Hoplitosaurus

*Hoplitosaurus marshi*

***Hoplitosaurus*** (meaning "Hoplite lizard") was a genus of armored dinosaur related to *Polacanthus*. It was named from a partial skeleton found in the ?Barremian-age Lower Cretaceous Lakota Formation of Custer County, South Dakota. It is an obscure genus which has been subject to some misinterpretation of its damaged remains. Although there was a push to synonymize it with *Polacanthus* in the late 1980s-early 1990s, *Hoplitosaurus* has been accepted as a valid albeit poorly known genus in more recent reviews.

## History and Taxonomy

The holotype specimen, USNM 4752, was discovered in 1898 by Nelson Horatio Darton, near Buffalo Gap Station, and consisted of ribs, caudal vertebrae, part of a right scapulocoracoid, parts of both humeri, a right femur, and a variety of armor (including tall spines). Frederic Augustus Lucas described it briefly in 1901 as a new species of *Stegosaurus*, but soon gave the material its own genus. Charles W. Gilmore fully described the material in 1914.

William T. Blows and Javier Pereda-Suberbiola both considered the genus to be the same as *Polacanthus*, creating the new combination *Polacanthus marshii*, but this has since been rejected. Ken Carpenter and James Kirkland noted that many of the resemblances between the two were more widely distributed among ankylosaurs than previously thought, or were based on damage to the bones, such as some femoral characters.

However, its similarity to *Polacanthus* has been noted since Lucas renamed it in 1902, the two being most similar in armor, although *Hoplitosaurus* lacks the sacral shield of armor found in *Polacanthus*. Today, both are considered to be polacanthine or polacanthid ankylosaurs, depending on classification preference (see for example [1]), or ankylosaurians of uncertain relationships.

## Paleobiology

Gilmore described the animal as being about 1.2 m (4 ft) tall at the hips. It would have been a quadrupedal herbivore, eating low to the ground; armor was its main defense.

Blows (2001) reconsidered the armor in light of new data on polacanthine dinosaurs, and found it to fall into the following categories:

* Pectoral spines
* Presacral spines
* Splates (spine+plate) from the sacral region
* Tall, asymmetric, hollow-based caudal plates
* Small to large solid-based, ridged ossicles (filling spaces)

## Appearance in other media

### *Jurassic Park*

*Hoplitosaurus* appears on the Holoscape in the Innovation Center, however it is not known if it lives in Jurassic World.

## References

1. ↑ Lucas, F.A. (1901). A new dinosaur, *Stegosaurus marshi*, from the Lower Cretaceous of South Dakota. *Proceedings of the United States National Museum* 23(1224):591-592.
2. ↑ 2.0 2.1 2.2 Gilmore, C.W. (1914). Osteology of the armored Dinosauria in the United States National Museum, with special reference to the genus *Stegosaurus*. *United States National Museum Bulletin* 89:1-136.
3. ↑ 3.0 3.1 Lucas, F.A. (1902). Paleontological notes. The generic name *Omosaurus*. A new generic name for *Stegosaurus marshi*. *Science*, new series 16(402):435.
4. ↑ Blows, W.T. (1987). The armoured dinosaur *Polacanthus foxi* from the Lower Cretaceous of the Isle of Wight. *Palaeontology* 30(3):557-580.
5. ↑ Pereda-Suberbiola, J. (1991). Nouvelle évidence d'une connexion terrestre entre Europe et Amérique du Nord au Crétacé inférior: *Hoplitosaurus* synonyme de *Polacanthus* (Ornithischia: Ankylosauria). *C.R. Academie Science, Paris* 313:971-976. [French]
6. ↑ Pereda-Suberbiola, J. (1994). *Polacanthus* (Ornithischia, Ankylosauria), a transatlantic armoured dinosaur from the Early Cretaceous of Europe and North America. *Palaeontographica Abteilung* A 232(4-6):133-159.
7. ↑ 7.0 7.1 7.2 Carpenter, K., and Kirkland, J.I. (1998). Review of Lower and middle Cretaceous ankylosaurs from North America. In: Lucas, S.G., Kirkland, J.I., and Estep, J.W. (eds.). *Lower and Middle Cretaceous Terrestrial Ecosystems*. *New Mexico Museum of Natural History and Science Bulletin* 14:249-270.
8. ↑ Carpenter, K. (2001). Phylogenetic analysis of the Ankylosauria. In: Carpenter, K. (ed.). *The Armored Dinosaurs*. Indiana University Press:Bloomington, 455-483. Template:ISBN
9. ↑ 9.0 9.1 Vickaryous, M.K., Maryańska, T., and Weishampel, D.B. (2004). Ankylosauria. In: Weishampel, D.B., Dodson, P., and Osmólska, H. (eds.). *The Dinosauria* (second edition). University of California Press:Berkeley, 363-392. Template:ISBN
10. ↑ Blows, W.T. (2001). Dermal armor of the polacanthine dinosaurs. In: Carpenter, K. (ed.). *The Armored Dinosaurs*. Indiana University Press:Bloomington, 363-385. Template:ISBN