''Hoplitosaurus'' (meaning "

Hoplite Hoplites ( ) ( grc, ὁπλίτης : hoplítēs) were citizen-soldiers of Ancient Greece, Ancient Greek Polis, city-states who were primarily armed with spears and shields. Hoplite soldiers used the phalanx formation to be effective in war with ...

lizard") was a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of armored

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

related to ''

Polacanthus ''Polacanthus'', deriving its name from the Ancient Greek polys-/πολύς- "many" and akantha/ἄκανθα "thorn" or "prickle", is an early armoured, spiked, plant-eating ankylosaurian dinosaur from the early Cretaceous period of England. I ...

''. It was named from a partial skeleton found in the ?

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is preceded ...

-age

Lower Cretaceous Lower may refer to: *Lower (surname) *Lower Township, New Jersey *Lower Receiver (firearms) *Lower Wick Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is situated about five miles south west of Dursley, eight ...

Lakota Formation The Lakota Formation is a sequence of rocks of early Cretaceous (Berriasian to Barremian) age from Western North America. Located in South Dakota, the name of the formation is derived from the Lakota Native American tribe. There are two units of ...

of Custer County,

South Dakota South Dakota (; Sioux language, Sioux: , ) is a U.S. state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Lakota people, Lakota and Dakota peo ...

. 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 A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

specimen, USNM 4752, was discovered in 1898 by

Nelson Horatio Darton Nelson Horatio Darton (December 17, 1865 – February 28, 1948) was a geologist who worked for the United States Geological Survey. He was born in Brooklyn, New York, started working in his uncle's drug business at thirteen years old, and b ...

, near Buffalo Gap Station, and consisted of

rib In vertebrate anatomy, ribs ( la, costae) are the long curved bones which form the rib cage, part of the axial skeleton. In most tetrapods, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the ches ...

s, caudal

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...

e, part of a right

scapulocoracoid The scapulocoracoid is the unit of the pectoral girdle that contains the coracoid and scapula. The coracoid itself is a beak-shaped bone that is commonly found in most vertebrates with a few exceptions. The scapula is commonly known as the ''shoulde ...

, parts of both

humeri The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a round ...

, a right

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with ...

, and a variety of

armor Armour (British English) or armor (American English; see spelling differences) is a covering used to protect an object, individual, or vehicle from physical injury or damage, especially direct contact weapons or projectiles during combat, or fr ...

(including tall spines).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.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. Frederic Augustus Lucas described it briefly in 1901 as a new species of ''

Stegosaurus ''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 foun ...

'', but soon gave the material its own genus.Lucas, F.A. (1902). Paleontological notes. The generic name ''Omosaurus''. A new generic name for ''Stegosaurus marshi''. ''Science'', new series 16(402):435.

Charles W. Gilmore Charles Whitney Gilmore (March 11, 1874 – September 27, 1945) was an American paleontologist who gained renown in the early 20th century for his work on vertebrate fossils during his career at the United States National Museum (now the N ...

fully described the material in 1914. William T. BlowsBlows, W.T. (1987). The armoured dinosaur ''Polacanthus foxi'' from the Lower Cretaceous of the Isle of Wight. ''Palaeontology'' 30(3):557-580. and

Javier Pereda-Suberbiola Javier may refer to: Arts, entertainment, and media * Javier, in video game '' Advance Wars: Dual Strike'' * Javier Rios, a character in the Monsters, Inc. franchise. * ''Javier'' (album), a 2003 album by the American singer Javier Colon, known ...

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.

rench The Rench is a right-hand tributary of the Rhine in the Ortenau (Baden (Land), Central Baden, Germany). It rises on the southern edge of the Northern Black Forest at Kniebis near Bad Griesbach im Schwarzwald. The source farthest from the mouth is ...

/ref>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. both considered the genus to be the same as ''

'', creating the new combination ''Polacanthus marshii'', but this has since been rejected.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. 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 Sacral may refer to: *Sacred Sacred describes something that is dedicated or set apart for the service or worship of a deity; is considered worthy of spiritual respect or devotion; or inspires awe or reverence among believers. The property ...

shield of armor found in ''Polacanthus''. Today, both are considered to be polacanthine or polacanthid ankylosaurs,Carpenter, K. (2001). Phylogenetic analysis of the Ankylosauria. In: Carpenter, K. (ed.). ''The Armored Dinosaurs''. Indiana University Press:Bloomington, 455-483. depending on classification preference (see for exampl

, or ankylosaurians of uncertain relationships.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.

Paleobiology

Gilmore described the animal as being about 1.2 m (4 ft) tall at the hips. It would have been a

quadruped Quadrupedalism is a form of locomotion where four limbs are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four limbs is said to be a quadruped (from Latin ''quattuor' ...

herbivore A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

, 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:Blows, W.T. (2001). Dermal armor of the polacanthine dinosaurs. In: Carpenter, K. (ed.). ''The Armored Dinosaurs''. Indiana University Press:Bloomington, 363-385. *

Pectoral Pectoral may refer to: * The chest region and anything relating to it. * Pectoral cross, a cross worn on the chest * a decorative, usually jeweled version of a gorget * Pectoral (Ancient Egypt), a type of jewelry worn in ancient Egypt * Pectorali ...

spines *

Presacral In human anatomy, the presacral space is inside the pelvis, behind the rectum and in front of the coccyx and sacrum. Normally it is empty, or it contains a pocket of fat. It is usually covered by sigmoid colon. Clinical significance The presacral ...

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

References

External links

Polacanthidae
at

Tree of Life The tree of life is a fundamental archetype in many of the world's mythological, religious, and philosophical traditions. It is closely related to the concept of the sacred tree.Giovino, Mariana (2007). ''The Assyrian Sacred Tree: A History ...

{{Taxonbar, from=Q139951 Nodosaurids Early Cretaceous dinosaurs of North America Fossil taxa described in 1902 Paleontology in South Dakota Ornithischian genera

History and Taxonomy

Paleobiology

See also

References

External links