Dicreosaurus [1] ( Latin Dicraeosaurus ) is a genus of herbivorous dinosaurs from the Upper Jurassic era, representatives of the infraorder Zauropod . Close relatives of diplodok , belong to the family of dicreosaurus [1] ( Dicraeosauridae ) of the diplodocoid family. Small zauropody, up to 13 meters long, weighing up to 3-4 tons.
| † Dicreosaurus |
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| Scientific classification |
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| No rank : | Bilateral symmetric |
| Infraclass : | Archosauromorphs |
| No rank : | Archosauriformes |
| Suborder : | † Zavropodomorfy |
| Infrastructure : | † Zauropods |
| Superfamily : | † Diplodocoidea |
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| International Scientific Name |
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Dicraeosaurus Janensch, 1914 |
| Kinds |
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- † Dicraeosaurus hansemanni
Janensch, 1914 typus - † Dicraeosaurus sattleri
Janensch, 1914
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Geochronology155.7-145.5 Ma | million years | Period | Era | Eon |
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| 2.588 | Even | | | Ka | F
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th | | 23.03 | Neogene | | 66.0 | Paleogene | | 145.5 | a piece of chalk | M
e
s
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s
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th | | 199.6 | Yura | | 251 | Triassic | | 299 | Permian | P
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th | | 359.2 | Carbon | | 416 | Devonian | | 443.7 | Silur | | 488.3 | Ordovician | | 542 | Cambrian | | 4570 | Precambrian |
◄ Nowadays◄ Cretaceous-Paleogene extinction◄ Triassic extinction◄ Perm mass extinction◄ Devonian extinction◄ Ordovician-Silurian extinction◄ Cambrian explosion |
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Differ in relatively short neck and large head. Very high forked spinous processes are characteristic. The front limbs are small but powerful. One of the most primitive known representatives of the group of diplodok. However, dicreosaurs are characteristic of Upper Jurassic ( Cimmeridge ) sediments - they represent a surviving group of primitive diplodocus. Actually Dicraeosaurus is known only from the Upper Jurassic of Tanzania ( Tendaguru ).
The type species - D. hansemanni , characteristic of the middle layers of Tendaguru, makes up approximately 22% of all the sapropod finds in these sediments. Probably lived in large herds, fed by low vegetation.
The second D. sattleri species is somewhat younger in age, belonging to the upper layers of Tendaguru. This is a very small pot, not more than 1 ton in weight. It has even higher spinous processes in the neck. This species is transitional to another representative of Dikreozavrid - amargazavru ( lower Cretaceous Argentina ). In Amargazaurus ( Amargasaurus cazaui ), the spinous processes on the neck form high forked spikes. Perhaps the spikes maintained a kind of “sail” or served to protect. Amargazavr did not exceed 10-12 meters in length. Other dikreozavridy - brachytrahelopan ( Brachytrachelopan mesai ) from Upper Jurassic ( Tithonian ) sediments of Argentina and Amazonasaurus ( Amazonsaurus marahensis ) from the Lower Cretaceous of Brazil .
Thus, dikreozauridy represent the Gondwan group of diplodocus. Their existence is limited to the upper Jurassic - lower chalk. Previously, this group also included some of the gravestones from the Upper Cretaceous of Mongolia ( nemetosaurus [2] ), but now there is also a point of view according to which they belong to titanosaurs [3] .
