Saturday 21 May 2011
Seeley, dinosaurs and divisions...
Harry Govier Seeley gave us something that neither Huxley, Cope nor the infamous Marsh could (but this was not from a want of trying). In 1887 H.G. Seeley gave us the lasting major division within Richard Owen's tribe of beasties, giving us the saurischian and ornithischian dinosaurs. You have already met the tooth and claw of the saurischia ('lizard-hipped') that ultimately gave rise to all birds today. Now this is the rub, the ornithischian ('bird-hipped') dinosaurs have nothing to do with birds, other than being the sister group to the saurischia that did...confused? When folks say, 'Whats in a name', maybe here hindsight would have made Seeley chuckle. His division is robust, but the names often confusing, given each groups evolutionary products...sadly zero for the ornithischian dinosaurs post-Cretaceous. One thing about this group, if you visit the AMNH in New York, you'll get to see some of the most important ornithischian fossils from north America. Here is a brief tour of the said gallery.
Triceratops with its distinct horned face and solid frill has been having a rough ride with its contemporary Torosaurus... identifiable from its larger perforated frill. Jack Horner and colleagues have recently suggested the latter is an adult of the former...'slaying' a species with a stroke...or should I say 'stage' of ontogeny (growth). This is not a new approach to slaying dinosaur species, as Peter Dodson did the same back in 1975 with his analysis of hadrosaur skulls...reducing nine to three species in a stroke. However, folks must have been more careful when naming species since Peter's work back in 1975...or have they? Other palaeontologists have urged caution, such as Mike Benton at Bristol, who also suggests that ~50% of dinosaur species might not be valid! Something to think about when we explore museums, their collections and the barren Badlands when hunting 'new' species...or maybe just another growth stage. Lets just say, we must be careful when naming new species of dinosaurs.
However, my favourite fossil in this gallery is not something horny from the Cretaceous, but wrinkled hadrosaur (Edmontosaurus) that looks like it overstayed its welcome at a sun-bathing contest. This 'beautiful' fossil was dug-up by the royal-family of palaeontology collectors, the Sternberg's...as this was a family of fossil hunters extraordinaire!
When you stand above this remarkable dinosaur, with its arms and legs wide open and its chest caved in...it looks almost too incredible to be 65 million years old, but that is exactly what it is, incredible and 65 million years old! What is most amazing for me, Charles Sternberg and his two sons prepared the fossil, as you see it today, while still in the Badlands of Wyoming.
When dinosaurs are not fully grown, they really can fool us...this skeleton has been given several names in the past, but now most agree it is either a juvenile Lambeosaurus or Corythosaurus! This is possibly why our research group has concentrated on understanding more about the preservation, biomechanics and anatomy of these enigmatic beasties. I shall add some more on my visit to the AMNH ornithischian gallery soon!
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Ah yes, the "torosaurus vs. triceratops" issue. I personally don't get why everyone got so hyped up over it. Triceratops was in no danger of disappearing, just some lame dinosaur they had never heard of. In fact, you probably would never have heard of torosaurus unless you had paid attention whilst watching Walking With Dinosaurs.
ReplyDeleteThank you for your wonderful photos from AMNH. I am an education volunteer in the fossil halls and an explainer at the temporary exhibit, The World's Largest Dinosaurs, which I hope you will have time to visit. It is really a fantastic show! Posts such as yours help encourage readers to visit the Museum themselves and enjoy our displays.
ReplyDeleteOne small nit-pick: our T.rex, AMNH 5027, is not the holotype. That resides at the Carnegie Museum of Natural History, CM 9380. The story from our end is that we sold it in Dec., 1941, after Pearl Harbor, because of fear of German bombing of NYC. But a label at the Carnegie states that the purchase arrangements were made in Jan., 1941. If you did not already see their renovated dino halls at last year's SVP, go to Pittsburgh now. They are stunning!
Neal L. Larson's chapter in Peter Larson & Kenneth Carpenter's Tyrannosaurus Rex: The Tyrant King (my source) is a great detailed survey of every single T.rex skeleton in existence.
Seeley's names are essential but always necessitate an explanation for curious visitors who sometimes wonder why Jurassic and Cretaceous species are side by side in each hall. Another nomenclature issue is sauropod, since there is nothing uniquely lizard-like about the pes and manus of Apatosaurus.
Edmontosaurus is wonderful in another way. It is clearly a complete, original fossil. The most common question in the halls is "Are these real?" Most of the bones on display are the actual fossils and, strangely, many visitors do not become really involved with the exhibits until assured they are genuine and not casts or sculpts.
I hope you also have some pics of the Hall of Vertebrate Origins and of Mammals and Their Extinct Relatives. They are sometimes a bit under-visited because of the popularity of the adjacent dinos but are wonderful in their own right.
oops! My mistake, I have confused AMNH 973 (CM9380) and AMNH5027 in the past...its the Brown connection and proximity in time of collection. It is a pity that Osborn never got his second mount up on display to have both specimens in a dynamic pose together. I must stop writing my blog when in a rush or with no access to references...my brain can misfire occasionally. The AMNH halls remain of of my favourite places to walk with dinosaurs in the world. I shall be bringing a group to see the sauropod exhibition soon...and to see if Mark Norell ended-up using one of my images of titanosaur sauropod trackways from Spain in the exhibit.
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