Most distinctively, it sported two parallel rows of tall spines down its neck and back, taller than in any other known sauropod. In life, these spines could have stuck out of the body as solitary structures that supported a keratinous sheath. An alternate hypothesis, now more favored, postulates that they could have formed a scaffold supporting a skin sail. They might have been used for display, combat, or defense.

<i>Monolophosaurus</i> Extinct genus of dinosaurs

Monolophosaurus is an extinct genus of tetanuran theropod dinosaur from the Middle Jurassic Shishugou Formation in what is now Xinjiang, China. It was named for the single crest on top of its skull. Monolophosaurus was a mid-sized theropod at about 5–5.5 metres (16–18 ft) long and weighed 475 kilograms (1,047 lb).

<span class="mw-page-title-main">Metriacanthosauridae</span> Extinct family of dinosaurs

Metriacanthosauridae is an extinct family of allosauroid theropod dinosaurs that lived from the Middle Jurassic to the Early Cretaceous. When broken down into its Greek roots, it means "moderately-spined lizards". The family is split into two subgroups: Metriacanthosaurinae, which includes dinosaurs closely related to Metriacanthosaurus, and another group composed of the close relatives of Yangchuanosaurus. Metriacanthosaurids are considered carnosaurs, belonging to the Allosauroidea superfamily. The group includes species of large range in body size. Of their physical traits, most notable are their neural spines. The records of the group are mostly confined to Asia, though Metriacanthosaurus is known from Europe. Metriacanthosauridae is used as a senior synonym of Sinraptoridae.

<i>Klamelisaurus</i> Extinct genus of dinosaurs

Klamelisaurus is a genus of herbivorous sauropod dinosaur from the Middle Jurassic Shishugou Formation of China. The type species is Klamelisaurus gobiensis, which was named by Zhao Xijin in 1993, based on a partial skeleton discovered in 1982 near the abandoned town of Jiangjunmiao. Zhao described Klamelisaurus as the only member of a new subfamily, Klamelisaurinae, among the now-defunct primitive sauropod order Bothrosauropodoidea. Since Zhao's description, Klamelisaurus received limited attention from researchers until Andrew Moore and colleagues redescribed it in 2020.

<i>Qianosuchus</i> Extinct genus of reptiles

Qianosuchus is an extinct genus of aquatic poposauroid archosaur from the middle Triassic (Anisian) Guanling Formation of Pan County, China. It is represented by two nearly complete skeletons and a crushed skull preserved in the limestone. Qianosuchus was at least 3 metres long, and had several skeletal adaptations which indicate a semi-marine lifestyle, similar to modern-day saltwater crocodiles. These adaptations have not been seen in any other archosaur from the Triassic.

<span class="mw-page-title-main">Apatosaurinae</span> Extinct subfamily of dinosaurs

Apatosaurinae is a subfamily of diplodocid sauropods, an extinct group of large, quadrupedal dinosaurs, the other subfamily in Diplodocidae being Diplodocinae. Apatosaurines are distinguished by their more robust, stocky builds and shorter necks proportionally to the rest of their bodies. Several fairly complete specimens are known, giving a comprehensive view of apatosaurine anatomy.

<i>Miragaia longicollum</i> Extinct species of dinosaur

Miragaia is a long-necked stegosaurid dinosaur. Its fossils have been found in Upper Jurassic rocks in Portugal and possibly also Wyoming, United States. Miragaia has the longest neck known for any stegosaurian, which included at least seventeen vertebrae.

<i>Spinophorosaurus</i> Middle Jurassic genus of sauropod dinosaur

Spinophorosaurus is a genus of sauropod dinosaur that lived in what is now Niger during the Middle Jurassic period. The first two specimens were excavated in the 2000s by German and Spanish teams under difficult conditions. The skeletons were brought to Europe and digitally replicated, making Spinophorosaurus the first sauropod to have its skeleton 3D printed, and were to be returned to Niger in the future. Together, the two specimens represented most of the skeleton of the genus, and one of the most completely known basal sauropods of its time and place. The first skeleton was made the holotype specimen of the new genus and species Spinophorosaurus nigerensis in 2009; the generic name refers to what was initially thought to be spiked osteoderms, and the specific name refers to where it was found. A juvenile sauropod from the same area was later assigned to the genus.

<i>Leshansaurus</i> Extinct genus of dinosaurs

Leshansaurus is a genus of theropod dinosaur from the Late Jurassic Shaximiao Formation of what is now China. It was described in 2009 by a team of Chinese paleontologists. The type species is Leshansaurus qianweiensis. Fossils of Leshansaurus were discovered in strata from the Shangshaximiao Formation, a formation rich in dinosaur fossils. Li et al. referred this taxon to Sinraptoridae – a group of carnosaurian theropods, but it may belong to Megalosauridae instead.

<i>Sarahsaurus</i> Extinct genus of dinosaurs

Sarahsaurus is a genus of basal sauropodomorph dinosaur which lived during the Early Jurassic period in what is now northeastern Arizona, United States.

<i>Jesairosaurus</i> Extinct genus of reptiles

Jesairosaurus is an extinct genus of early archosauromorph reptile known from the Illizi Province of Algeria. It is known from a single species, Jesairosaurus lehmani. Although a potential relative of the long-necked tanystropheids, this lightly-built reptile could instead be characterized by its relatively short neck as well as various skull features.

<i>Ichthyovenator</i> Genus of dinosaur

Ichthyovenator is a genus of spinosaurid dinosaur that lived in what is now Laos, sometime between 125 and 113 million years ago, during the Aptian stage of the Early Cretaceous period. It is known from fossils collected from the Grès supérieurs Formation of the Savannakhet Basin, the first of which were found in 2010, consisting of a partial skeleton without the skull or limbs. This specimen became the holotype of the new genus and species Ichthyovenator laosensis, and was described by palaeontologist Ronan Allain and colleagues in 2012. The generic name, meaning "fish hunter", refers to its assumed piscivorous lifestyle, while the specific name alludes to the country of Laos. In 2014, it was announced that more remains from the dig site had been recovered; these fossils included teeth, more vertebrae (backbones) and a pubic bone from the same individual.

This glossary explains technical terms commonly employed in the description of dinosaur body fossils. Besides dinosaur-specific terms, it covers terms with wider usage, when these are of central importance in the study of dinosaurs or when their discussion in the context of dinosaurs is beneficial. The glossary does not cover ichnological and bone histological terms, nor does it cover measurements.

<i>Dracoraptor</i> Genus of reptiles (fossil)

Dracoraptor is a genus of coelophysoid dinosaur that lived during the Hettangian stage of the Early Jurassic Period of what is now Wales dated at 201.3 ± 0.2 million years old.

<i>Murusraptor</i> Extinct genus of dinosaurs

Murusraptor is a genus of carnivorous megaraptoran theropod dinosaur from the Sierra Barrosa Formation, part of the Neuquén Group of Patagonia, in Argentina, South America. It is known from a single specimen that consists of a partial skull, ribs, partial pelvis, leg and other assorted skeletal elements.

<i>Xingxiulong</i> Extinct genus of reptiles

Xingxiulong is a genus of bipedal sauropodiform from the Early Jurassic of China. It contains a single species, X. chengi, described by Wang et al. in 2017 from three specimens, two adults and an immature individual, that collectively constitute a mostly complete skeleton. Adults of the genus measured 4–5 metres (13–16 ft) long and 1–1.5 metres tall. Phylogenetic analysis suggests that Xingxiulong is most closely related to its contemporary Jingshanosaurus, although an alternative position outside of both the Sauropodiformes and Massospondylidae is also plausible.

<i>Gnathovorax</i> Species of dinosaur

Gnathovorax is a genus of herrerasaurid saurischian dinosaur from the Santa Maria Formation in Rio Grande do Sul, Brazil. The type and only species is Gnathovorax cabreirai, described by Pacheco et al. in 2019.

<i>Lusovenator</i> Extinct genus of dinosaurs

Lusovenator is a genus of carcharodontosaurian theropod dinosaur, from the Late Jurassic (Kimmeridgian) Praia de Amoreira Porto-Novo Member and the Late Jurassic-Early Cretaceous (Tithonian-Berriasian) Assenta Member of the Lourinhã Formation in present-day Portugal. It includes one species, Lusovenator santosi.

References

  1. Carrano, M. T.; Benson, R. B. J.; Sampson, S. D. (2012). "The phylogeny of Tetanurae (Dinosauria: Theropoda)". Journal of Systematic Palaeontology. 10 (2): 211–300. doi:10.1080/14772019.2011.630927 . Retrieved 9 June 2017.
  2. Wu X.; Currie, P.J.; Dong Z.; Pan S.; Wang T. (2009). "A new theropod dinosaur from the Middle Jurassic of Lufeng, Yunnan, China". Acta Geologica Sinica. 83 (1): 9–24. doi:10.1111/j.1755-6724.2009.00002.x.
  3. Paul, G. S. (2010). The Princeton Field Guide to Dinosaurs . Princeton University Press, p. 85.
  4. Molina-Peréz & Larramendi (2016). Récords y curiosidades de los dinosaurios Terópodos y otros dinosauromorfos. Barcelona, Spain: Larousse. p. 260. ISBN   9780565094973.