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On the first partial skull of an ankylosaurian dinosaur from the Lower Cretaceous of the Isle of Wight, southern England

Published online by Cambridge University Press:  01 May 2009

David B. Norman  and
Tamsin Faiers
David B. Norman
Affiliation:
Sedgwick Museum of Geology, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
Tamsin Faiers
Affiliation:
Sedgwick Museum of Geology, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
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Abstract

The specimen is identified as the partial cranium of a nodosaurid ankylosaur (Ornithischia: Thyreophora) on the basis of the presence of bone which is fused to the dorsal surface of the skull and has secondarily closed the upper temporal fenestrae. The only unequivocally nodosaurid material recovered from the Isle of Wight to date comes from Wealden facies, and has been referred to the genus Polacanthus; it is considered highly probable that this new skull is referable to the same genus. Despite having undergone abrasion, through post-emergence water-rolling, the skull and cranial walls have proved to be relatively informative of the general anatomy of the braincase and the neural and vascular anatomy of this part of the head. The anatomy of the braincase of most ankylosaurs (with the notable exception of the juvenile specimens of the ankylosaurid Pinacosaurus) is surprisingly poorly known, despite the relative abundance of cranial material in North American and Asian collections.

The cranial neural and vascular anatomy is well shown in this specimen and enables the first detailed description of nodosaurid endocranial structures. The general form of the brain can be outlined from the structure of the endocast and the principal lobes can be identified; the majority of the cranial nerves have been identified, and a significant component of the associated vascular system is also visible. In most respects the endocast shows a neural anatomy which is common to that known in most dinosaurs. When compared to their nearest relatives, the ankylosaurid ankylosaurs (Euoplocephalus), the nodosaurid endocranial cast shows a more pronounced cerebral flexure, a forebrain which is broader and more expanded dorsally, and a more prominent cerebellum (although there is no evidence for a floccular lobe); there are minor differences in the arrangement of the cranial nerves, and the dorsal portions of the vascular system are better shown.

Because of erosion, the olfactory lobes of this specimen of cf. Polacanthus are not preserved, and cannot be compared to those of ankylosaurid ankylosaurs; the latter are unusual in the strong separation of the lobes (reflected in the divergent olfactory stalks); this feature may be associated with the very complex passages within the nasal region of the skull, which are lacking in the nodosaurids described to date.

Type
Articles
Information
Geological Magazine , Volume 133 , Issue 3 , May 1996 , pp. 299 - 310
Copyright
Copyright © Cambridge University Press 1996

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References

Anonymous. 1865. A new Wealden dragon. Order Sauria; family Dinosaurian; Genus Polacanthus; Species foxii. Illustrated London News 47(16 09 1865), 270.Google Scholar
Bauchot, R., 1978. Encephalisation in vertebrates: a new mode of calculation for allometry coefficients and isoponderal indices. Brain Behaviour and Evolution 15, 1–18.CrossRefGoogle Scholar
Blows, W. T., 1987. The armoured dinosaur Polacanthus foxi, from the Lower Cretaceous of the Isle of Wight. Palaeontology 30, 557–80.Google Scholar
Bruner, H. L., 1907. On the cephalic veins and sinuses of reptiles with description of a mechanism of raising the venous blood pressure in the head. American Journal of Anatomy 7, 1–117.CrossRefGoogle Scholar
Coombs, W. P., 1978 a. An endocranial cast of Euoplocephalus (Reptilia: Ornithischia). Palaeontographica Abteilung A 161, 176–82.Google Scholar
Coombs, W. P., 1978 b. The families of the ornithischian dinosaur Order Ankylosauria. Palaeontology 21, 143–70.Google Scholar
Coombs, W. P., & Maryanska, T., 1990. Ankylosauria. In The Dinosauria (eds Weishampel, D. B., Dodson, P. and Osmolska, H.), pp. 456–83. Berkeley: University of California Press.Google Scholar
de Beer, G. R., 1937. The development of the vertebrate skull, 1st ed. Oxford: Oxford University Press.Google Scholar
Delair, J. B., 1982. Notes on an armoured dinosaur from Barnes High, Isle of Wight. Proceedings of the Isle of Wight Natural History and Archaeological Society 7(5), 297–302.Google Scholar
Dendy, A., 1909. The intracranial vascular system of Sphenodon. Philosophical Transactions of the Royal Society of London, Series B 200, 403–26.Google Scholar
Dendy, A., 1910. On the structure, development and morphological interpretation of the pineal organs and adjacent parts of the brain of the tuatara (Sphenodon). Philosophical Transactions of the Royal Society of London, Series B 201, 227–331.Google Scholar
Fürbringer, M., 1897. Üiber die spino-occipitalen Nerven der Selachier und Holocephalen und ihre vergleichende Morphologie. In Gegenbaurs-Festschrift, pp. 351–788. Leipzig: W. Engelmann.Google Scholar
Galton, P. M., 1990. Stegosauria. In The Dinosauria (eds Weishampel, D. B., Dodson, P. and Osmolska, H.), pp. 435–55. Berkeley: University of California Press.Google Scholar
Hopson, J. A., 1979. Paleoneurology. In The Biology of the Reptilia (eds Northcutt, R. G. and Ulinski, P.), pp. 39–146. London: Academic Press.Google Scholar
Hopson, J. A., 1980. Relative brain size in dinosaurs. In A cold look at the warm blooded dinosaurs (eds Thomas, R. D. K. and Olson, E. C.), pp. 287–310. Boulder, Colorado: AAAS/Westview Press.Google Scholar
Jerison, H. J., 1969. Brain evolution and dinosaur brains. American Naturalist 103, 575–88.CrossRefGoogle Scholar
Jerison, H. J., 1973. Evolution of the brain and intelligence. New York and London: Academic Press.Google Scholar
Lucas, F. A., 1902. A new generic name for Stegosaurus marshi. Science 16, 435.CrossRefGoogle Scholar
Mantell, G. A., 1833. The geology of the South East of England, 1st ed. London: Longman, Rees, Orme, Brown, Green & Longman.CrossRefGoogle Scholar
Marsh, O. C., 1895. On the affinities and classification of the dinosaurian reptiles. American Journal of Science (Series 3) L(50), 483–98.CrossRefGoogle Scholar
Martin, V., & Buffetaut, E., 1992. Les Iguanodons (Ornithischia — Ornithopoda) du Crétacé Inferieur de la region de Saint Divier (Haut-Marne). Revue de Paléobiologie 11, 67–96.Google Scholar
Maryanska, T., 1977. Results of the Polish—Mongolian palaeontological expeditions. Part VII. Ankylosauridae (Dinosauria) from Mongolia. Palaeontologia Polonica 37, 85–151.Google Scholar
Nopcsa, F. B., 1915. Die dinosaurier der Siebenbürgenischen Landsteile Ungarns. Mitteilungen aus dem Jahrbuch der Ungarsichen Geologischen Reichsanstalt Budapest 23, 3–24.Google Scholar
Nopcsa, F. B., 1917. Über Dinosaurier. 1: Notizen über die Systematik der Dinosaurier. Zentralblat für Mineralogie, Geologie und Paläontologie 1917, 203–13.Google Scholar
Nopcsa, F. B., 1928. Palaeontological notes on reptiles. Geologica Hungarica, Palaeontological series 1(1), 1–84.Google Scholar
Norman, D. B., 1984. A systematic reappraisal of the reptile order Ornithischia. In Proceedings of the Third Symposium on Mesozoic Terrestrial Ecosystems (eds Reif, W.-E. and Westphal, F.), pp. 157–62. Tübingen: Attempto Verlag.Google Scholar
Norman, D. B., 1987. Wealden dinosaur biostratigraphy. In Fourth Symposium on Mesozoic Terrestrial Ecosystems, short papers (eds Currie, P. J. and Koster, E. H.), pp. 161–6. Drumheller: Tyrrell Museum of Palaeontology.Google Scholar
Norman, D. B., & Weishampel, D. B., 1990. Iguanodontidae and related Ornithopoda. In The Dinosauria (eds Weishampel, D. B., Dodson, P. and Osmolska, H.), pp. 510–33. Berkeley: University of California Press.Google Scholar
O'Donoghue, C. H., 1921. The blood vascular system of the tuatara. Philosophical Transactions of the Royal Society of London, Series B 210, 175–252.Google Scholar
Oelrich, T. M., 1956. The anatomy of the head of Ctenosaura pectinata (Iguanidae). Miscellaneous Publications of the Museum of Zoology, University of Michigan, 94, 1–122.Google Scholar
Osborn, H. F., 1923. Two Lower Cretaceous Dinosaurs from Mongolia. American Museum Novitates 95, 1–10.Google Scholar
Ostrom, J. H., 1961. Cranial morphology of the hadrosaurian dinosaurs of North America. Bulletin of the American Museum of Natural History 122, 33–186.Google Scholar
Owen, R., 1842. Report on British Fossil Reptiles. Part 2. Report of the British Association for the Advancement of Science (Plymouth) 11, 60–204.Google Scholar
Pereda-Suberbiola, J., 1993. Hylaeosaurus, Polacanthus and the systematics and stratigraphy of Wealden armoured dinosaurs. Geological Magazine 130, 767–81.CrossRefGoogle Scholar
Pereda-Suberbiola, J., 1994. Polacanthus (Ornithischia, Ankylosauria), a transatlantic armoured dinosaur from the Early Cretaceous of Europe and North America. Palaeontographica Abteilung A 232, 133–59CrossRefGoogle Scholar
Rawson, P. F., Currey, D., Dilly, F. C., Hancock, J. M., Kennedy, W. J., Neale, J. W., Wood, C. J., & Worssam, B. C., 1978. A correlation of Cretaceous rocks in the British Isles. Geological Society of London. Special Report 9, 1–70.Google Scholar
Romer, A. S., 1956. Osteology of the Reptiles, 1st ed. Chicago: Chicago University Press.Google Scholar
Seeley, H. G., 1887. On the classification of the fossil animals commonly named Dinosauria. Proceedings of the Royal Society of London 43, 165–71.Google Scholar
Sereno, P. C., 1984. The phylogeny of the Ornithischia: a reappraisal. In Proceedings of the Third Symposium on Mesozoic Terrestrial Ecosystems (eds R. W.-E., and Westphal, F.), pp. 219–226. Tübingen: Attempto Verlag.Google Scholar
Sereno, P. C., 1986. Phylogeny of the bird-hipped dinosaurs. National Geographic Research 2, 234–56.Google Scholar
Sereno, P. C., & Dong, Z., 1992. The skull of the basal stegosaur Huayangosaurus taibaii. Journal of Vertebrate Paleontology 11, 318–13.CrossRefGoogle Scholar
Starck, D., 1979. Cranio-cerebral relations in recent reptiles. In Biology of the Reptilia (eds Northcutt, R. G. and Ulinski, P.), pp. 1–38. London: Academic Press.Google Scholar
Stewart, D. J., 1981. A field guide to the Wealden Group of the Hastings area and Isle of Wight. In Field Guides to modern and ancient fluvial systems in Britain and Spain, International Fluvial Conference (ed. Elliott, T.), pp. 1–31. Keele: University of Keele, Department of Geology.Google Scholar
Thulborn, R. A., 1994. Mimicry in ankylosaurid dinosaurs. Records of the South Australian Museum 27(2), 151–8.Google Scholar
Tumanova, T. A., 1987. The armored dinosaurs of Mongolia. The Joint Soviet—Mongolian Paleontological Expedition 32, 1–80.Google Scholar