Shaochilong
Artistic representation of a live Shaochilong, eating at a Sinornithomimus carcass.
China, Inner Mongolia ( Ulansuhai Formation)
- Shaochilong maortuensis ( Hu, 1964)
Shaochilong is a genus theropod dinosaur from the group of Carcharodontosauridae. The so far only find, a very fragmentary skeleton, is from the Upper Cretaceous ( Turonian ) of the Chinese province of Inner Mongolia. This finding has already been described by Hu (1964 ) as a kind of Chilantaisaurus ( Chilantaisaurus maortuensis ) for the first time. However, Stephen Brusatte and colleagues ( 2009) described the find as an independent genus.
Features
Shaochilong was a relatively short stature Carcharodontosauridae with a comparatively short muzzle. The skeleton found probably belonged to a full-grown or nearly full-grown individual. Its length is estimated to be 5 to 6 meters, based on the length of the row of teeth in the upper jaw. The femur is estimated to 61.5 centimeters in length, which indicates a weight of approximately 500 kilograms. A unique feature ( autapomorphy ) of this genus is a small sagittal crest, an about 10 millimeter high, sharp ridge on the center line of the skull, from the paired frontal bone ( frontal ) is formed. Sagittalkämme have so far been detected only in representatives of Coelurosauria.
Palaeobiogeography
Shaochilong is the first undoubted representatives of Carcharodontosauridae, which was discovered in Asia. His discovery allows conclusions on the global development of faunas during the Cretaceous period. So the Carcharodontosauridae were probably distributed worldwide ( cosmopolitan ), and missing only in Australia and Antarctica, two continents, whose fossil record is very patchy. In addition, this finding shows that Asia was the time of Turoniums no longer isolated from other continents, but that could take place already a faunal exchange.
System
Shaochilong is a representative of Carcharodontosauridae, a group within the Carnosauria. A phylogenetic analysis comes to the conclusion that Shaochilong belongs to the derived ( advanced ) Carcharodontosauridae, so do not stand at the base of the family tree of this group. He was more closely related than species from Europe and North America ( as Neovenator and Acrocanthosaurus ) with genera from South America and Africa ( Giganotosaurus, Mapusaurus, Tyrannotitan and Carcharodontosaurus ). The contemporary, but much larger Chilantaisaurus is also attributed to the Carcharodontosauridae, but belongs to a primitive subgroup ( the Neovenatoridae ). The finding that two representatives of the Carcharodontosauridae occur next to each other during the mid-Cretaceous time, is an indication that the Carnosauria at this time in the northern continents ( Laurasia ) are still been the dominant Theropodengruppe, and that the tyrannosaur only in the late Cretaceous to predominant group were.
Neovenator
Acrocanthosaurus
Shaochilong
Tyrannotitan
Carcharodontosaurus
Giganotosaurus
Mapusaurus
Relationships of Shaochilong, after Brusatte and colleagues, 2009
Fund and naming
The only Fund ( holotype, specimen number IVPP V2885.1 -7 ) consists of a well-preserved skull, parts of the facial skeleton ( prefrontal ( frontal ), parietal ( parietal ) and nose ( nasal ) ), an upper jaw, the second cervical vertebra (axis ) and six caudal vertebrae. These bones probably belonged to a single individual. The finding comes from the Ulansuhai lineup. Other dinosaur remains from this formation include the Neovenatoriden Chilantaisaurus, the Ornithomimosaurier Sinornithomimus, the Ankylar Gobisaurus and a Iguanodontiden with a.
The genus was described in 2009 by Shaochilong Brusatte and colleagues first scientifically. The name comes from Chinese and means something like " Haizahndrache " ( shaochi - " shark tooth " long - "Dragon ").