Ornithodesmus

Source: Wikipedia, the free encyclopedia.

Ornithodesmus
Temporal range:
Ma
↓
Illustration of the holotype sacrum in multiple views
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Family: †Dromaeosauridae
Genus: †Ornithodesmus
Seeley, 1887
Species:
†O. cluniculus
Binomial name
†Ornithodesmus cluniculus
Seeley, 1887

Ornithodesmus (meaning "bird link") is a

theropod, specifically a dromaeosaur, making it one of the first dromaeosaurs known to science. All pterosaurian material previously assigned to this genus has been renamed Istiodactylus
.

Description

As it is only known from isolated vertebrae, little is known about the appearance of Ornithodesmus. The neural spines of the vertebrae are fused and form a blade over the 9.6 centimetres long sacrum, which is slightly arched. The bases of the neural spines form a lateral platform, and the first two vertebrae of the sequence have deep hollow cavities, which formed space for air sacs.[2]

Based on its apparent identity as a dromaeosaur, it was probably carnivorous, and likely measured about 1.8 meters (5.9 feet) long in life. Dromaeosaur teeth probably belonging to a velociraptorine are known from the same formation, but are too large to have belonged to Ornithodesmus; rather, these must have come from a theropod closer in size to the giant Utahraptor.[3]

History and classification

Modern photo of the holotype sacrum, with museum labels and a note written on 20 May 1988 confirming that Ornithodesmus cluniculus was not a pterosaur

Ornithodesmus cluniculus was first described by

BMNH R187, found by William Fox in the Wessex Formation of Brook Bay. Seeley thought the bones came from a primitive bird, and gave it a name meaning "bird link",[1] from Greek ὄρνις (ornis), "bird", en δεσμός (desmos), "link". The specific name cluniculus means "little buttock" in Latin
, a reference to the small thighs indicated by the size of the specimen.

Later that year,

Reginald Walter Hooley named a new family to distinguish Ornithodesmus from other large pterosaurs known at the time, Ornithodesmidae.[6]

In 1993, Stafford C. Howse and Andrew Milner re-examined the type specimen of O. cluniculus and determined that Seeley had incorrectly referred the pterosaur species to this genus. They identified O. cluniculus as a theropod dinosaur. Specifically, they suggested it was a troodontid, based on its similarity to the supposed troodontid specimen BMNH R4463.[7] However, later study by Peter Makovicky and Mark Norell showed this specimen to be a dromaeosaurid; because of this mis-identification, they suggested Ornithodesmus was likely a dromaeosaurid as well.[8] Darren Naish and colleagues in 2001 argued against a dromaeosaurid identity for Ornithodesmus, suggesting instead it was related to the ceratosaurs or coelophysids.[2] However, those scientists later changed their opinions, publishing a paper in 2007 that agreed with previous studies and classifying Ornithodesmus as a dromaeosaurid.[3] A 2019 analysis placed Ornithodesmus in family Unenlagiidae, otherwise considered a subgroup of Dromaeosauridae.[9]

The more complete pterosaur specimens that had long been associated with the name Ornithodesmus were given a new name in 2001, Istiodactylus.[10]

See also

References

  1. ^ a b Seeley, H. (1887). "On a sacrum, apparently indicating a new type of Bird, Ornithodesmus cluniculus, Seeley, from the Wealden of Brook." Quarterly Journal of the Geological Society of London, 42: 206-211.
  2. ^ a b Naish, D. Hutt, and Martill, D.M. (2001). "Saurischian dinosaurs: theropods." in Martill, D.M. and Naish, D. (eds). Dinosaurs of the Isle of Wight. The Palaeontological Association, Field Guides to Fossils. 10, 242-309.
  3. ^ a b Naish, D. and Martill, D. M. (2007). "Dinosaurs of Great Britain and the role of the Geological Society of London in their discovery: basal Dinosauria and Saurischia." Journal of the Geological Society, London, 164(3): 493-510
  4. ^ Anonymous (1887). "Discussion (on Ornithodesmus and Patricosaurus)." Quarterly Journal of the Geological Society of London, 43: 219-220.
  5. ^ Seeley, H. (1901). Dragons of the Air. London: Methuen & Co. 239 pp.
  6. ^ Hooley, R.W. (1913). "The skeleton of Ornithodesmus latidens; an Ornithosaur from the Wealden Shales of Atherfield (Isle of Wight)." Quarterly Journal of the Geological Society, 69(1-4): 372-422.
  7. ^ Howse, S.C.B. and Milner, A.R. (1993). "Ornithodesmus—a maniraptoran theropod dinosaur from the Lower Cretaceous of the Isle of Wight, England." Palaeontology, 36: 425–437.
  8. ^ Norell, M.A. and Makovicky, P. (1997). "Important features of the dromaeosaur skeleton: Information from a new specimen." American Museum Novitates, 3215: 1-28.
  9. PMID 31333906
    .
  10. ^ Howse, Milner and Martill (2001). "Pterosaurs." in Martill, D.M. and Naish, D. (eds.). Dinosaurs of the Isle of Wight. The Palaeontological Association, London. pp. 324-335.

External links

Retrieved from "https://en.wikipedia.org/w/index.php?title=Ornithodesmus&oldid=1196844488"