Timeline of stegosaur research

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Skeletal mount of Stegosaurus. Natural History Museum, London Stegosaurus.jpg
Skeletal mount of Stegosaurus .

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. [1] 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. [2] 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. [1]


From the time of their earliest description, the chief mystery surrounding stegosaurs was the function of their distinctive back plates. Marsh originally interpreted them as being plates of armor that would protect against predators. In 1910, Richard Swann Lull would agree with this hypothesis. Charles Whitney Gilmore disagreed in 1914 and argued that the only protection a stegosaur could gain from its plates was to appear intimidatingly larger to potential predators. Nearly forty years later, Davitashvili argued that the plates were too fragile to be used for defense and instead used to attract mates and signal the stegosaur's rank in a social hierarchy. [3]

In the late 1970s, James O. Farlow and others would propose that the thin, blood vessel-rich plates helped absorb or lose body heat, depending on the animal's own physiological requirements. [4] This hypothesis was put forth in a broader context of scientists considering the possibility that dinosaurs may have maintained body temperatures and activity levels similar to those of modern birds and mammals, [5] in which case the plates may have served primarily to shed heat rather than gain it. In the late 1980s Buffrenil and others revived the idea that stegosaur plates were display structures, an interpretation that would continue to find favor from researchers like Main and colleagues into the 21st century. [4]

19th century

Regnosaurus jaw fragments. Regnosaurus.jpg
Regnosaurus jaw fragments.
Type specimen of Omosaurus armatus. Hul - Dacentrurus armatus.jpg
Type specimen of Omosaurus armatus .




Othniel Charles Marsh's reconstruction of Stegosaurus. Stego-marsh-1896-US geological survey.png
Othniel Charles Marsh's reconstruction of Stegosaurus .








Holotype of Omosaurus (now Dacentrurus) armatus, from Sir Richard Owen's 1875 monograph. Dacentrurus holotype.jpg
Holotype of Omosaurus (now Dacentrurus ) armatus , from Sir Richard Owen's 1875 monograph.
Holotype of Stegosaurus stenops. Stenops.jpg
Holotype of Stegosaurus stenops .








20th century


Artist's restoration of Dacentrurus. Dacentrurus armatus.png
Artist's restoration of Dacentrurus .
Dacentrurus spike and limb bones. Omosaurus armatus.jpg
Dacentrurus spike and limb bones.









Artist's restoration of Kentrosaurus. Kentrosaurus digital clay reconstruction.png
Artist's restoration of Kentrosaurus .




Ankylosaurs (pictured) were first distinguished from stegosaurs in 1927 by Romer. Ankylosaurus magniventris reconstruction.png
Ankylosaurs (pictured) were first distinguished from stegosaurs in 1927 by Romer.



Skull of Paranthodon. Paranthodon.png
Skull of Paranthodon .





Artist's restoration of Chialingosaurus kuani. Chialingosaurus kuani.png
Artist's restoration of Chialingosaurus kuani .




Fossils of Lexovisaurus. Lexovisaurus.jpg
Fossils of Lexovisaurus .





Artist's restoration of Wuerhosaurus. Wuerhosaurus homheni.png
Artist's restoration of Wuerhosaurus .



Artist's restoration of Tuojiangosaurus. Tuojiangosaurus multispinus.png
Artist's restoration of Tuojiangosaurus .





Artist's restoration of Huayangosaurus taibaii. Huayangosaurus taibaii.png
Artist's restoration of Huayangosaurus taibaii .



Skeletal mount of Kentrosaurus. Berlin Naturkundemuseum Dino Eingangshalle.jpg
Skeletal mount of Kentrosaurus.


Skeletal mount of Chungkingosaurus jiangbeiensis. Chungkingosaurus jiangbeiensis.jpg
Skeletal mount of Chungkingosaurus jiangbeiensis .



Stegosaurus back plate. Stegosaurus dorsal plate - Museum of the Rockies - 2013-07-08.jpg
Stegosaurus back plate.



Tracks supposedly left by stegosaurs in South America may actually have been left by hadrosaurs. Maiasaur Pano-v1.jpg
Tracks supposedly left by stegosaurs in South America may actually have been left by hadrosaurs.





Wuerhosaurus back plate Wuerhosaurus plate at the Paleozoological Museum of China.jpg
Wuerhosaurus back plate






Dravidosaurus may have actually been a plesiosaur. Paleo Hall at HMNS plesiosaur.jpg
Dravidosaurus may have actually been a plesiosaur.




Stegosaurus tail spikes. Thagomizer 01.jpg
Stegosaurus tail spikes.


21st century


Main and others argued that Stegosaurus did not use its plates to regulate its body temperature. Stegosaurus ungulatus.jpg
Main and others argued that Stegosaurus did not use its plates to regulate its body temperature.


Skeletal mount of Hesperosaurus mjosi. Hesperosaurus mjosi skeleton.JPG
Skeletal mount of Hesperosaurus mjosi .






Artist's restoration of Miragaia longicollum. Miragaia.jpg
Artist's restoration of Miragaia longicollum .









See also


  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 Galton and Upchurch (2004); "Introduction", page 343.
  2. Galton and Upchurch (2004); "Table 16.1: Stegosauria", pages 344-345.
  3. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Galton and Upchurch (2004); "Paleoecology and Behavior", page 361.
  4. 1 2 3 4 5 6 7 8 9 Galton and Upchurch (2004); "Paleoecology and Behavior", page 362.
  5. Chinsamy and Hillenius (2004); "Introduction", page 643.
  6. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Galton and Upchurch (2004); "Table 16.1: Stegosauria", page 345.
  7. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Galton and Upchurch (2004); "Table 16.1: Stegosauria", page 344.
  8. Benton (1990); "Racial Senility", page 379.
  9. For Woodward's speech, see Benton (1990); "Racial Senility", page 379. For a definition and discussion of racial senility, see "Post-Darwinian Interpretations", page 376.
  10. 1 2 3 4 Galton and Upchurch (2004); "Taphonomy", page 360.
  11. 1 2 3 4 Galton and Upchurch (2004); "Paleoecology and Behavior", page 360.
  12. Galton and Upchurch (2004); "Introduction", page 343. For the original publication, see Jenny and Jossen (1982)
  13. 1 2 Galton and Upchurch (2004); "Systematic and Evolution", page 358.
  14. Galton and Upchurch (2004); "Taphonomy", page 360. For the original publication, see Heinrich (1999).
  15. Chengkai et al. (2007); "Abstract", page 351.
  16. Maidment et al. (2008); "Synopsis", page 367.
  17. Mateus, Maidment and Christiansen (2009); "Abstract", page 1815.
  18. Cameron, Cameron, and Barnett (2015); in passim.
  19. Galton and Carpenter (2016); in passim.
  20. Cameron, Cameron, and Barnett (2016); in passim.
  21. T. A. Tumanova; V. R. Alifanov (2018). "First record of stegosaur (Ornithischia, Dinosauria) from the Aptian–Albian of Mongolia". Paleontological Journal. 52 (14): 1771–1779. doi:10.1134/S0031030118140186. S2CID   91559457.
  22. Marco Romano (2019). "Disparity vs. diversity in Stegosauria (Dinosauria, Ornithischia): cranial and post-cranial sub-dataset provide different signals". Historical Biology: An International Journal of Paleobiology. 31 (7): 857–865. doi:10.1080/08912963.2017.1397655. S2CID   89787668.
  23. Bao-Qiao Hao; Yong Ye; Susannah C R. Maidment; Sergio Bertazzo; Guang-Zhao Peng; Hai-Lu You (2019). "Femoral osteopathy in Gigantspinosaurus sichuanensis (Dinosauria: Stegosauria) from the Late Jurassic of Sichuan Basin, Southwestern China". Historical Biology: An International Journal of Paleobiology. 32 (8): 1–8. doi:10.1080/08912963.2018.1561673. S2CID   91554634.
  24. Maidment, Susannah C. R.; Raven, Thomas J.; Ouarhache, Driss; Barrett, Paul M. (2019-08-16). "North Africa's first stegosaur: Implications for Gondwanan thyreophoran dinosaur diversity". Gondwana Research. 77: 82–97. doi: 10.1016/j.gr.2019.07.007 . hdl: 10141/622706 . ISSN   1342-937X.
  25. Dai, H.; Li, N.; Maidment, S. C. R.; Wei, G.; Zhou, Y. X.; Hu, X. F.; Ma, Q. Y.; Wang, X. Q.; Hu, H. Q.; Peng, G. Z. (2022). "New Stegosaurs from the Middle Jurassic Lower Member of the Shaximiao Formation of Chongqing, China". Journal of Vertebrate Paleontology. 41 (5): e1995737. doi: 10.1080/02724634.2021.1995737 . S2CID   247267743.

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<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.

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

Thyreophora is a group of armored ornithischian dinosaurs that lived from the Early Jurassic until the end of the Cretaceous.

<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.

<span class="mw-page-title-main">Thagomizer</span> Spiked structure on the tails of dinosaurs of the family Stegosauria

A thagomizer is the distinctive arrangement of four spikes on the tails of stegosaurian dinosaurs. These spikes are believed to have been a defensive measure against predators.

<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 to Early Cretaceous of Europe. Its type species, Omosaurus armatus, was named in 1875, based on a skeleton found in a clay pit in the Kimmeridge Clay in Swindon, 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. Finds of this animal have been limited and much of its appearance is uncertain. It was a heavily built quadrupedal herbivore, adorned with plates and spikes, reaching 8–9 metres (26–30 ft) in length and 5 metric tons in body mass.

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

Dravidosaurus is a controversial taxon of Late Cretaceous reptiles, variously interpreted as either a ornithischian, possibly stegosaurian, dinosaur or a plesiosaur. The genus contains a single species, D. blanfordi, known from mostly poorly preserved fossils from the Coniacian of southern India.

<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>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

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

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<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, Huayangosaurus taibaii, lived in China.

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

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

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<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>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, and in 2019 recombined as Miragaia longispinus.

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

This timeline of ankylosaur research is a chronological listing of events in the history of paleontology focused on the ankylosaurs, quadrupedal herbivorous dinosaurs who were protected by a covering bony plates and spikes and sometimes by a clubbed tail. Although formally trained scientists did not begin documenting ankylosaur fossils until the early 19th century, Native Americans had a long history of contact with these remains, which were generally interpreted through a mythological lens. The Delaware people have stories about smoking the bones of ancient monsters in a magic ritual to have wishes granted and ankylosaur fossils are among the local fossils that may have been used like this. The Native Americans of the modern southwestern United States tell stories about an armored monster named Yeitso that may have been influenced by local ankylosaur fossils. Likewise, ankylosaur remains are among the dinosaur bones found along the Red Deer River of Alberta, Canada where the Piegan people believe that the Grandfather of the Buffalo once lived.