Brachiosauridae
| Brachiosauridae | ||||||||||||
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Giraffatitan ( Syn. Brachiosaurus brancai ) in the Berlin Natural History Museum. |
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| Temporal occurrence | ||||||||||||
| Upper Jurassic to Lower Cretaceous ( Kimmeridgian to Middle Albian ) | ||||||||||||
| 157.3 to 107.5 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Brachiosauridae | ||||||||||||
| Riggs , 1904 |
The Brachiosauridae were a group of sauropod dinosaurs . They lived from the Upper Jurassic to the Lower Cretaceous . Their fossils were found mainly in North America, Africa and Europe.
In contrast to other sauropods, this group is characterized by unusually long front legs that were the same length or even longer than the rear legs. This blueprint resulted in a giraffe-like appearance. The taxon Brachiosauridae was established by Elmer Riggs as early as 1904 - this group is one of the first described sauropod groups. The Brachiosauridae is considered an original group of the Macronaria ; other representatives of the Macronaria were for example Camarasaurus , Euhelopus and the Titanosauria . Today the brachiosaurids are among the best scientifically examined sauropods.
features
General
The Brachiosauridae shows a physique that is typical of the original Macronaria: the limbs are relatively slim and long in relation to the trunk, which led to an increased step width. The forelegs were longer in relation to the hind legs than in other sauropods - although this feature is most pronounced in the brachiosaurids, it is also evident in Euhelopus . While the forelegs were long, the pelvic girdle was reduced in size: this indicates that the main drive for locomotion came from the forelegs, rather than the hind legs, as with other sauropods. The hind legs were not exactly perpendicular under the body, but were slightly spread outwards - this feature was much more pronounced in the more advanced Titanosauria .
size
The largest relatively complete skeletons are the type specimens of Brachiosaurus altithorax and Giraffatitan brancai (formerly Brachiosaurus brancai ); both skeletons show only minor differences in size. Taylor (2009) estimates the weight of the Brachiosaurus specimen at 28.7 tons and that of the Giraffatitan specimen at 23.3 tons, while Paul (1988) estimates 35 tons for the Brachiosaurus specimen and 31.5 tons for the Giraffatitan specimen indicates. These differences in weight between the two skeletons can be traced back to different body proportions: Brachiosaurus had a longer body and a longer and thicker tail than Giraffatitan .
Other findings indicate that brachiosaurids could become significantly larger. A fibula belonging to Giraffatitan is 13% larger than the corresponding bone in the type specimen. The type specimen of Brachiosaurus probably belonged to a not yet adult individual, which indicates that this genus could also become significantly larger. The largest brachiosaurid could have been Sauroposeidon , which is only known for a series of four very long cervical vertebrae. Assuming that this genus showed the same physique as Brachiosaurus , Sauroposeidon would have had a length of 28 meters and a weight of up to 50 tons. The shoulder height of this genus would have been 6 to 7 meters; the 11 to 12 meter long neck could have reached heights of up to 18 meters.
Age
Finds so far come from the Upper Jurassic and Lower Cretaceous ( Kimmeridgian to Middle Albian ). However, caudal vertebrae discovered in Mexico indicate that this group still existed during the Upper Cretaceous in the late Campanian .
Systematics
The Brachiosauridae were original Macronaria . Most authors, such as Upurch and colleagues (2004), represent the Barchisauridae as the sister taxon of the Titanosauria . These are combined to form the Titanosauriformes . Together with the Camarasauridae they form the Macronaria. Wilson (2002) summarizes the genus Euhelopus and the Titanosauria to Somphospondyli and considers this taxon as a sister taxon of the Brachiosauridae.
The following cladogram illustrates the theory of Upurch and colleagues (2004):
| Macronaria |
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literature
- Elmer S. Riggs : Structure and relationships of opisthocoelian dinosaurs, part II: The Brachiosauridae. In: Field Columbian Museum. Publication. Geological Series. Vol. 2, No. 6, 1904, ISSN 0097-3637 , pp. 229-247.
Individual evidence
- ^ A b Gregory S. Paul : The Princeton Field Guide To Dinosaurs. 2010, ISBN 978-0-691-13720-9 , p. 124, online ( Memento of the original from 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. .
- ↑ TaxonSearch ( Memento of the original from January 27, 2008 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. Last accessed: December 29, 2007
- ^ A b Hai-Lu You, Da-Qing Li: The first well-preserved Early Cretaceous brachiosaurid dinosaur in Asia. In: Proceedings of the Royal Society. Series B: Biological Sciences. Vol. 276, No. 1675, 2009, ISSN 0080-4649 , pp. 4077-4082, doi : 10.1098 / rspb.2009.1278 .
- ^ Matthew T. Carrano: The Evolution of Sauropod Locomotion: morphological diversity of a secondarily quadrupedal radiation. In: Kristina Curry A. Rogers, Jeffrey A. Wilson: The Sauropods. Evolution and Paleobiology. University of California Press, Berkeley, Cal. et al. 2005, ISBN 0-520-24623-3 , pp. 229-251.
- ^ A b c Michael P. Taylor: A Re-Evaluation of Brachiosaurus altithorax Riggs 1903 (Dinosauria, Sauropoda) and Its Generic Separation from Giraffatitan brancai (Janensch 1914). In: Journal of Vertebrate Paleontology. Vol. 29, No. 3, 2009, ISSN 0272-4634 , pp. 787-806, doi : 10.1671 / 039.029.0309 .
- ^ Mathew J. Wedel, Richard L. Cifelli: Sauroposeidon: Oklahoma's Native Giant. In: Oklahoma Geology Notes. Vol. 65, No. 2, 2005, ISSN 0030-1736 , pp. 40-57, digital version (PDF; 2.15 MB) .
- ↑ James I. Kirkland , Martha C. Aguillon Martinez, Rivera Hernandez Rivera, Virginia A. Tidwell: A late Campanian brachiosaurid proximal caudal vertebra from Coahuila, Mexico: evidence against a Cretaceous North American sauropod hiatus. In: Journal of Vertebrate Paleontology. Vol. 20, Supplement to No. 3 = Abstracts of Papers, Sixtieth Annual Meeting Society of Vertebrate Paleontology, Fiesta Americana Reforma Hotel, Mexico City, Mexico, October 25-28, 2000 , 2000, pp. 51A-52A.
- ^ A b Paul Upchurch , Paul M. Barrett , Peter Dodson : Sauropoda. 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. 259-324.
- ↑ Jeffrey A. Wilson: Sauropod dinosaur phylogeny: critique and cladistic analysis. In: Zoological Journal of the Linnean Society. Vol. 136, No. 2, 2002, ISSN 0024-4082 , pp. 215-275, doi : 10.1046 / j.1096-3642.2002.00029.x .
