''Hypsirhophus'' (meaning "high roof"; often misspelled "''Hypsirophus''") is 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 ...

stegosauria 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, ...

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 ...

s. It contains a single

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

, ''Hypsirhophus discurus'', which is known only from a fragmentary specimen. The

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

consists of partial vertebrae from the back, three from the

tail The tail is the section at the rear end of certain kinds of animals’ bodies; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, r ...

, and a piece 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 ...

History and classification

The first described fossils of ''Hypsirhophus discurus'' were unearthed by schoolteacher Oramel William Lucas who working for

Edward Drinker Cope Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontologist, comparative anatomist, herpetologist, and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested ...

at Cope's Quarry 3 near "Cope's Nipple" at Garden Park, a fossil site 3.8 miles northeast of Canon City,

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...

, and came from the

Tithonian In the geological timescale, the Tithonian is the latest age of the Late Jurassic Epoch and the uppermost stage of the Upper Jurassic Series. It spans the time between 152.1 ± 4 Ma and 145.0 ± 4 Ma (million years ago). It is preceded by the K ...

strata of the

Upper Jurassic The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987. In European lithostratigraphy, the name ...

. The fossils now accepted as ''Hypsirhophus'' were fragmentary and came from one individual, containing: a dorsal vertebra, 2 partial neural spines, 2 caudal

vertebral centra 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 ...

, and a

fragment. These fossils were then sent to Cope, who briefly described them in 1878 as part of the

Bone Wars The Bone Wars, also known as the Great Dinosaur Rush, was a period of intense and ruthlessly competitive fossil hunting and discovery during the Gilded Age of American history, marked by a heated rivalry between Edward Drinker Cope (of the Acade ...

, a competition between Cope and the

Yale Yale University is a private research university in New Haven, Connecticut. Established in 1701 as the Collegiate School, it is the third-oldest institution of higher education in the United States and among the most prestigious in the wor ...

paleontologist

Othniel Charles Marsh Othniel Charles Marsh (October 29, 1831 – March 18, 1899) was an American professor of Paleontology in Yale College and President of the National Academy of Sciences. He was one of the preeminent scientists in the field of paleontology. Among h ...

over fossils from the

American West The Western United States (also called the American West, the Far West, and the West) is the region comprising the westernmost states of the United States. As American settlement in the U.S. expanded westward, the meaning of the term ''the Wes ...

.Cope, E. D. (1879). New Jurassic Dinosauria. ''American Naturalist'', ''13'', 402-404. Cope incorrectly grouped a theropod femur, possibly from '' Allosaurus'', found nearby into the specimen causing him to believe it was a theropod related to ''

Laelaps The name Laelaps is a name attributed to the following: * Laelaps (mythology) Laelaps ( grc-gre, Λαῖλαψ, ''gen''.: means "hurricane") (Lelaps, Lalaps, Lailaps) was a Greek mythological dog that never failed to catch what it was hunting. ...

'' or '' Megalosaurus'' and possibly even synonymous with a species of the former that he described, ''Laelaps trihedrodon''.Cope, E. D. (1878). A new genus of Dinosauria from Colorado. ''American Naturalist'', ''12'', 181. The generic name of ''Hypsirhophus'' means "high roof" after the tall anatomy of the dorsal vertebrae, while the specific name hasn't been translated. The next year in 1879, Cope named another species, ''Hypsirhophus'' "seeleyanus", based on several vertebrae, limb bones, and teeth from an unknown locality in Colorado that have since been lost, but were theropod fossils instead of stegosaurian. Cope also inadequately named the species, making it a nomen nudum. The holotype of ''Hypsirhophus discurus'' was transferred to the American Museum of Natural History after Cope's death in 1897, where it's under specimen number AMNH 5731. It wasn't until many years later and the descriptions of complete ''Stegosaurus'' skeletons that ''Hypsirhophus'' was classified as a stegosaur, with Cope's rival Marsh placing ''Hypsirhophus'' in

Stegosauridae Stegosauridae is a family of thyreophoran dinosaurs (armoured dinosaurs) within the suborder Stegosauria. The clade is defined as all species of dinosaurs more closely related to ''Stegosaurus'' than ''Huayangosaurus''.David B. Weishampel, Peter ...

in 1892.Marsh, O. C. (1896)
''The dinosaurs of North America''.
US Government Printing Office. Some later researchers have considered ''Hypsirhophus'' to be a synonym of '' Stegosaurus'', or a ''

nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a s ...

'', though Kenneth Carpenter and Peter Galton have suggested that it is distinct and valid based on differences in the vertebrae.

Description

Due to the fragmentary nature of the type specimen, lack of description, and the single known specimen, little is known from ''Hypsirhophus.'' Kenneth Carpenter noted that it could be diagnosed by: Circular fossa between

postzygapophyses The articular processes or zygapophyses (Greek ζυγον = "yoke" (because it links two vertebrae) + απο = "away" + φυσις = "process") of a vertebra are projections of the vertebra that serve the purpose of fitting with an adjacent vertebr ...

in ''Hypsirhophus'' versus vertical grooves in ''Stegosaurus,'' Median ridge extending from base of postzygapophyses to neural canal versus no ridge groove in ''Stegosaurus ungulatus'' (as ''S. stenops'') In cross-section of pedicel, the anterior surface is convex versus being concave in ''Stegosaurus.'' The dorsal vertebrae are very tall, at 47 centimeters tall despite being incomplete and some of the largest dorsals known.

References

{{Taxonbar, from=Q15723432 Stegosaurs Dinosaurs of the Morrison Formation Late Jurassic dinosaurs of North America Morrison fauna Fossil taxa described in 1878 Paleontology in Colorado