Coelurus
| Coelurus | ||||||||||
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Coelurus fragilis , living reconstruction with hypothetical fletching |
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| Temporal occurrence | ||||||||||
| Upper Jurassic ( Kimmeridgian ) | ||||||||||
| 157.3 to 152.1 million years | ||||||||||
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| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Coelurus | ||||||||||
| Marsh , 1879 | ||||||||||
| Art | ||||||||||
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Coelurus is a theropod dinosaur belonging to the Coelurosauria group . It is a small, graceful, bipedal carnivore, the remains of which were found in the layers of the Morrison Formation ( Kimmeridgian , middle Upper Jurassic) in the area of the northwestern United States . The only species currently assigned to this genus is Coelurus fragilis .
features
Coelurus was about 2 m long and 20 kg heavy. Compared to the related Ornitholestes , the neck and body are generally more elongated. The skull, which is just as small as that of Ornitholestes , is slimmer and more delicate - although no more precise statements can be made, since only a part of the lower jaw of the skull is known.
Finds and find history
Coelurus was the first small theropod to be discovered in the Morrison Formation - it was described by Othniel Charles Marsh as early as 1879 . Today we know of other small thermopods who shared the habitat with Coelurus and are probably more closely related: Ornitholestes hermanni , Koparion douglassi and the Tanycolagreus topwilsoni described in 2005 . Another find is called Elaphrosaurus sp. , and another new genus was mentioned but not yet named (Makovicky, 1997). (Status 2005, see literature).
The first skeleton was discovered in "Reed's Quarry 13" in Como Bluff , one of the most famous dinosaur cemeteries in the world. The bones were recovered over a period of several years. Because of the hollowness of the vertebrae Marsh named the find Coelurus fragilis , which means something like "delicate hollow tail". Later, in 1884, more material was discovered in the same quarry. Marsh attributed the find to a new Coelurus species and named it Coelurus agilis in a brief description . It was made clear much later (Ostrom, 1980) that the two finds are different parts of the same individual.
Four years later, in 1884, Marsh named another Coelurus species after sparse remains (a claw and teeth) found in the Early Cretaceous Potomac Formation in Maryland . The find, known today as "Coelurus" gracilis , could belong to a dromaeosaurid - a membership to Coelurus is excluded today.
literature
- Kenneth Carpenter , Clifford Miles, John H. Ostrom , Karen Cloward: Redescription of the Small Maniraptoran Theropods Ornitholestes and Coelurus from the Upper Jurassic Morrison Formation of Wyoming. In: Kenneth Carpenter (Ed.): The Carnivorous Dinosaurs. Indiana University Press, Bloomington IN et al. a. 2005, ISBN 0-253-34539-1 , pp. 49-71, online (PDF; 3.09 MB) ( Memento of September 27, 2007 in the Internet Archive ).
Individual evidence
- ^ Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ u. a. 2010, ISBN 978-0-691-13720-9 , p. 124, online .
- ^ Othniel Charles Marsh : Principle characters of American Jurassic dinosaurs. Part 8: The Order Theropoda. In: American Journal of Science . Series 3, Vol. 27, No. 160, pp. 329-340, doi: 10.2475 / ajs.s3-27.160.329 .