Byronosaurus
| Byronosaurus | ||||||||||||
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Partially preserved skulls of two young animals, shortly before or after hatching (IGM 100/972). |
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| Temporal occurrence | ||||||||||||
| Upper Cretaceous (late Campanium ) | ||||||||||||
| 76.4 to 72 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Byronosaurus | ||||||||||||
| Norell , Mackinovicky and Clark , 2000 |
Byronosaurus is a genus of theropod dinosaur in the family Troodontidae , a group of bird-like Maniraptora . This dinosaur was a small bipedal carnivore whose fossils were found in sedimentary rocks of the Upper Cretaceous (late Campanian ) Mongolia . The only known species ( type species ) is Bryonosaurus jaffei .
description
Byronosaurus reached a length of 1.5 m, a height of 50 cm and a weight of 4 kg - making it one of the smallest known dinosaurs. Like all troodontids, which were probably some of the most intelligent dinosaurs, Byronosaurus had a relatively large brain. Its needle-shaped teeth are very similar to those of Archeopteryx and, unlike all other known troodontids, were not notched. Like his relatives, he probably hunted small animals, his eyes being capable of stereoscopic vision . Unlike his relatives, however, he also had a good sense of smell.
Finds and find history
So far, two partial skeletons have been found, both with skulls. The first (the holotype material IGM 100/983) was discovered in 1993 in Ukhaa Tolgod , a rich fossil site in southern Mongolia. The skeleton was recovered as a collection of loose bones - unlike other fossils from the site, where the bones were often found connected. Nevertheless, a fragment of the skull was recovered. However, later investigations showed that the find was the remains of two different genera of dinosaurs; the bones of an ornithomimid were mixed with those of Byronosaurus . However, the ornithomimid remains (now known as IGM 100/987) are significantly larger and could therefore be easily sorted out.
Byronosaurus was scientifically described by Norell, Mackinovicky, and Clark in 2000 . The generic name as well as the specific epithet honor Byron Jaffe, whose family sponsored paleontological expeditions of the Mongolian Academy of Sciences and the American Museum of Natural History .
Three years after the first find (1996), another find was made six kilometers west of the first site. The skeleton (IGM 100/984) was also attributed to Byronosaurus , since among other things all teeth had no notches . Although the remains are very fragmentary, they show many features that have not been preserved in the holotype material.
literature
- Peter J. Makovicky , Mark A. Norell , James M. Clark , Timothy Rowe : Osteology and Relationships of Byronosaurus jaffei (Theropoda: Troodontidae) (= American Museum Novitates. No. 3402, ISSN 0003-0082 ). American Museum of Natural History, New York NY 2003, online .
Individual evidence
- ^ Alan H. Turner, Diego Pol, Julia A. Clarke, Gregory M. Erickson, Mark A. Norell: A Basal Dromaeosaurid and Size Evolution Preceding Avian Flight. In: Science . Vol. 317, No. 5843, 2007, pp. 1378-1381, doi : 10.1126 / science.1144066 , PMID 17823350 .