Open Paleo

Ornithodesmus

Seeley, 1887 Nomen dubium

From Greek 'ornis' (bird) and 'desmos' (link or bond); meaning 'bird link'.

125.8–121.4 million years ago Barremian, Early Cretaceous
Early Cretaceous stages

Ornithodesmus is a genus of small, dromaeosaurid dinosaur from the Isle of Wight in England, dating to about 125 million years ago. The name, along with that of the type and only species, O. cluniculus, was originally assigned to a bird-like sacrum (a series of vertebrae fused to the hip bones), initially believed to come from a bird and subsequently identified as a pterosaur. More complete pterosaur remains were later assigned to Ornithodesmus. More recently, a detailed analysis determined that the original specimen in fact came from a small 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.

Under dispute

Ornithodesmus cluniculus is based on a single sacrum long misidentified as a bird (Seeley, 1887) and then a pterosaur before Howse and Milner (1993) reidentified it as a small theropod and regarded the genus as a nomen vanum given the limited material. It was later referred to Dromaeosauridae (Naish and Martill, 2007) and recovered as a very basal dromaeosaurid, possibly a member of Unenlagiidae (Hartman and colleagues, 2019). Given the fragmentary type its validity and precise placement remain debated; it is retained at Dromaeosauridae incertae sedis.

Species

Ornithodesmus cluniculus Seeley, 1887 Nomen dubium

Type species

Holotype
BMNH R187 , Natural History Museum
Material
Poorly preserved sacrum comprising six ankylosed vertebrae, about 96 mm long
Horizon
Wessex Formation, Barremian, Early Cretaceous , 125.8–121.4 million years ago
Locality
Brook, Isle of Wight, United Kingdom

References

  1. Seeley, H. G. (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 43(1-4): 206-211. Geological Society of London. doi:10.1144/gsl.jgs.1887.043.01-04.19 seeley1887b
  2. Howse, S. C. B.; Milner, A. R. (1993). Ornithodesmus—a maniraptoran theropod dinosaur from the Lower Cretaceous of the Isle of Wight, England. Palaeontology 36: 425-437.

    Redescription of the holotype sacrum; removed it from Pterosauria and referred it to Theropoda (as a troodontid), treating the genus as a nomen vanum given the limited material.

    howse1993a
  3. Naish, D.; 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 164(3): 493-510. doi:10.1144/0016-76492006-032

    Bicentennial review of British saurischians; identifies Ornithodesmus as a probable dromaeosaurid based on the sacrum from the Wessex Formation.

    naish2007a
  4. Hartman, S.; Mortimer, M.; Wahl, W. R.; Lomax, D. R.; Lippincott, J.; Lovelace, D. M. (2019). A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ 7: e7247. PeerJ. doi:10.7717/peerj.7247

    Paravian phylogeny recovering Ornithodesmus as a very basal dromaeosaurid/unenlagiid.

    hartman2019a