Megaraptoridae
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Reason: The only characteristics to be listed under characteristics are those that all members of the group have in common and that make them distinguishable from other groups, especially the closest related groups, not a synopsis of individual characteristics of the individual subtaxa. Furthermore, the italicization of the names of taxa of the genus and species group was ignored (which is a formality, the fulfillment of which can be saved for a revision ...) --14: 28, Jul. 17, 2018 (CEST)
| Megaraptoridae | ||||||||||||
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Reconstruction of the skull and body of Murusraptor , a representative of the Megaraptoridae from the older Upper Cretaceous Patagonia |
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| Temporal occurrence | ||||||||||||
| Albium to Maastrichtium | ||||||||||||
| 112.9 to 66 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Megaraptoridae | ||||||||||||
The Megaraptoridae are a family of small and medium-sized "higher" predatory dinosaurs from the group of Allosauroidea , which inhabited the southern continents (Australia, South America) during the late Lower and Upper Cretaceous .
features
The characteristics of the Megaraptoridae could vary considerably within the individual genera. Their size was mostly between the medium-sized representatives like Australovenator with five meters and the larger representatives like Aerosteon with up to nine meters. However, it should also be mentioned that many Megaraptoridae are only known through fossil fragments.
They probably had long, flat snouts with very long nostrils and flat nasal bones, which can be recognized, among other things, by the tearbones of Murusraptor or a young Megaraptor . The lower jaw of the Megaraptoridae members was elongated, which can be clearly seen in the lower jaw of Australovenator.
Although the teeth of individual members of the Megaraptoridae were shaped very differently, there are clear similarities in some genera, such as B. Orkoraptor and Megaraptor, which both had teeth with an 8-shaped cross-section, which were imperforate from the front. But there were also some megaraptorids like Murusraptor with anterior serrations only at the tip of the teeth. Australovenator, on the other hand, had extensive spikes on both sides.
Some Megaraptoridae, such as Murusraptor and Aerosteon, had largely pneumatic bones, with the sinuses likely connected to the lungs, as in modern day birds, suggesting persistent runners.
Since the leg bones of the megaraptorids were very slender and they had long metatarsal bones, it seems reasonable to assume that the megaraptorids had likely cursory habits.
The most striking feature of representatives of this group, however, was the oversized first and second fingers of the hand. However, the third finger of the hand was largely smaller than that of other theropods . When the first claw of a Megaraptor was discovered, it was first thought to be the foot claw of a large dromaeosaurid , which gave the genus the name "Megaraptor".
Evolution and expansion
Finds from Australia show that the Megaraptorids had Australian ancestors from the Megaraptora group, which then migrated to the South American part of Gondwanaland and underwent radiation there.
classification
The Megaraptoridae belong to the group of Megaraptora, which belonged either to the Allosauroidea (Benson, Canaron and Brussate 2010) or to the Tyrannosauroidea (Novas et al. 2012). Nowadays many scientists consider the Megaraptora to be representatives of the Allosauroidea.
literature
- Matias Motta, Alexis Aranciaga Rolando, Sebastián Rozadilla, Federico Agnolin, Nicolas Chimento: NEW THEROPOD FAUNA FROM THE UPPER CRETACEOUS (HUINCUL FORMATION) OF NORTHWESTERN PATAGONIA, ARGENTINA . In: New Mexico Museum of Natural History and Science Bulletin . June 16, 2016 ( researchgate.net [accessed July 13, 2018]).
- Sebastián Apesteguía, Nathan D. Smith, Rubén Juárez Valieri, Peter J. Makovicky: An Unusual New Theropod with a Didactyl Manus from the Upper Cretaceous of Patagonia, Argentina . In: PLOS ONE . tape 11 , no. 7 , July 13, 2016, ISSN 1932-6203 , p. e0157793 , doi : 10.1371 / journal.pone.0157793 , PMID 27410683 , PMC 4943716 (free full text) - ( plos.org [accessed July 13, 2018]).
- Porfiri, Juan D., Novas, Fernando E., Calvo, Jorge O., Agnolín, Federico L., Ezcurra, Martín D .: Juvenile specimen of Megaraptor (Dinosauria, Theropoda) sheds light about tyrannosauroid radiation . In: Cretaceous Research . tape 51 , ISSN 0195-6671 ( academia.edu [accessed July 13, 2018]).
- Rodolfo A. Coria, Philip J. Currie: A New Megaraptoran Dinosaur (Dinosauria, Theropoda, Megaraptoridae) from the Late Cretaceous of Patagonia . In: PLOS ONE . tape 11 , no. 7 , July 20, 2016, ISSN 1932-6203 , p. e0157973 , doi : 10.1371 / journal.pone.0157973 , PMID 27439002 , PMC 4954680 (free full text) - ( plos.org [accessed July 13, 2018]).