An unusual new neosauropod dinosaur from the Lower Cretaceous Hastings Beds Group of East Sussex,...

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Transcript of An unusual new neosauropod dinosaur from the Lower Cretaceous Hastings Beds Group of East Sussex,...

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An unusual new neosauropod dinosaur from the Lower Cretaceous Hastings Beds Group of East Sussex, England Michael P. Taylor and Darren Naish School of Earth and Environmental Sciences University of Portsmouth Portsmouth PO1 3QL Slide 2 An unusual new neosauropod dinosaur from the Lower Cretaceous Hastings Beds Group of East Sussex, England Michael P. Taylor and Darren Naish School of Earth and Environmental Sciences University of Portsmouth Portsmouth PO1 3QL freaky Slide 3 Where to discover new dinosaurs (I) Mike Benton at SVPCA 2005 suggested countries such as Mongolia and Argentina... Slide 4 Where to discover new dinosaurs (II)... but the best unexplored territory is still the basement of the Natural History Museum. Slide 5 Meet BMNH R2095 A single, partial mid-to-posterior dorsal vertebra. That's not much material, but: Sauropod dorsals are very diagnostic. This specimen is highly apomorphic. Briefly described by Lydekker (1893) when no-one knew anything about sauropods. Subsequently overlooked. Slide 6 Where it's from Precise locality information is not preserved (if it was ever recorded). Lydekker (1893) just said from the Wealden of Hastings. But: known to have been collected by Rufford. Better documented Rufford specimens are known to be from East Cliff and Ecclesbourne Glen (both east of Hastings) R2095 Slide 7 Age Stratigraphic information is not preserved. Units exposed both East Cliff and Ecclesbourne Glen are part of the Ashdown Beds Formation R2095 probably from Ecclesbourne Glen: It is closer to Hastings than is East Cliff Most of Rufford's specimens are from Ecclesbourne Glen. Ashdown Beds Formation exposure at Ecclesbourne Glen is Berriasian R2095 Slide 8 A long-overdue closer look at the specimen Left and right lateral 200 mm Anterior Slide 9 A long-overdue closer look at the specimen Anterior and posterior Slide 10 So what is it? Slide 11 So what is it? 1. Sauropoda Slide 12 So what is it? 2. Eusauropoda Slide 13 So what is it? 3. Neosauropoda Slide 14 So what is it? 4. a unique Neosauropod Slide 15 Similarities between sides Slide 16 Similarities and differences between sides Slide 17 Slide 18 Reconstruction Parapophysis can be identified at junction of laminae. Positions of diapophysis and zygapophyses can be deduced from trajectories of laminae. Condyle curvature inferred from cotyle. High location of parapophysis indicates posterior position. Slide 19 So what kind of Neosauropod is it? Classic diplodocoids (Diplodocidae+ Dicraeosauridae) Rebbachisauridae Titanosauria Brachiosauridae Camarasauridae ? ? Diplodocoidea Macronaria Neosauropoda Slide 20 Is it a classic diplodocoid? Diplodocus carnegii holotype CM 84, dorsal 8 (Hatcher 1901, Plate VII, reversed) Slide 21 Is it a classic diplodocoid? Diplodocus carnegii holotype CM 84, dorsal 8 (Hatcher 1901, Plate VII, reversed) Slide 22 Is it a classic diplodocoid? Diplodocus carnegii holotype CM 84, dorsal 8 (Hatcher 1901, Plate VII, reversed) Slide 23 Is it a rebbachisaur? Rebbachisaurus garasbae holotype, posterior dorsal (photo by Fabio Dalla Vecchia, reversed) Slide 24 Is it a rebbachisaur? Rebbachisaurus garasbae holotype, posterior dorsal (photo by Fabio Dalla Vecchia, reversed) Slide 25 Is it a rebbachisaur? Rebbachisaurus garasbae holotype, posterior dorsal (photo by Fabio Dalla Vecchia, reversed) Laterally diverging prezygapophyses Prezygapophyses close together Slide 26 Is it a camarasaur? Camarasaurus grandis holotype YPM 1901, posterior dorsal (Ostrom & McIntosh 1966, Plate 25) Slide 27 Is it a camarasaur? Camarasaurus grandis holotype YPM 1901, posterior dorsal (Ostrom & McIntosh 1966, Plate 25) Stupid and ugly Stupid and ugly Slide 28 Is it a brachiosaur? Brachiosaurus brancai holotype HMN SII, D7 (Janensch 1950, Figure 56, reversed) Slide 29 Is it a brachiosaur? Brachiosaurus brancai holotype HMN SII, D7 (Janensch 1950, Figure 56, reversed) ? ? ? ? Slide 30 Is it a brachiosaur? Brachiosaurus brancai holotype HMN SII, D7 (Janensch 1950, Figure 56, reversed) ? ? ? ? Slide 31 Is it a titanosaur? Neuquensaurus autralis MCS-5/20-22, D9 (Salgado et al. 2005, Figure 4) Slide 32 Is it a titanosaur? Neuquensaurus autralis MCS-5/20-22, D9 (Salgado et al. 2005, Figure 4) Slide 33 Is it a titanosaur? Internal structure camerate Camellate Neuquensaurus autralis MCS-5/20-22, D9 (Salgado et al. 2005, Figure 4) Slide 34 So what is it? Slide 35 It seems to represent a completely new group (or a very highly derived member of a known group)... what we used to call a new family Slide 36 Centrum proportions are similar to Brachiosaurus brancai holotype HMN SII, D7 B. brancai is estimated 25m long (Paul 1988) If isometrically similar, R2095 would be 15m. B. brancai is estimated 35000 kg (average of several sensible published estimates). R2095 would be 7500 kg. (About the mass of a big elephant) How big was R2095? Slide 37 Longer and lighter if similar to Diplodocus carnegii CM 84 D. carnegii is 27m long and 1200 kg (Wedel 2005). Centrum proportions differ, so: assume length proportional to centrum length => R2095 is 20m long assume mass propotional to centrum length x cotyle height x width => R2095 masses 2300 kg How big was R2095? Slide 38 Pelorosaurus becklesi (actually generically distinct and titanosaurian) Sauropods of the Hastings Beds Group Humerus Ulna Radius Cetiosaurus brevis = Pelorosaurus conybeari (pending ICZN petition) Humerus Slide 39 Sauropod diversity goes nuts! Dorsal vertebrae of Tendaguria tanzaniensis holotype MB.R.2092.1-2, NB4, NB5 (Bonaparte, Heinrich and Wild 2000) Slide 40 Sauropod diversity goes nuts! Agustinia ligabuei Bonaparte 1999 Reconstruction by Mudyryknow J.R., from The Dinosauricon http://dino.lm.com/images/display.php?id=2268 It might be some kind of titanosaur... Slide 41 Sauropod diversity goes nuts! Agustinia ligabuei Bonaparte 1999 Reconstruction by Mudyryknow J.R., from The Dinosauricon http://dino.lm.com/images/display.php?id=2268 It might be some kind of titanosaur...... but Titanosauria is the new Cetiosauridae Slide 42 Sauropod diversity goes nuts! Slide 43 I'd like to thank everyone who's made tonight possible... * My co-author Doctor Darren Naish * Philip James Rufford for finding and donating the specimen * Everyone who's ignored it for 113 years * Sandra D. Chapman (Natural History Museum) for access to the specimen. * Nick Pharris (University of Michigan) for etymological assistance. * We used English translations of several papers from the very useful Polyglot Paleontologist web-site http://ravenel.si.edu/paleo/paleoglot/index.cfm Thanks are due specifically to the following translators: * Sebastin Apestegua (Bonaparte 1999a), * Matthew T. Carrano (Bonaparte 1986b), * William R. Downs (Young and Zhao 1972), * Matthew C. Lamanna (Bonaparte and Coria 1993, del Corro 1975 and Lavocat 1954) * Jeffrey A. Wilson (Salgado and Coria 1993). * In addition, portions of Janensch 1914 were translated by Gerhard Maier. * David M. Martill (University of Portsmouth) reviewed the manuscript. * Mathew J. Wedel (UCMP) reviewed this presentation.