Dicraeosaurus
| Dicraeosaurus | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Live reconstruction of Dicraeosaurus hansemanni |
||||||||||||
| Temporal occurrence | ||||||||||||
| Upper Jurassic ( Tithonian ) | ||||||||||||
| 152.1 to 145 million years | ||||||||||||
| Locations | ||||||||||||
|
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Dicraeosaurus | ||||||||||||
| Janensch , 1914 | ||||||||||||
| species | ||||||||||||
|
Dicraeosaurus is a genus of sauropod dinosaur from the Upper Jurassic ( Tithonium ) of Tanzania (East Africa). Described was Dicraeosaurus by the German dinosaur researcher Werner Janensch .
description
Dicraeosaurus is a rather small sauropod (by sauropod standards) of about 13 m in length. Like all sauropods, the animal moved on all four legs ( Quadrupedie ) and had a small skull, long neck, massive body and long tail. However, the neck of Dicraeosaurus is rather short compared to other sauropods. The skull resembled that of Diplodocus , so it was elongated, with nostrils lying high on the head and teeth limited to the front end of the muzzle. Most of the distinctive features of Dicraeosaurus are found in the spine . In the neck and vertebrae, the spinous processes are very high and forked, and unlike most other sauropods, they are inclined forward in the neck. The name of the genus, which can be translated as "forked lizard", also refers to the Y-shaped spinous processes of the cervical vertebrae. Large cavities in the sides of the vertebral bodies , so-called pleurocoels, as they are typical for sauropods, are almost completely absent. The tail is about as long as the rest of the body and ends in a slender, whip-like point. The legs are strong and columnar and Dicraeosaurus , like all dinosaurs, was a toe walker .
Systematics
Two species of Dicraeosaurus are known, D. hansemanni and D. sattleri . Dicraeosaurus is the eponymous genus of the Dicraeosauridae family . The Dicraeosauridae are divided into three groups within the Diplodocoidea, which in turn belong to the Neosauropoda . Currently (as of 2019) there are seven dicraeosaurid species from the Central Jurassic of China ( Lingwulong shenqui ), the Upper Jurassic of Africa ( Dicraeosaurus ), North America ( Suuwassea emiliae ) and Central Patagonia ( Brachytrachelopan mesai ) as well as the Lower Cretaceous from North Patuspinuspinuspinuspinus , Bajadezaurus and Amargasaurus cazaui ). In contrast to their sister group , the Diplodocidae , the dicraeosaurids are, according to the current state of knowledge, entirely limited to the southern hemisphere ( Gondwana ).
Site and ecology
Dicraeosaurus comes from the famous Tendaguru site in Tanzania and was found during the German Tendaguru expeditions from 1909 to 1913. In Tendaguru three different layers can be distinguished in which dinosaurs occur and which are slightly different ages, the lower, middle and upper dinosaur marl . The two species of Dicraeosaurus therefore did not live together, but occurred in different layers, Dicraeosaurus hansemanni in the lower and middle (Oxfordium and Kimmeridgium) and Dicraeosaurus sattleri in the upper dinosaur marl (Tithonium). The location at Tendaguru represents a tidal zone on the coast and therefore probably not the actual habitat of Dicraeosaurus , which is more likely to be found in the hinterland.
Like all sauropods, Dicraeosaurus was a herbivore . Along with Dicraeosaurus , other types of sauropods have been found, including Brachiosaurus , Tornieria and, in the upper dinosaur marl, Janenschia . Other herbivores in the Tendaguru ecosystem were the ornithopod Dysalotosaurus and the stegosaur Kentrosaurus (also called Kentrurosaurus ). Thus, the various herbivores had to specialize, and Dicraeosaurus and the Dicraeosaurids as a whole seem to have specialized in grazing low vegetation.
literature
- Martin Aberhan, Robert Bussert, Wolf-Dieter Heinrich, Eckhart cabinet, Stephan Schultka, Benjamin Sames, Jürgen Kriwet, Saidi Kapilima: Palaeoecology and depositional environments of the Tendaguru Beds (Late Jurassic to Early Cretaceous, Tanzania). In: Messages from the Museum of Natural History in Berlin. Earth science series. Vol. 5, No. 1, 2002, ISSN 1435-1943 , pp. 19-44, doi : 10.1002 / mmng.20020050103 .
- Werner Janensch : Overview of the vertebrate fauna of the Tendaguru layers, together with a brief characterization of the newly listed sauropod species. In: Archives for Biontology. Vol. 3, 1914, ZDB -ID 500155-9 , pp. 81-110.
- Werner Janensch: The spine of the genus Dicraeosaurus. In: Scientific results of the Tendaguru expedition 1909–1912. NF Series 1, Part 2, Lfg. 1 = Palaeontographica. Supplement. 7, 1, 2, 1, 1929, ISSN 0085-4611 , pp. 1-34.
- Werner Janensch: An erected skeleton of Dicraeosaurus hansemanni. In: Scientific results of the Tendaguru expedition 1909–1912. NF Series 1, Part 2, Lfg. 3 = Palaeontographica. Supplement. 7, 1, 2, 3, 1935, pp. 301-308.
- Werner Janensch: The skulls of the sauropods Brachiosaurus, Barosaurus and Dicraeosaurus from the Tendaguru layers of German East Africa. In: Scientific results of the Tendaguru expedition 1909–1912. NF series 1, part 2, series 2-3 = Palaeontographica. Supplement. 7, 1, 2, 2-3, 1935-1936, pp. 147-298.
- Werner Janensch: The limb masks and limb belts of the sauropods of the Tendaguru layers. In: Scientific results of the Tendaguru expedition 1909–1912. NF Series 1, Part 3, Lfg. 4 = Palaeontographica. Supplement. 7, 1, 3, 4, 1935-1936, pp. 177-235.
- Paul Upchurch , Paul M. Barrett : The evolution of sauropod feeding mechanisms. In: Hans-Dieter Sues (Ed.): Evolution of herbivory in terrestrial vertebrates. Perspectives from the fossil record. Cambridge University Press, Cambridge et al. 2000, ISBN 0-521-59449-9 , pp. 79-122.
Web links
Individual evidence
- ^ Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ et al. 2010, ISBN 978-0-691-13720-9 , pp. 187-188, online .
- ↑ Phylogenetic position of the Dicraeosauridae. In: nature.com. July 13, 2018, accessed February 22, 2019 .