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Sphenospondylus

Seeley, 1883 Nomen dubium

From Greek 'sphen' ('wedge') and 'spondylos' ('vertebra'), for the wedge-shaped base of the compressed centra.

Sphenospondylus is a dubious genus of iguanodontian ornithopod dinosaur from the Early Cretaceous Wealden of the Isle of Wight, England. Seeley (1883) erected the genus on a short series of dorsal vertebrae without naming a species, and Lydekker (1888) later added the epithet gracilis. The material cannot be diagnosed or associated with any other taxon, so the name is treated as a nomen dubium.

Species

Sphenospondylus gracilis Lydekker, 1888 Nomen dubium

Type species

Holotype
NHMUK PV R 142 , Natural History Museum
Material
Series of six incomplete dorsal vertebrae, the centra strongly compressed laterally and the neural arches depressed.
Notes
Seeley (1883) founded the genus on a series of six vertebrae in the Woodwardian Museum at Cambridge and declined to name a species, writing of refraining from doing so pending the question of whether the material belonged with Iguanodon seelyi. Lydekker (1888) added the epithet gracilis, and White (1973) and McDonald (2012) both give the type of that species as the London specimen.
Horizon
Early Cretaceous
Locality
Brook, Isle of Wight, Isle of Wight, United Kingdom Seeley (1883) records no provenance for the holotype, R142, in the Fox Collection; Seeley suspects many of its vertebrae belonged to the same individual as the Brook material the genus was founded on, and that inference is what places it at Brook. Norman (2013) maps the upper Wessex Formation against the base of the Vectis Formation along this stretch of coast, so the unit would be the Wessex if the attribution holds.

References

  1. Seeley, H. G. (1883). On the dorsal region of the vertebral column of a new dinosaur (indicating a new genus, Sphenospondylus), from the Wealden of Brook in the Isle of Wight, preserved in the Woodwardian Museum of the University of Cambridge. Quarterly Journal of the Geological Society of London 39: 55-61. Geological Society of London.

    Erects the genus on six dorsal vertebrae from the Wealden of Brook, Isle of Wight, without naming a species.

    seeley1883b
  2. Lydekker, R. (1888). Note on a new Wealden iguanodont and other dinosaurs. Quarterly Journal of the Geological Society of London 44(173): 46-61. doi:10.1144/gsl.jgs.1888.044.01-04.08

    Proposes the species epithet gracilis for Seeley's genus, since Seeley "has not applied a specific name to the type".

    lydekker1888b
  3. Lydekker, R. (1888). Catalogue of the Fossil Reptilia and Amphibia in the British Museum (Natural History). Part I. British Museum (Natural History), London 1-309.

    Catalogs the species, citing the Quarterly Journal note for the name.

    lydekker1888a
  4. Norman, D. B. (1986). On the anatomy of Iguanodon atherfieldensis (Ornithischia: Ornithopoda). Bulletin de l'Institut Royal des Sciences Naturelles de Belgique, Sciences de la Terre 56: 281-372.

    Judges the material an indeterminate series of dorsal vertebrae.

    norman1986a
  5. White, T. E. (1973). Catalogue of the genera of dinosaurs. Annals of Carnegie Museum 44: 117-155. doi:10.5962/p.243870

    Gives the type of the type species as BMNH R142, several dorsal vertebrae from the Wealden of the Isle of Wight.

    white1973a
  6. Norman, D. B. (2004). Basal Iguanodontia. The Dinosauria, Second Edition (Weishampel, D. B.; Dodson, P.; Osmólska, H., eds.) 413-437. University of California Press, Berkeley.

    Lists the species inside the Iguanodon atherfieldensis synonymy, a reading later withdrawn.

    norman2004a
  7. McDonald, A. T. (2012). The status of Dollodon and other basal iguanodonts (Dinosauria: Ornithischia) from the upper Wealden beds (Lower Cretaceous) of Europe. Cretaceous Research 33(1): 1-6. doi:10.1016/j.cretres.2011.03.002

    Finds the type undiagnostic and not associable with any other taxon, and treats the species as a nomen dubium.

    mcdonald2012b
  8. Norman, D. B. (2013). On the taxonomy and diversity of Wealden iguanodontian dinosaurs (Ornithischia: Ornithopoda). Revue de Paléobiologie, Genève 32(2): 385-404.

    Records the dubious status of the species alongside Vectisaurus valdensis and Proplanicoxa galtoni.

    norman2013a