Tuojiangosaurus

Last updated

Tuojiangosaurus
Temporal range: Late Jurassic, 163.5–157.3  Ma
Natural History Museum Tuojiangosaurus.jpg
Mounted skeleton (NHMUK PV R 12158) at the Natural History Museum, London
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Ornithischia
Clade: Thyreophora
Clade: Stegosauria
Genus: Tuojiangosaurus
Dong et al., 1977
Species:
T. multispinus
Binomial name
Tuojiangosaurus multispinus
Dong et al., 1977

Tuojiangosaurus (meaning "Tuo River lizard") is a genus of herbivorous stegosaurian dinosaur from the Late Jurassic Period, recovered from the Upper Shaximiao Formation of what is now Sichuan Province in China.

Contents

Description

Size comparison Tuojiangosaurus Scale.svg
Size comparison

Tuojiangosaurus was a large stegosaur, reaching 6.5 metres (21 ft) in length and 2.8 metric tons (3.1 short tons) in body mass. [1] Physically similar to the North American Stegosaurus , Tuojiangosaurus is the best understood of the Chinese stegosaurs. [2]

In 1977, Dong provided a diagnosis but this largely consisted of traits shared with other stegosaurus. In 1990, Peter Malcolm Galton pointed out an autapomorphy: the spines of the vertebrae of the tail base possess spines with bony skirts running from their front to the sides. [3]

Tuojiangosaurus has the typical narrow and low head, bulky body, and low teeth of other stegosaurids. The limbs, especially the arms, are rather short. [4] There are at least twenty-five dentary teeth. The teeth have a thick base, cingulum, merging at the inside into a triangular vertical median ridge. The dorsal vertebrae have tall neural arches. The shoulder blade has a rectangular acromion. [5]

Restoration Tuojiangosaurus multispinus life restoration.jpg
Restoration
Reconstructed skeleton Tuojiangosaurus multispinus mount img1.jpg
Reconstructed skeleton

Like Kentrosaurus , Tuojiangosaurus had two rows of plates along the spine, which became taller over the hip region. Those at the neck and front trunk were rounded or pear-shaped; the plates at the rear back became more triangular and pointed. All plates have a thickened central section, as if they were modified spikes. [5] Dong estimated there were about seventeen pairs of plates and spikes. Tuojiangosaurus had at least two outward-pointing, rather robust, spikes on each side of the end of the tail, angled at approximately 45 degrees to the vertical. In stegosauridae, this spike arrangement has become affectionately known as the "thagomizer". [2] Dong thought it were possible that there were four pairs of spikes. Paul, based on " Chungkingosaurus sp. 3" specimen CV 00208, interpreted the thagomizer as a "pin-cushion array", with two vertical pairs of thick spikes and a third pair of narrow spikes pointing to behind. [4]

Discovery

Skull of the mount Tuojiangosaurus multispinus.003 - Natural History Museum of London.JPG
Skull of the mount

In 1974, during construction of the Wujiaba dam in Zigong, Sichuan, the remains of a stegosaurian were found.

The type and only species of Tuojiangosaurus, Tuojiangosaurus multispinus, was named and described in 1977 (exactly a hundred years after the naming of Stegosaurus by Othniel Charles Marsh) by Dong Zhiming, Zhou Shiwu, Li Xuanmin and Chang Yijong. The generic name is derived from the River (jiāng) Tuo. The specific name is derived from Latin multus, "many", and spina, "spine". [6]

A mounted skeleton at the Beijing Museum of Natural History, confronting a Yangchuanosaurus Tuojiangosaurus at the Beijing Museum of Natural History.jpg
A mounted skeleton at the Beijing Museum of Natural History, confronting a Yangchuanosaurus

The holotype, CV 209, was found in a layer of the Upper Shaximiao Formation, dating from the Oxfordian-Kimmeridgian. It consists of a rather complete skeleton that however lacks parts of the skull, lower jaws, tail and limbs. In 1977, it represented the most complete stegosaurian skeleton found in Asia. The paratype was specimen CV 210, a sacrum. [6] Subsequently, more material has been referred, including juveniles. This complemented the holotype with elements of the skull, especially the braincase, and the lower jaws.

A mounted skeleton of Tuojiangosaurus multispinus is on display at the Municipal Museum of Chongqing. In addition, a mounted cast (NHMUK PV R 12158) is on display at the Natural History Museum, in London. Another mount is displayed in the Beijing Museum of Natural History in a conflict with Yangchuanosaurus . A cast of the original fossilised dinosaur skeleton, found at Wujiaba Quarry 1977 is also on display at Bolton Museum, United Kingdom.

Classification

Tuojiangosaurus in Shandong Museum Shan Dong Bo Wu Guan Zhan Shi Kong Long Zhi Yi .jpg
Tuojiangosaurus in Shandong Museum

Tuojiangosaurus was by Dong placed in Stegosauridae in 1977, more precisely in the Stegosaurinae. [6] In 2004, a cladistic analysis by Galton recovered Tuojiangosaurus in a rather derived position, as a sister species of Chialingosaurus . [5] An analysis by Octávio Mateus, Maidment, and Nicolai Christiansen, published in 2009, found that Tuojiangosaurus fell outside of Stegosauridae, though its exact position in Stegosauria (either as an early branching member of the group or a later branching species closer to stegosaurids) was uncertain due to the relatively fragmentary nature of the remains. [7] A more comprehensive analysis by Raven and Maidment in 2017 found that it grouped with Huayangosaurus and its relatives. [8]

Paleobiology

Tuojiangosaurus ate low-lying, ground vegetation. [9] Paul suggested that Chialingosaurus and Chungkingosaurus were in fact the juveniles of Tuojiangosaurus. [4]

See also

Notes

  1. Paul, G. S. (2010). The Princeton Field Guide to Dinosaurs. Princeton University Press. pp.  221. ISBN   978-0-691-13720-9.
  2. 1 2 Benton, Michael J. (2012). Prehistoric Life. Edinburgh, Scotland: Dorling Kindersley. pp. 274–275. ISBN   978-0-7566-9910-9.
  3. Galton, P.M., 1990, "Stegosauria", in: D.B. Weishampel, P. Dodson, & H. Osmólska (eds.), The Dinosauria. University of California Press, pp. 435-455
  4. 1 2 3 Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 221
  5. 1 2 3 Galton, P.M., and P. Upchurch, 2004, "Stegosauria", pp. 343-362 in: D.B. Weishampel, P. Dodson, and H. Osmolska (eds.), The Dinosauria, 2nd Edition. University of California Press, Berkeley, CA
  6. 1 2 3 Z. Dong, X. Li, S. Zhou and Y. Zhang, 1977, "On the stegosaurian remains from Zigong (Tzekung), Szechuan province", Vertebrata PalAsiatica15(4): 307-312
  7. Mateus, Maidment and Christiansen (2009). "A new long-necked ‘sauropod-mimic’ stegosaur and the evolution of the plated dinosaurs", Proc Biol Sci. 2009 May 22; 276(1663): 1815–1821.
  8. Raven, T.j.; Maidment, S.C.R. (2017). "A new phylogeny of Stegosauria (Dinosauria, Ornithischia)" (PDF). Palaeontology. 2017 (3): 401–408. Bibcode:2017Palgy..60..401R. doi:10.1111/pala.12291. hdl: 10044/1/45349 .
  9. Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 156. ISBN   1-84028-152-9.

Related Research Articles

<i>Stegosaurus</i> Thyreophoran stegosaurid dinosaur genus from Late Jurassic period

Stegosaurus is a genus of herbivorous, four-legged, armored dinosaur from the Late Jurassic, characterized by the distinctive kite-shaped upright plates along their backs and spikes on their tails. Fossils of the genus have been found in the western United States and in Portugal, where they are found in Kimmeridgian- to Tithonian-aged strata, dating to between 155 and 145 million years ago. Of the species that have been classified in the upper Morrison Formation of the western US, only three are universally recognized: S. stenops, S. ungulatus and S. sulcatus. The remains of over 80 individual animals of this genus have been found. Stegosaurus would have lived alongside dinosaurs such as Apatosaurus, Diplodocus, Camarasaurus and Allosaurus, the latter of which may have preyed on it.

<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>Hesperosaurus</i> Extinct genus of dinosaurs

Hesperosaurus is a herbivorous stegosaurian dinosaur from the Kimmeridgian age of the Jurassic period, approximately 156 million years ago.

<i>Dacentrurus</i> Extinct species of reptile

Dacentrurus, originally known as Omosaurus, is a genus of stegosaurian dinosaur from the Late Jurassic and perhaps Early Cretaceous of Europe.

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

Chialingosaurus is a genus of herbivorous stegosaurian dinosaur similar to Kentrosaurus from the Upper Shaximiao Formation, Late Jurassic beds in Sichuan Province in China. Its age makes it one of the oldest species of stegosaurs, living about 160 million years ago. Since it was an herbivore, scientists think that Chialingosaurus probably ate ferns and cycads, which were plentiful during the period when Chialingosaurus was alive.

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

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.

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

Huayangosaurus is a genus of stegosaurian dinosaur from the Middle Jurassic of China. The name derives from "Huayang" (華陽), an alternate name for Sichuan, and "saurus", meaning "lizard". It lived during the Bathonian to Callovian stages, around 165 million years ago, some 20 million years before its famous relative, Stegosaurus appeared in North America. At only approximately 4 metres (13 ft) long, it was also much smaller than its famous cousin. Found in the Lower Shaximiao Formation, Huayangosaurus shared the local Middle Jurassic landscape with the sauropods Shunosaurus, Datousaurus, Omeisaurus and Protognathosaurus, the ornithopod Xiaosaurus and the carnivorous Gasosaurus.

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

Lexovisaurus is a genus of stegosaur from mid-to-Late Jurassic Europe, 165.7-164.7 mya. Fossils of limb bones and armor fragments have been found in middle to late Jurassic-aged strata of England and France.

<i>Paranthodon</i> Stegosaurian dinosaur genus from Early Cretaceous South Africa

Paranthodon 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.

<span class="mw-page-title-main">Stegosauria</span> Extinct clade of dinosaurs

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, Africa and possibly South America. Their geographical origins are unclear; the earliest unequivocal stegosaurian, Bashanosaurus primitivus, was found in the Bathonian Shaximiao Formation of China.

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

Chungkingosaurus, meaning "Chongqing Lizard", is a genus of herbivorous dinosaur from the Late Jurassic Upper Shaximiao Formation in what is now China. It is a member of the Stegosauria.

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

Gigantspinosaurus is a genus of herbivorous ornithischian dinosaur from the Late Jurassic. It was a stegosaur found in China.

Monkonosaurus is a dubious genus of herbivorous stegosaurian dinosaur from the Late Jurassic/Early Cretaceous-aged Loe-ein Formation of Tibet. Some sources place it as alive during the Oxfordian - Albian stages, around 163 - 100 million years ago, although Monkonosaurus was probably only alive during the Late Jurassic, making it among the earliest known stegosaurs along with Chungkingosaurus and Bashanosaurus.

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

Yingshanosaurus is a genus of stegosaurian dinosaur from the Late Jurassic, around 155 million years ago. It was a herbivore that lived in what is now China. The type species is Yingshanosaurus jichuanensis.

<i>Hypsirhophus</i> Genus of dinosaurs

Hypsirhophus is a genus of stegosaurian dinosaurs. It contains a single species, Hypsirhophus discurus, which is known only from a fragmentary specimen. The fossil consists of partial vertebrae from the back, three from the tail, and a piece of rib.

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

Loricatosaurus is a Stegosaurid genus from Callovian-age rocks of England and France.

<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. Some researchers consider this taxon to be a junior synonym of Dacentrurus.

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

Alcovasaurus, alternatively known as Miragaia longispinus, is a genus of herbivorous stegosaurian dinosaur that lived in the Late Jurassic. It was found in the Morrison Formation of Natrona County, Wyoming, United States. The type species is Stegosaurus longispinus, later given the genus Alcovasaurus.

<span class="mw-page-title-main">Timeline of stegosaur research</span>

This timeline of stegosaur research is a chronological listing of events in the history of paleontology focused on the stegosaurs, the iconic plate-backed, spike-tailed herbivorous eurypod dinosaurs that predominated during the Jurassic period. The first scientifically documented stegosaur remains were recovered from Early Cretaceous strata in England during the mid-19th century. However, they would not be recognized as a distinct group of dinosaurs until Othniel Charles Marsh described the new genus and species Stegosaurus armatus in 1877, which he regarded as the founding member of the Stegosauria. This new taxon originally included all armored dinosaurs. It was not until 1927 that Alfred Sherwood Romer implemented the modern use of the name Stegosauria as specifically pertaining to the plate-backed and spike-tailed dinosaurs.

<i>Bashanosaurus</i> Extinct genus of stegosaurian dinosaurs

Bashanosaurus is an extinct genus of stegosaurian dinosaur from the Middle Jurassic Shaximiao Formation of Yunyang County, China. The genus contains a single species, Bashanosaurus primitivus, known from incomplete skeletons belonging to three individuals. It is one of the basalmost stegosaurs, as well as one of the oldest known stegosaurs, along with Adratiklit, Isaberrysaura, and Thyreosaurus.

References