File:Polycotylid.jpg
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Summary[edit]
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Partial skeleton of a short-necked polycotylid plesiosaur on display in the Museum of the Rockies in Bozeman, Montana. This specimen was collected in Yellowstone County, Montana. Plesiosauria are marine lizards (NOT dinosaurs) which first appeared about 199.6 million years ago. Widespread and numerous, they died off with the rest of the large animals on Earth 66 million years ago in a mass extinction event. They are among the first fossils ever recognized as such, way back in 1605 AD! All Plesiosauria had short, thick bodies; short, thick tails; and four large flippers. Where they differed was in the neck. There are at least three sub-orders: Bobosaura, Plesiosauroidea, and Pliosauroidea. Among the Plesiosauria is the family, Plesiosauridae. A "node" of this family is the Cryptoclidia. No one is sure just how the Cryptoclidia relate to the Plesiosauridae family, but they do. Thus, this is a "node" and not a new family or new suborder. A node off the Cryptoclididae is the Leptocleidia, and a family of the Leptocleidia is the Polycotylidae. The Polycotylidae had very short necks, but very elongated heads. In this respect, they looked like pliosaurs. But looks are deceiving: In the actual structure of their bodies, they are far closer to the Plesiosauridae. Because key skeletal elements of this Polycotylidae are missing, the species is "indet" (Indeterminate). |
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| Author | Tim Evanson from Washington, D.C., United States of America |
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This image, originally posted to Flickr, was reviewed on 21 July 2013 by the administrator or reviewer File Upload Bot (Magnus Manske), who confirmed that it was available on Flickr under the stated license on that date. |
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
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| current | 11:44, 21 July 2013 | | 3,000 × 847 (2.15 MB) | File Upload Bot (Magnus Manske) (talk | contribs) | Transferred from Flickr by User:FunkMonk using flickr2commons |
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