Open Paleo

Hypsirhophus

Cope, 1878 HIP-si-ROH-fus Disputed

From Greek hypsi (high) and rhophos (roof); meaning "high roof", referring to the tall dorsal vertebrae. Cope's original spelling "Hypsirophus" (without the second h) is considered a typesetting variant.

161.5–137.1 million years ago Oxfordian–Berriasian, Late Jurassic–Early Cretaceous
Late Jurassic and Early Cretaceous stages

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 a partial dorsal vertebra, a rib fragment, two neural arches from the front of the tail, and two centra from farther down the tail.

Under dispute

The validity of Hypsirhophus is contested. Maidment and colleagues (2008) treated Hypsirhophus discursus as a junior synonym of Stegosaurus armatus, while other workers retain it as a poorly known but possibly distinct stegosaur (Carpenter and colleagues, 2001; Galton, 2010). It is retained at Stegosauria incertae sedis.

Diagnosis

  1. Dorsal zygapophyses extraordinarily elevated, standing on a stem composed of the neurapophyses
  2. Anterior zygapophyses of dorsal vertebrae united on the midline, forming a basin receiving the posterior zygapophyses
  3. Neural arch and spine of dorsal vertebra m. 0.575 high; spine m. 0.040 wide at base and m. 0.130 wide at summit
  4. Caudal centrum m. 0.175 wide and m. 0.160 high; neural arch expanded transversely at summit
  5. Dorsal vertebra centrum m. 0.105 wide; centrum to base of neural arch m. 0.105, to posterior zygapophyses m. 0.300

Species

Hypsirhophus discurus Cope, 1878 Disputed

Type species

No meaning was assigned by Cope (1878).

Holotype
AMNH 5731 , American Museum of Natural History
Material
Dorsal vertebra with elevated zygapophyses on a stem of neurapophyses, two partial neural spines, two caudal centra, and a rib fragment.
Horizon
Morrison Formation, Oxfordian–Berriasian, Late Jurassic–Early Cretaceous , 161.5–137.1 million years ago The age of the containing rock unit; no finer age has been published.
Locality
Cope's Quarry 3, Colorado, United States Galton (2010) supplies the quarry designation; Cope (1878) names no quarry.

Synonyms of the genus

Name Type Reason
Hypsirhophus seeleyanus nomen nudum Second species erected by Cope (1879) on dorsal and caudal vertebrae, teeth, and a femur from an unknown locality in Colorado named in honor of Professor Seeley; the original description is generally regarded as inadequate, making the name a nomen nudum.
Hypsirophus emended spelling Cope's original spelling, later emended to Hypsirhophus, which is the form in modern use. Olshevsky (1991) takes the opposite view, treating Hypsirophus as the correct rendering and the second-h form as an error.

References

  1. Cope, E. D. (1878). A new genus of Dinosauria from Colorado. American Naturalist 12(3): 188-189.

    Brief General Notes entry erecting Hypsirhophus discurus on vertebral material from the "Dakota Beds" of Colorado (now Morrison Formation); Cope proposed no formal higher placement beyond Dinosauria.

    cope1878a
  2. Cope, E. D. (1879). New Jurassic Dinosauria. American Naturalist 13: 402-404.

    Treats Hypsirhophus as a carnivorous dinosaur on associated vertebrae, limb bones and teeth, and erects H. seeleyanus (later a nomen nudum); also names Camarasaurus leptodirus.

    cope1879a
  3. Carpenter, K.; Miles, C. A.; Cloward, K. (2001). New primitive stegosaur from the Morrison Formation, Wyoming. The Armored Dinosaurs 55-75. Indiana University Press, Bloomington.

    Treats Hypsirhophus discurus as valid, stating it "differs enough from Stegosaurus to warrant recognition"; restricts it to Morrison Dinosaur Zone 4.

    carpenter2001b
  4. Maidment, S. C. R.; Norman, D. B.; Barrett, P. M.; Upchurch, P. (2008). Systematics and phylogeny of Stegosauria (Dinosauria: Ornithischia). Journal of Systematic Palaeontology 6(4): 367-407. Informa UK Limited. doi:10.1017/S1477201908002459

    Treated Hypsirhophus discursus as a junior synonym of Stegosaurus armatus.

    maidment2008a
  5. Galton, P. M. (2010). Species of plated dinosaur Stegosaurus (Morrison Formation, Late Jurassic) of western USA: new type species designation needed. Swiss Journal of Geosciences 103(2): 187-198. Springer Science and Business Media LLC. doi:10.1007/s00015-010-0022-4

    Bearing on the validity of Hypsirhophus relative to Stegosaurus.

    galton2010a
  6. Olshevsky, G. (1991). A revision of the parainfraclass Archosauria Cope, 1869, excluding the advanced Crocodylia. Mesozoic Meanderings 2: 1-196.

    Records the competing spellings of the name and treats Hypsirophus as the correct rendering.

    olshevsky1991a