Streptospondylus

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Streptospondylus
Temporal range:
Ma
↓
Tibia, astragalus and calcaneum of Streptospondylus altdorfensis
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: †
Megalosauria
Genus: †Streptospondylus
von Meyer, 1832
Species:
†S. altdorfensis
Binomial name
†Streptospondylus altdorfensis
von Meyer, 1832
Synonyms[1]

Streptospondylus (meaning "reversed vertebra") is a

theropod dinosaur known from the Late Jurassic period of France, 161 million years ago. It was a medium-sized predator with an estimated length of 6 meters (19.5 ft) and a weight of 500 kg (1,100 lbs).[2]

Discovery and naming

Restoration in its habitat

Streptospondylus was one of the first dinosaurs collected and was the first described, though not the first dinosaur named. It was not recognised as a theropod dinosaur until 2001.[1]

In 1778, abbey Charles Bacheley, a Norman naturalist, reported the presence of fossil bones in the Callovo-Oxfordian formations, either the

Muséum National d'Histoire Naturelle in Paris. In 1800, these fossils were briefly mentioned by Georges Cuvier who misspelled the name of their former owner as Bachelet.[5]

In 1808, Cuvier scientifically described the theropod vertebrae as the first dinosaur remains ever. However, he considered them to be crocodilian and associated them with fossils of the Teleosauridae and the Metriorhynchidae.[6] In 1822, Cuvier by the work of Henry De La Bèche became aware that these finds were very disparate, stemming from different periods. He abstained from naming them but in 1824 concluded that there were two main types. In 1825 Étienne Geoffroy Saint-Hilaire accordingly named two crocodilian skulls as the genus Steneosaurus, the one, specimen MNHN 8900, becoming Steneosaurus rostromajor, the other, MNHN 8902, S. rostrominor.[7]

In 1832 however, the German

binomial name
(also) referring to a theropod.

Type specimen of S. cuvieri

In 1842

Laelaps gallicus and Friedrich von Huene in 1909 a Megalosaurus
cuvieri.

In 1964,

type specimen, MNHN 1920–7.[10] In 1977 Philippe Taquet created the genus Piveteausaurus
for this species.

In 2001,

junior synonyms.[1]

The lectotype specimens, MNHN 8605-09, 8787-89, 8793-94, 8907, were probably found at the coast in layers of the Falaises des Vaches Noires near Calvados, dating from the late Callovian or early Oxfordian, about 161 million years old. They consist of several vertebrae series, single vertebrae, a partial left pubis and limb elements. The longest vertebra has a length of 97 millimetres, indicating a total body length of about seven metres. Also a partial left femur, MNHN 9645, has been referred. Streptospondylus has been diagnosed by the unique bifurcation (split) of the hypapophyses (processes which extend from the lower surface of a vertebra) in the anterior dorsal vertebrae.[11]

Material referred to S. major by Owen

Owen also named two other species, S. major

iguanodont material. His S. cuvieri, of which the type specimen is lost, is today considered a nomen dubium
.

In 2010 Gregory S. Paul renamed (as an informal name) Magnosaurus into Streptospondylus nethercombensis.[2]

In 2022, theropod specimens from the same locality as the type of Streptospondylus, long held in private collections, were described. It was found that some dorsal vertebrae (MNHN.F.RJN472;B5) bore autapomorphies of Streptospondylus, while a cervical vertebra (MPV 2020.1.11), a tibia (MPV 2020.1.2) and a femur were referred to the species, based on shared characters with the related genus Eustreptospondylus.[14]

Phylogeny

Earlier assigned to crocodilian groups, Streptospondylus was in the 20th century typically classified in the Megalosauridae.

Recent analyses indicate that Streptospondylus is a

cladistic analysis by Benson and colleagues from 2010 indicated that Streptospondylus was the sister species of Magnosaurus within the Megalosauridae.[16]
Carrano et al. (2012) placed Streptospondylus at
Megalosauria incertae sedis due to its fragmentary nature.[17]

Megalosauroidea

References

  1. ^ a b c Allain R (2001). "Redescription de Streptospondylus altdorfensis, le dinosaure théropode de Cuvier, du Jurassique de Normandie [Redescription of Streptospondylus altdorfensis, Cuvier's theropod dinosaur from the Jurassic of Normandy]". Geodiversitas. 23 (3): 349–367.
  2. ^ a b Paul, G.S. 2010. The Princeton Field Guide to Dinosaurs. Princeton University Press, 89 pp
  3. ^ a b Brignon, A. (2016) Abbé Bacheley and the discovery of the first dinosaurs and marine crocodilians from the Jurassic of the Vaches Noires (Callovian/Oxfordian, Normandy, France). Comptes Rendus Palevol 15 : 595–605 (in French with an abridged English version).
  4. ^ Brignon, A. (2016) Le premier "chasseur de dinosaures" en France : l'abbé Charles Bacheley (1716-1795). Fossiles: Revue française de Paléontologie 27 : 36-42.
  5. ^ Cuvier G (1800). "Sur une nouvelle espèce de crocodile fossile". Bulletin des Sciences, Société Philomathique de Paris. 2: 159.
  6. ^ Cuvier G (1808). "Sur les ossements fossiles de crocodiles et particulièrement sur ceux des environs du Havre et d'Honfleur, avec des remarques sur les squelettes de sauriens de la Thuringe". Annales du Muséum d'Histoire naturelle de Paris. XII: 73–110.
  7. ^ Geoffroy Saint-Hilaire E (1825). "Recherches sur l'organisation des gavials". Mémoires du Muséum national d'Histoire naturelle. 12: 97–155.
  8. ^ Meyer, H. von, (1832), Paleologica zur Geschichte der Erde, Frankfurt am Main, 560 p
  9. ^ a b Owen R (1842). "Report on British fossil reptiles". Report of the British Association for the Advancement of Science. 11: 60–204.
  10. doi:10.1098/rstb.1964.0009
    .
  11. S2CID 85354215
    .
  12. ^ Mantell, G. A., 1851, Petrifactions and their teachings; or a hand-book to the Gallery of Organic remains of The British Museum, London, 496pp.
  13. ^ Owen, R., 1854a. Descriptive catalogue of the fossil organic remains of reptilia and pisces contained in the Museum of The Royal College of Surgeons of England: 184pp.
  14. ^ Monvoison, Evariste; Allain, Ronan; Buffetaut, Eric; Picot, Laurent (2022). "New data on the theropod diversity from the Middle to Late Jurassic of the Vaches Noires cliffs (Normandy, France)" (PDF). Geodiversitas. 44 (12): 385–415.
  15. doi:10.1111/j.1096-3642.2009.00569.x
    .
  16. S2CID 22646156.{{cite journal}}: CS1 maint: multiple names: authors list (link) Supporting Information
  17. ^ M. T. Carrano, R. B. J. Benson, and S. D. Sampson. 2012. The phylogeny of Tetanurae (Dinosauria: Theropoda). Journal of Systematic Palaeontology 10(2):211-300
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