Tazoudasaurus
Representative cervical, dorsal, and caudal vertebrae of Tazoudasaurus.
- Ouarzazate, Morocco ( Toundoute - continental series)
- Tazoudasaurus naimi
Tazoudasaurus is a genus of sauropod dinosaur whose remains were discovered in the High Atlas of Morocco and the Lower Jurassic ( Toarcian ) be dated.
Tazoudasaurus is one of the most primitive known sauropods, its skeleton shows a mosaic of advanced features, which are typical for sauropods, and original features, as found in the precursors of sauropods ( original Sauropodomorpha or " prosauropods "). Tazoudasaurus is the most recorded very original sauropod and thus for understanding the early evolution of this group of great importance. The only way is Tazoudasaurus naimi.
Tazoudasaurus is after one of the localities, Tazouda, named, while the Artepitheth naimi comes from the Arabic language and means as much as " slim " - so it should be pointed to the comparatively small body size of the animal.
Features
Like all sauropods, it was a herbivore with a long neck and tail. Unlike the two-legged sauropod precursor of Tazoudasaurus was already like all sauropods obligate quadrupedal. Tazoudasaurus was a relatively small sauropod. Adult animals reached a length of 9.5 and 10 meters and a weight of approximately 8 tons, one of the juveniles found, however, is reconstructed to a weight of 140 kilograms. The skull is reconstructed to a length of 32 centimeters.
The skeleton shows both typical Sauropodenmerkmale and original features which were the precursors for the sauropods ( original Sauropodomorpha ) characteristic, was lost at advanced sauropods, however. Thus, the lower jaw on either side were filled with 18 D- shaped teeth which are not overlapped with each other. The teeth were straight and ran it in plan view a V-shape toward each other, the muzzle was only slightly rounded. In contrast, advanced sauropods had shorter tooth rows with fewer teeth, but which mutually overlapped; also ran the rows of teeth when viewed from above a U-shape, and not a V-shape as in Tazoudasaurus. Wear and tear caused by the direct contact with the teeth of the upper jaw can be, involved an oral processing of food before swallowing.
In the early evolution of sauropods a far-reaching restructuring of the hand skeleton took place. The original plan was characterized by splayed hand beams with fully trained finger bones from; in advanced sauropods fingers were against greatly reduced, and the rays of the metacarpal were not spread apart, but were closely related and formed a semicircle. Tazoudasaurus is the first discovered original sauropod, which is known to a complete skeleton of the hand, and clarifies the long disputed question of when the specialized hand skeleton of the more advanced sauropods has developed. Tazoudasaurus showed only three phalanges in the second finger and two on the third finger - less than original Sauropodomorpha. However, the skeleton of the hand followed the spread, the original plan, the hypothesis confirmed that the specialized blueprint of advanced sauropods first appeared in the original representatives of Neosauropoda. The foot of Tazoudasaurus also showed original features, the foot bones were still relatively long.
Discoveries and research history
The Tazoudasaurus fossils were discovered as part of the 1999 launched " Dino Atlas Project" by an international team of researchers near the village Toundoute in the Moroccan province of Ouarzazate. By 2010, the remains were recovered from at least 10 copies, which is known to the majority of the skeleton today. However, there are missing parts of the spine and the majority of the facial skeleton. The finds belong to adult animals and pups and come from six closely spaced sites. One of these sites contained, besides the Tazoudasaurus fossils the remains of the dinosaur Cerato Berberosaurus. The majority of the fossils is now archived in the collection of the Musée des Sciences de la Terre in Rabat.
In 2004 Tazoudasaurus of researchers led by Ronan Allain was first scientifically described. The description was based on two fragmentary skeletons that were found partially in the anatomical skeleton composite: The holotype specimen includes both skull and bones of a partial skeleton of an adult animal, as well as the skeleton of a young animal. 2008 was followed by an extensive anatomical description in light of other, newly discovered specimens. In a third, published in 2010, publishing a reconstruction of the skeleton has been published.
Morocco is relatively rich in the remains of earlier sauropods, which are very rare worldwide. Thus, the sauropods " Cetiosaurus " mogrebiensis and Atlasaurus imelakei were found in the mountains of the High Atlas also. From North America are similar to old sauropod unknown; since the separation of Africa and America, but only started in the Middle Jurassic, the same fauna was probably native to North America.
Tazoudasaurus
Neosauropoda
System
The closest known relative of Tazoudasaurus is the contemporary Vulcanodon, both genera differ only in characteristics to the vertebrae. Tazoudasaurus shows a number of features that were previously known only from Vulcanodon. To substantiate the similarity with Vulcanodon and to create a differentiation from other primitive sauropods like Barapasaurus, presented the describer Tazoudasaurus together with Vulcanodon in the family Vulcanodontidae which forms the sister group of the Eusauropoda. The Vulcanodontidae ( Cooper, 1984), originally involved the types Vulcanodon and Barapasaurus and later more basal sauropods, but is no longer recognized with this definition by most researchers because Barapasaurus is now classified as Eusauropode - so that would be the Vulcanodontidae paraphyletic. The describer of Tazoudasaurus defined the Vulcanodontidae new as a group, which includes all species that are more closely related than Vulcanodon with Eusauropoden; this definition includes Barapasaurus out of this group. The new definition has not been widely accepted; in recent analyzes (eg Wilson, 2005), the Vulcanodontidae is usually not used.
Taphonomy and behavior
The Tazoudasaurus fossils come from two very bone- rich layers - so-called bonebeds - which are stratigraphically separated by a 30 meter thick sedimentary sequence. Both bonebeds are interpreted as debris flows, and are therefore deposited by flowing downhill mud flows within the shortest possible time. Most specimens are from the upper bonebed while from the lower far only two specimens were recovered. The researchers suggest that at least the animals of the upper bonebeds been buried by the debris flows and are killed. If this interpretation is correct, that would be an indication of a life in groups, which consisted of both adult and very young animals. Together with the two copies of the lower - Tazoudasaurus bonebeds the remains of the Cerato Berberosaurus dinosaur were found, which has the sauropods may be hunted.