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, May 2007 by Naish, Darren, Martill, David M

Abstract:

Beginning with Buckland's 1824 description of Megalosaurus, the Geological Society of London played a leading role during the 19th century discovery of dinosaurs in Britain. Here we review the society's role and assess the current knowledge of saurischian dinosaurs in the country. Of Britain's 108 dinosaur species (excluding nomina nuda and objective synonyms), 32% have been named in the pages of Society publications. Britain has a rich and diverse dinosaur record ranging from the Rhaetian to the Cenomanian, and includes a surprising taxonomic diversity. Alleged Lower and Middle Triassic dinosaurs from Britain are suspect or erroneous. Sauropodomorphs represent all of the major clades and several have their earliest global appearances in the British record (Diplodocoidea, Rebbachisauridae and Titanosauria), implying that this region was biogeographically important for this group. The British theropod record is diverse, and includes the earliest spinosaurids, carcharodontosaurids and coelurosaurs. Although some specimens are represented by near-complete skeletons, much material is fragmentary and indeterminate, and c. 54% of British dinosaur taxa are considered nomina dubia. In part this high number results from the genesis of dinosaur science in Britain and the corresponding obsolescence of supposedly diagnostic characters.

Dinosaure were first described by 19th century British scientists working on fossils discovered in England (e.g. Torrens 1997, and references therein), and the Geological Society of London played a pivotal role in establishing the scientific study of dinosaurs. With an emphasis on the role of the Society, we here review the history, geological occurrence and systematics of British dinosaurs.

In 1824, William Buckland announced the discovery of Megalosaurus from the Stonesfield Slate of Oxfordshire (Buckland 1824). This seminal paper includes the first scientific description (Fig. 1) of the animals that later became the Dinosauria (Owen 1842). Although many early papers were often little more than descriptions of isolated bones or teeth, they set the foundation for what was to become one of the most popular strands of vertebrate palaeontology. In the latter half of the 19th century, the Quarterly Journal of the Geological Society of London became the leading journal in which studies on British dinosaurs were published. A remarkable 35 dinosaur taxa, representing 32% of the 108 dinosaure that we recognize as valid or as nomina dubia, have been named in Society publications. (A list of these taxa is available online at http://www.geolsoc.org.uk/SUPl 8267. A hard copy can be obtained from the Society Library.) Although we include Aves within Dinosauria, we have restricted our listing to the Mesozoic. Because many British dinosaur finds have been highly incomplete, many taxa have been erected on material now considered inadequate. What were regarded as species-defining characters (autapomorphies in modern parlance) have turned out to be characters defining larger groups (synapomorphies in modern parlance); to adapt the term of Wilson & Upchurch (2003), they have become obsolete features.

Despite the fragmentary nature of much British dinosaur material, and the fact that many names based on this material are now considered nomina dubia, it remains of scientific value in

that much of it is diagnostic at higher taxonomic levels. Even fragmentary remains can provide important data on the occurrence and distribution of clades. However, it is misleading to imply that all British dinosaur taxa, or all of those erected within Society publications, were erected for poor specimens. Some of the best represented and best known British dinosaurs (Hypsilophodon foxii Huxley 1869, Cumnoria prestwichii (Hulke, 188Oa) and Mantellisaurus atherfieldensis (Hooley, 1925)) were published in the Quarterly Journal.

Dinosaur localities in Britain

Here we present a brief summary of the dinosaur-bearing strata and localities in Britain. General locality maps are available in the Supplementary Publication (see p. 000).

Upper Triassic dinosaur localities

Several suspect or erroneous discoveries have been claimed from the Lower and Middle Triassic, but the oldest British forms are probably Rhaetian. These include, in the Bristol district, abundant remains of the basal sauropodomorph Thecodontosaurus (Benton et al. 2000), and in South Wales, coelophysoid and Thecodontosaurus material from the Vale of Glamorgan (Kermack 1984; Fraser 1994; Rauhut & Hungerbiihler 2000; Yates 2003). Thecodontosaurus material has also been reported from an unspecified location in Avon (Yates 2003), and from the Westbury Formation of Newark-Upon-Trent, Nottinghamshire (Martill & Clarke 1994). The latter record is erroneous, however, and should be regarded as Archosauria indet. Other reports of the taxon from Somerset and Gloucestershire (Storrs 1994) lack the diagnostic characters of Thecodontosaurus and should be regarded as Sauropodomorpha indet.