Wuerhosaurus

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Wuerhosaurus
Temporal range:
Early Cretaceous, 132–113  Ma
Wuerhosaurus by ABelov2014.jpg
Restoration of W. homheni with low plates
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Ornithischia
Clade: Thyreophora
Clade: Stegosauria
Family: Stegosauridae
Subfamily: Stegosaurinae
Genus: Wuerhosaurus
Dong, 1973 [1]
Type species
Wuerhosaurus homheni
Dong, 1973 [1]
Species
  • W. homheniDong, 1973 [1]
  • W. ordosensisDong, 1993 [2]
Synonyms
  • Stegosaurus homheni(Dong, 1973) Maidment et al., 2008

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. [3]

Contents

Discovery and species

Plate of W. homheni, Paleozoological Museum of China Wuerhosaurus-Paleozoological Museum of China.jpg
Plate of W. homheni, Paleozoological Museum of China

Wuerhosaurus homheni is the type species, described by Dong Zhiming in 1973 from the Tugulu Group in Xinjiang, western China. The generic name is derived from the city of Wuerho. Three separate localities in the Wuerho Valley were discovered to contain material from the new stegosaur: 64043-5, 64043 and 64045. [1] The remains consisted of the holotype, Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) V.4006, a skull-less fragmentary skeleton, and the paratype IVPP V.4007. [4] Holotype material includes a mostly complete pelvis and sacrum lacking the ischium, the first caudal vertebrae, two dorsal vertebrae, a scapulocoracoid, humerus and phalanx, as well as two dermal plates. Three posterior caudal vertebrae from the tail and a partial ulna of a second individual form the paratype, and Dong referred a partial ischium from a third locality to Wuerhosaurus. [1]

A smaller stegosaur from the Ejinhoro Formation in the Ordos Basin in Inner Mongolia was found in 1988. When the specimen (IVPP V.6877) was described by Dong in 1993, it was named W. ordosensis, as it was from a similar age and had a similar anatomy. The holotype of the species includes a nearly complete torso, consisting of three cervical vertebrae, all eleven dorsal vertebrae (with attached ribs), a complete sacrum with a right ilium, and the first five caudal vertebrae, all articulated. An additional dorsal vertebra and dermal plate were referred to the taxon when it was named. [2] In 2014 Ulansky named a new species of Wuerhosaurus, "W. mongoliensis" for vertebrae and pelvic material, but the name is an invalid nomen nudum . [5] It was formally described as Mongolostegus in 2018.

Description

Wuerhosaurus homheni was probably a broad-bodied animal, reaching 7 metres (23 ft) in length and 4 metric tons (4.4 short tons) in body mass. [6] Only a few scattered bones have been found, making a full restoration difficult. [3] Its dorsal plates were at first thought to have been much rounder or flatter than other stegosaurids, [7] but Maidment established this was an illusion caused by breakage: their actual form is unknown. W. homheni had a pelvis of which the front of the ilia strongly flared outwards indicating a very broad belly. The neural spines on the tail base were exceptionally tall.

In contrast, W. ordosensis was much smaller, estimated by Paul to have been 5 m (16 ft) long and weigh 1.2 metric tons (1.3 short tons). It had a relatively long neck with a broad pelvis, but the neural spines are shorter. [6]

Classification

Phylogeny

Wuerhosaurus is one of the most derived stegosaurians, being closely related to either Dacentrurus and Hesperosaurus, or Hesperosaurus and Stegosaurus, depending on phylogenetic analysis. Carpenter et al. (2001 [8] ) recovered Wuerhosaurus in the former relationship, close to Hesperosaurus and Dacentrurus as basal in Stegosauridae. Wuerhosaurus was recovered in a different position by Escaso et al. (2007 [9] ), still related to Hesperosaurus, but basal to a clade of Lexovisaurus and Stegosaurus. Maidment et al. (2008 [10] ) recovered a different placement with Wuerhosaurus as being in a clade of taxa in derived Stegosaurinae, most closely related to Hesperosaurus and then Stegosaurus. [10] More recently, Maidment (2017 [11] ) elaborated upon her earlier analyses, and instead resolved Wuerhosaurus as closest to Stegosaurus, with Hesperosaurus being more closely related to Miragaia . These results are shown below. [11]

Restoration of W. homheni with tall plates Wuerhosaurus homheni.png
Restoration of W. homheni with tall plates
Stegosauria

Synonymy with Stegosaurus

Maidment and colleagues proposed in 2008 that Wuerhosaurus was a junior synonym of Stegosaurus, with W. homheni being renamed Stegosaurus homheni, and W. ordosensis being a dubious taxon. W. homheni was synonymized because the holotype that could be located was similar to Stegosaurus, and because of its phylogenetic position. Wuerhosaurus placed between Stegosaurus and Hesperosaurus , the latter being considered a species of Stegosaurus because of its age, location, and anatomy. Since Wuerhosaurus placed between two possible Stegosaurus species, Maidment et al. synonymized the taxon as well. Wuerhosaurus ordosensis was considered to be a nomen dubium because the holotype could not be found in the IVPP collections. The original description did not mention any valid diagnostic traits, and no other description provided features either, so Maidment et al. considered the taxon undiagnostic. [10] This opinion has been contested, however, by Carpenter (2010 [12] ). He discussed how the diagnoses and features used by Maidment et al. were inconsistent and generalized, with Wuerhosaurus homheni bearing numerous differences. As such, Carpenter advocated for the separation of both Hesperosaurus and Wuerhosaurus from Stegosaurus, and the separation of the different Stegosaurus species from S. armatus. [12]

Paleobiology

Wuerhosaurus was lower to the ground than most other stegosaurids; scientists believe that this was an adaptation to let it feed on low-growing vegetation. Wuerhosaurus, like other stegosaurids, perhaps had a thagomizer on the end of its tail, like that of Stegosaurus which featured four bony spikes that would most likely have been used for self-defense. A single spike was found but was seen by Dong as being positioned on the shoulder.

Paleoecology

The type species, W. homheni, is known from the Tugulu Group, while W. ordosensis was found in the Ejinhoro Formation. The approximate age of Wuerhosaurus is 130 mya, based on the approximate dating of the Tsaganstabian fauna, and thus the stegosaur would have lived in the Hauterivian era, which is roughly coeval with the Wealden group, from which other stegosaur material has been found. [13] Stegosaur footprints from the Tugulu Group in Xinjiang Province, China, have been attributed as registered by W. homheni individuals. [14] These tracks include the world's smallest stegosaur tracks, measuring 5.7 cm in length, indicative of a dinosaur that was approximately cat-sized. [15]

See also

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>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>Tuojiangosaurus</i> Extinct genus of dinosaurs

Tuojiangosaurus 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.

<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, predominantly in what is now North America, Europe, Africa, South America and Asia. 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.

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>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>

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

Mongolostegus is a genus of stegosaur from the Early Cretaceous (Aptian-Albian) Dzunbain Formation of Mongolia. The type and only species is M. exspectabilis, known from a single specimen previously under the nomen nudumWuerhosaurus mongoliensis.

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

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<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.

<i>Yanbeilong</i> Genus of stegosaurian dinosaurs

Yanbeilong is an extinct genus of stegosaurian dinosaur from the Early Cretaceous (Albian) Zuoyun Formation of Shanxi, China. The type and only species is Y. ultimus. It is considered one of the youngest definitive records of the group, alongside Mongolostegus from Mongolia and possible Stegosaurus remains from the Hekou Group of China, both of which date to the Aptian–Albian.

References

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  5. Galton, P.M.; Carpenter, K. (2016). "The plated dinosaur Stegosaurus longispinus Gilmore, 1914 (Dinosauria: Ornithischia; Upper Jurassic, western USA), type species of Alcovasaurus n. gen."". Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen. 279 (2): 185–208. doi:10.1127/njgpa/2016/0551.
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  12. 1 2 Carpenter, K. (2010). "Species concept in North American stegosaurs". Swiss Journal of Geosciences . 103 (2): 155–162. Bibcode:2010SwJG..103..155C. doi: 10.1007/s00015-010-0020-6 . S2CID   85068121.
  13. Donovan, T. (2002). "RE: Tsagantsabian age". Dinosaur Mailing List. Cleveland Museum of Natural History. Retrieved 2018-01-08.
  14. Xing, Lida; Lockley, Martin G.; Persons, W. Scott; Klein, Hendrik; Romilio, Anthony; Wang, Donghao; Wang, Miaoyan (2021-02-28). "Stegosaur Track Assemblage from Xinjiang, China, Featuring the Smallest Known Stegosaur Record". PALAIOS. 36 (2): 68–76. Bibcode:2021Palai..36...68X. doi:10.2110/palo.2020.036. ISSN   0883-1351. S2CID   233129489.
  15. Queensl, The University of; Lucia, Australia Brisbane St; Gatton, QLD 4072 +61 7 3365 1111 Other Campuses: UQ; Maps, UQ Herston; Queensl, Directions © 2021 The University of. "Tiny cat-sized stegosaur leaves its mark". UQ News. Retrieved 2021-04-19.{{cite web}}: CS1 maint: numeric names: authors list (link)