Calamospondylus Explained

Calamospondylus (meaning "quill vertebrae") is a genus of theropod dinosaur. It lived during the Early Cretaceous and its fossils were found on the Isle of Wight in southern England. The type species is C. oweni.

Discovery and naming

The holotype was collected by William Darwin Fox in 1865 and Calamospondylus oweni was described anonymously by amateur paleontologist William D. Fox in 1866 on the basis of a sacrum and associated pelvic elements found on the Isle of Wight in the layers of the Wessex Formation.^[1]

Several authors (e.g. Woodward & Sherborn 1890; Swinton 1936; Steel 1970) regarded Calamospondylus as a nomen nudum for Aristosuchus and therefore based on the same specimen as the Aristosuchus holotype.^{[2] [3] [4]} However, as noted by Naish (2002), size discrepancies between the holotypes of Calamospondylus oweni and Aristosuchus pusillus as well as letters of correspondence between Richard Owen and Reverend William Fox demonstrate that C. oweni is based on a different specimen than Aristosuchus.^{[5] [6]}

A second species, Calamospondylus foxi, was named by Lydekker (1889)^[7] and was moved to a separate genus, Calamosaurus, by Lydekker (1891).

More remains have since been found, including fragmentary vertebrae collected by Kai Bailey in 2014 and specimen NHMUK R.186, a tibia. Both specimens are on display at the Dinosaur Expeditions, Conservation and Palaeoart Centre near Brighstone, Isle of Wight.

Specimen NHMUK R.186

NHMUK R.186 was discovered by William D. Fox in 1865 or 1866 and was first assigned to Hypsilophodon foxii by Lydekker (1888).^[8] Lydekker (1891) moved NHMUK R.186 to Aristosuchus pusillis,^[9] and Galton (1973) agreed with this classification.^[10] Welles & Long (1974) referred it to the Ornithomimidae,^[11] while Norman (1990), Kirkland et al. (1998) and Long and Molnar (1998) referred NHMUK R.186 to Coelurosauria.^{[12] [13] [14]} Galton and Molnar (2005) noted the similarities of NHMUK R.186 to the holotype of Coelurus fragilis,^[15] and Allain et al. (2014) agreed with the placement of NHMUK R.186 within Coelurosauria.^[16]

Naish et al. (2001) tentatively referred the tibia to Calamosaurus foxi, and NHMUK R.186 has since been moved to Calamospondylus oweni.^[17]

Description

As a possible oviraptorosaurian, Calamospondylus would have been a small, agile, bipedal carnivore. Naish et al. (2001) estimate the living animal would have been around 1- long.^[18]

See also

• Aristosuchus

Notes and References

1. Anonymous (Fox, W.) (1866). "Another new Wealden reptile." The Athenaeum, 2014: 740.
2. A. S. Woodward and C. D. Sherborn. (1890). A Catalogue of British Fossil Vertebrata. Dulao & Company, London 1-396.
3. Swinton, W.E. (1936). The dinosaurs of the Isle of Wight. Proceedings of the Geologists’ Association, 47, 204–220.
4. Steel, R. (1970). Encyclopedia of Paleoherpetology, Part 14: Saurischia. Gustav Fischer Verlag, Stuttgart.
5. Naish, D. (2002). The historical taxonomy of the Lower Cretaceous theropods (Dinosauria) Calamospondylus and Aristosuchus from the Isle of Wight. Proceedings of the Geologists' Association 113: 153-163.
6. Naish, D. (2011). Theropod dinosaurs. In Batten, D. J. (ed.) English Wealden Fossils. The Palaeontological Association (London), pp. 526–559.
7. Lydekker . R. . 1889 . VIII.—On a Cœluroid Dinosaur from the Wealden . Geological Magazine . 6 . 3 . 119–121 . 10.1017/s0016756800176149 . 0016-7568.
8. Book: Lydekker, Richard . Catalogue of the fossil Reptilia and Amphibia in the British Museum (Natural history) ... By Richard Lydekker ... . 1888 . Printed by order of the Trustees . London.
9. Lydekker . R. . 1891 . On certain Ornithosaurian and Dinosaurian Remains . Quarterly Journal of the Geological Society . 47 . 1-4 . 41–44 . 10.1144/gsl.jgs.1891.047.01-04.06 . 0370-291X.
10. Galton, P.M., (1973). A femur of a small theropod dinosaur from the Lower Cretaceous of England. Journal of Paleontology, 47, 996-997.
11. Welles, S.P., Long, R.A., (1974). The tarsus of theropod dinosaurs. Annals of the South African Museum, 64, 191-218.
12. Norman, D.B., (1990). Problematic Theropoda: “Coelurosaurs”. In: Weishampel, D.B., Dodson, P., Osmolska, H. (eds.). The Dinosauria. Berkeley, University of California Press, 280-305.
13. Kirkland . J.I. . Britt . B.B. . Whittle . C.H. . Madsen . S.K. . Burge . D.L. . 1998 . A small coelurosaurian theropod from the Yellow Cat Member of the Cedar Mountain Formation (Lower Cretaceous, Barremian) of eastern Utah . New Mexico Museum of Natural History and Science Bulletin . 14 . 239–248.
14. Long, J.A. and Molnar, R.E. (1998). "A new Jurassic theropod dinosaur from Western Australia". Records of the Western Australian Museum 19 (1): 221-229
15. Galton, P.M., Molnar, R.E., (2005). Tibiae of small theropod dinosaurs from Southern England: from the Middle Jurassic of Stonesfield near Oxford and the Lower Cretaceous of the Isle of Wight. In: Carpenter, K. (ed.). The carnivorous dinosaurs. Bloomington and Indianapolis, Indiana University Press, 3-22
16. Allain . R. . Vullo . R. . Le Louff . J. . Tournepiche . J-F. . 2014 . European ornithomimosaurs (Dinosauria, Theropoda): an undetected record . Geologica Acta . 17 . 10.1344/105.000002083 . 1695-6133. free .
17. Web site: Down on the (former) Dinosaur Farm . 23 October 2023 . Love in the Time of Chasmosaurs.
18. Naish, D., Hutt, S., and Martill, D.M. (2001). Saurischian dinosaurs 2: theropods. In: Martill, D.M., and Naish, D. (eds.). Dinosaurs of the Isle of Wight. The Palaeontological Association:London, 242-309.