Carcharodontosaurus

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Carcharodontosaurus
Carcharodontosaurus fossil skull

Carcharodontosaurus fossil skull

Temporal occurrence
Upper Cretaceous ( Cenomanium )
100.5 to 93.9 million years
Locations
Systematics
Dinosaur (dinosauria)
Lizard dinosaur (Saurischia)
Theropoda
Allosauroidea
Carcharodontosauridae
Carcharodontosaurus
Scientific name
Carcharodontosaurus
Stromer , 1931
Live reconstruction of Carcharodontosaurus

Carcharodontosaurus (old Greek "sharp-tooth lizard") is a genus of theropod dinosaurs from the early Upper Cretaceous Africa . The genus Carcharodontosaurus is named after the great white shark ( Carcharodon carcharias ).

It was one of the largest known land-dwelling carnivores in the history of the earth . He is the eponymous representative of the Carcharodontosauridae and was closely related to the gigantic genera Giganotosaurus and Mapusaurus . The German paleontologist Ernst Stromer von Reichenbach made the first discoveries of this dinosaur in Algeria and Egypt . However, all of this material was destroyed in the Museum Alte Akademie in 1944 during an Allied air raid on Munich .

A distinction is currently made between two species - the type Carcharodontosaurus saharicus and the Carcharodontosaurus iguidensis, discovered in Niger in 2007 .

Systematics

For a long time it was unclear in which group Carcharodontosaurus should be classified. If Stromer had assigned him to the taxon of the Carcharodontosauridae named after him , this was considered invalid by other scientists and Carcharodontosaurus assigned to the Allosauridae or Tyrannosauridae . In the year 1995 published Oliver WM Rauhut a detailed work to currently accepted classification of Carcharodontosaurus and the related with it bahariasaurus . This publication was mainly based on Stromer's notes , as the original fossils were destroyed in World War II.

Due to many similarities it can be assumed that the Carcharodontosauridae belong to the Allosauroidea ; from other representatives of this group, the Allosauridae and the Sinraptoridae , they probably split off in the Middle Jurassic . They are probably more closely related to the Allosauridae than to the Sinraptoridae. The Carcharodontosauridae were the most strongly derived (most advanced) representatives of the Allosauroidea.

A closer relationship with the Coelurosauria and the Torvosauridae also seems possible, one with the Ceratosauria rather unlikely.

Differentiation between C. saharicus and C. inguidensis

Fossils of a second species, C. inguidensis , have been discovered in Niger . This find shows that teeth and other material from the area around the site that was previously assigned to C. saharicus actually belonged to C. iguidensis . Fossils of Rugops primus and Spinosaurus have also been found nearby, and it is unlikely that more than three large theropods lived together in such a small space. So many fossils from the area have now been assigned to C. iguidensis .

C. iguidensis and C. saharicus differ, among other things, in the structure of the tear bone and the upper jaw . Both species show furrowed teeth, the furrows of C. saharicus being more pronounced than those of C. iguidensis . In addition, C. iguidensis has 15% more brain volume than C. saharicus ; however, both species had less brain mass than Tyrannosaurus .

features

Carcharodontosaurus (purple) compared to the largest known theropod

Carcharodontosaurus was up to 13.7 meters long, had strong claws and teeth that were serrated on both sides, mostly barely curved .

However, regional peculiarities occurred in the various areas of Africa. Characteristic of carcharodontosaurids are, in addition to pleurocoeles (lateral openings) in the caudal vertebrae , which is a rarity among theropods , especially the extremely wide and flat cervical vertebrae .

The frontal bones and cranium of the Carcharodontosaurus show clear differences to those of the Allosauridae and Sinraptoridae and are similar to those of Giganotosaurus and Acrocanthosaurus . An expansion of the middle ear filled with air is also characteristic of Carcharodontosaurus , Acrocanthosaurus and possibly Giganotosaurus .

The anatomy of the inner ear of Carcharodontosaurus is comparable to that of today's crocodiles , the lower jaw has a structure similar to that of other Carcharodontosauridae and the optic nerve and eye movement nerve are very pronounced.

Homo sapiens in size comparison with the reconstructed skull of C. saharicus

brain

In 2000, a research team led by Hans Larsson created skull casts of Tyrannosaurus , Allosaurus and Carcharodontosaurus and compared, among other things, the size ratio of the cerebrum in comparison to the entire brain. As with most dinosaurs , this ratio was also comparable in Carcharodontosaurus and Allosaurus with today's reptiles , while in Tyrannosaurus the cerebrum took up significantly more space. This can be explained by the fact that Tyrannosaurus is much more closely related to the birds than the two Allosauroidea. Compared to their body size, birds have a significantly larger cerebrum than reptiles. In addition, it can be assumed that Tyrannosaurus had a larger total brain volume than Carcharodontosaurus with a similar size .

Discovery and Finds

Tooth compared to a quarter dollar coin

The first fossils belonging to Carcharodontosaurus were two teeth found in Algeria , which were initially incorrectly assigned to Megalosaurus and, like all material found at the time, were lost in World War II.

Later, fossils of this dinosaur were also found in Egypt , Morocco , Tunisia , Libya and Niger .

List of important finds

The Carcharodontosaurus fossils include a skull fragment, the nasal bone , fragments of the left upper jaw , three cervical vertebrae , various teeth , a caudal vertebra , a rib fragment, foot bones, fragments of the left ischium , both pubic bones (destroyed), both femurs (destroyed ) and the left fibula . Stromer also mentions a hip bone in his notes , but its affiliation to Carcharodontosaurus has not been clarified.

Individual evidence

  1. ^ Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ et al. 2010, ISBN 978-0-691-13720-9 , p. 97, online ( memento of the original of July 13, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. . @1@ 2Template: Webachiv / IABot / press.princeton.edu
  2. Stromer, E. (1931). "Vertebrate remains of the Baharije stage (lowest Canoman). A skeletal remains of Carcharodontosaurus nov. Gen." Treatises of the Bavarian Academy of Sciences, Mathematical and Natural Science Department , 9 (new series): 1–23.
  3. ^ Student Identifies Enormous New Dinosaur . In: ScienceDaily , December 17, 2007.
  4. a b c d e f g Oliver Rauhut : The Systematic Position of the African Theropods Carcharodontosaurus Stromer 1931 and Bahariasaurus Stromer 1934. In: Berlin geoscientific treatises. Row E: Paleobiology. Vol. 16, No. 1, 1995, ISSN  0941-7338 , pp. 357-375, online (PDF; 444.98 kB) .
  5. a b c d Donald F. Glut : Dinosaurs. The Encyclopedia. McFarland, Jefferson NC et al. 1997, ISBN 0-89950-917-7 , pp. 253-256.
  6. a b c d e f Stephen L. Brusatte, Paul C. Sereno : A new species of Carcharodontosaurus (Dinosauria: Theropoda) from the Cenomanian of Niger and a revision of the genus. In: Journal of Vertebrate Paleontology. Vol. 27, Vol. 4, 2007, ISSN  0272-4634 , pp. 902-916, doi : 10.1671 / 0272-4634 (2007) 27 [902: ANSOCD] 2.0.CO; 2 .
  7. a b c Hans CE Larsson: Endocranial Anatomy of Carcharodontosaurus saharicus (Theropoda: Allosauroidea) and Its Implications for Theropod Brain Evolution. In: Darren H. Tanke, Kenneth Carpenter (Eds.): Mesozoic vertebrate life. Indiana University Press et al., Bloomington IN et al. 2001, ISBN 0-253-33907-3 , pp. 19-33.
  8. ^ A b Hans CE Larsson, Paul C. Sereno, Jeffrey A. Wilson: Forebrain Enlargement Among Nonavian Theropod Dinosaurs. In: Journal of Vertebrate Paleontology. Vol. 20, No. 3, 2000, pp. 615-618, doi : 10.1671 / 0272-4634 (2000) 020 [0615: FEANTD] 2.0.CO; 2 .
  9. Thomas R. Holtz Jr. , Ralph E. Molnar, Philip J. Currie : Basal Tetanurae. In: David B. Weishampel , Peter Dodson , Halszka Osmólska (eds.): The Dinosauria . 2nd edition. University of California Press, Berkeley CA et al. 2004, ISBN 0-520-24209-2 , pp. 71-110.

Web links

Commons : Carcharodontosaurus  - collection of images, videos and audio files