Dicreosaurus (lat.: Dicraeosaurus) is a genus of herbivorous sauropods from the Dicreosaurid family that lived in the Upper Jurassic period (in the Tithonian stage) on the territory of modern Tanzania (East Africa). It was described by the German paleontologist Werner Janensch (German.: Werner Janensch).
Description
Dicreosaurus was a relatively small representative of sauropods (by the standards of the size standard adopted for them) its body length was “only” about 13 meters.
Like all sauropods, he moved on all four limbs (t.e. was quadrupedal) and had a small skull, long neck, massive body and long tail. True, his neck was rather short compared to other representatives of the infraorder Sauropods (lat.: Sauropoda).
The skull of a dicreosaurus resembles that of a diplodocus (lat.: Diplodocus) it is elongated, has highly located nasal openings, and only the front parts of the jaws are equipped with teeth.
Anatomical features differ mainly in the spine of Dicreosaurus. Its cervical and dorsal vertebrae have forked and very tall spine-like processes, and, unlike most other sauropods, these processes are tilted forward on the cervical vertebrae.
The name of the genus, which can be translated into Russian as “fork lizard” (from the Greek words dicraeos and sauros), is also associated with the Y-shaped form of the spiny processes.
Large lateral cavities in the vertebral bodies, the so-called “pleuroceles”, typical of sauropods, are almost completely absent in Dicreosaurus. The tail is approximately the same length as the rest of the body and ends in a thin, whip-like point. Limbs powerful and columnar.
Classification
Science knows 2 types of this dinosaur:
Dicreosaurus is eponymous (t.e. giving its name to a taxon of a higher rank) is a genus of the Dicreosaurid family (lat.: Dicraeosauridae), which also includes the genus Brachitrachelopan (lat.: Brachytrachelopan) from the Tithonian stage of the Upper Jurassic and Amargasaurus (Amargasaurus) from the Lower Cretaceous, inhabiting the territory of modern Patagonia (South America).
In addition, there is also evidence for the existence of other as yet unclassified dicreosaurids that lived at the beginning of the Upper Cretaceous period (in the Cenomanian stage) in the territories of modern Egypt and Sudan.
In turn, dicreosaurids belong to the superfamily Diplodocoids (lat.: Diplodocoidea) within the Neosauropoda group, which, in addition to diplodocoids, also includes macronares (Macronaria).
Unlike representatives of the sister family Diplodocides (lat.: Diplodocidae), the habitat of dicreosaurids, as is known at the moment, was limited exclusively to the southern hemisphere of the Earth (the ancient supercontinent Gondwana).
Location of discovery and paleoecology
Dicreosaurus fossils were found during the 1909-1913 German paleontological expedition to East Africa in a cluster of dinosaur bones on the famous Tendaguru Hill (Eng.: Tendaguru) in Tanzania.
In the Tendaguru formation, 3 different geological layers can be distinguished, which contain the bones of dinosaurs and differ from each other in age: the lower, middle and upper Jurassic marls. It is assumed that two species of Dicreosaurus did not live simultaneously, since their remains are found in different geological layers: Dicraeosaurus hansemanni in the lower and middle (in the Oxfordian and Kimmeridgian stages), and Dicraeosaurus sattleri in the Upper Jurassic marl (in the Tithonian stage).
The dinosaur cemetery in the Tendaguru Hill area is an intertidal zone of the Indian Ocean, so it is believed that the true habitat of this dinosaur was not located here, but rather somewhere inland.
Food
Like all genera belonging to the infraorder Sauropods, Dicreosaurus was also a herbivorous dinosaur. Together with him, other representatives of the infraorder were found, including the brachiosaurus (lat.: Brachiosaurus), Tornieria (Tornieria) and, in the Upper Jurassic marl, Janenschia (Janenschia).
Other herbivorous dinosaurs in the Tendaguru ecosystem were the ornithopod Disalotosaurus (lat.: Dysalotosaurus) and a representative of the Stegosaurus group (Stegosauria) Kentrosaurus (Kentrosaurus). Apparently, dicreosaurus and dicreosaurids in general specialized in eating stunted vegetation.
