The Middle and Late Jurassic theropod (Dinosauria: Archosauria) record of Britain is reviewed to support the inclusion of taxa from these time periods in a new cladistic analysis constructed to elucidate basal tetanuan relationships. British Middle Jurassic deposits have yielded the most abundant theropod fossil material of this age world-wide. The most productive British theropod localities of this epoch are Bathonian in age: Stonesfield, Oxfordshire and New Park Quarry, Gloucestershire. The large-bodied theropod assemblages of these localities are interpreted as monospecific. Abundant remains from these localities can be referred to <i>Megalosaurus,</i> the historically oldest dinosaur taxon. Two additional large-bodied tetanurans were present in British Bathonian Dinosaur ecosystems based on more fragmentary fossils. A minimum of two further, small-bodied taxa are indicated by teeth and postcranial remains. The British Late Jurassic strata are less productive but yield new data that contribute toward global biogeographic scenarios. <i>Metriacanthosaurus </i>(Oxfordian) is a sinraptorid allosauroid, <i>Stokesosaurus </i>(Tithonian) is a basal tyrannosauroid, and isolated remains of robust, large-bodied theropods (Kimmeridgian-Tithonian) show affinities with <i>Megalosaurus </i>or its sister taxon <i>Torvosaurus.</i> A new cladistic analysis focussing on basal tetanuran relationships includes 213 characters (of which 22 are new) and 41 taxa. Several of these taxa have never been included in a cladistic analysis: <i>Chuandongocoelurus, Marshosaurus, Piveteaursaurus, ‘Megalosaurus’ hesperis </i>and <i>Magnosaurus nethercombensis. </i>The content of groups within Spinosauroidea corresponds well with geography, indicating limited endemism across Pangaea among theropods of this age. Most Late Jurassic large-bodied theropods are allosauroids, and allosauroids are also abundant during this time period. This suggests faunal turnover between the Middle and Late Jurassic.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:596577 |
| Date | January 2009 |
| Creators | Benson, R. B. J. |
| Publisher | University of Cambridge |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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