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09.01.2016 00:35 - Largest prehistoric animals Vol.1 Vertebrates part3 Dinosaurs ch.3 Ornithischia - Ornithopods,the largest walking on two legs animals
Автор: valentint Категория: Забавление   
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Последна промяна: 05.12.2016 21:26


Ornithopods (Ornithopoda)

Shantungosaurus giganteus



The very largest ornithopods, like Shantungosaurus were as heavy as medium sized sauropods at up to 23 metric tons. (25 short tons)The largest is probably Shantungosaurus at 16.5 metres (54 ft) in length.

Shantungosaurus giganteus is one of the largest known ornithischians, the type skull is 1.63 metres (5.3 ft) long  and the composite skeleton mounted at the Geological Institute of China in Beijing measures 14.72 metres (48.3 ft) in length while another mounted skeleton, originally referred to "Zhuchengosaurus maximus", measures 16.6 metres (54 ft) in length.The largest individuals may have weighted as much as 16 tonnes (18 short tons). Like all hadrosaurs its beak was toothless, but its jaws were packed with around 1,500 tiny chewing teeth. A large hole near its nostrils may have been covered by a loose flap, which could be inflated to make sounds.

First described in 1973, Shantungosaurus is known from over five incomplete skeletons. Chinese scientist Xing Xu and his colleagues indicate that Shantungosaurus is very similar to and shares many unique characters with Edmontosaurus, forming an Asian node of Edmontosaurus–Shantungosaurus clade, based on the new materials recovered in Shandong. Remains of several individuals, including skull bones, limb bones, and vertebrae, were found in Shandong, China. These specimens were classified in the new genus and species Zhuchengosaurus maximus in 2007.However, further study showed that the supposedly distinct features of Zhuchengosaurus were simply a result of different growth stages.

Recent maximum parsimony analyses of Hadrosauroidea recovered a stable sister group relationship between Edmontosaurus and Shantungosaurus. Shantungosaurus is the single hadrosaurid from the Zhucheng area that is considered valid. Zhuchengosaurus and Huaxiaosaurus, both of which are known from the same region, are interpreted here as junior synonyms of Shantungosaurus. All unequivocal morphological discrepancies among these three taxa could be attributed to intraspecific variation (ontogenetic and polymorphic variation) and post-depositional distortion.


Huaxiaosaurus

Huaxiaosaurus
is a genus of saurolophine hadrosaurid dinosaur, discovered in Cretaceous rocks of Zhucheng, Shandong, China. A large hadrosaur, some of its estimated dimensions include a length of 18.7 metres (61 ft) and a height of 11.3 metres (37 ft) (in a tripodal posture) makes it one of the largest Ornithopods known. It lived in the same time and place as Shantungosaurus and Zhuchengosaurus and is almost certainly the same animal as Shantungosaurus.

In March 2008 during excavations in the quarry near the city of Zhucheng, the province of Shandong, bones were found belonging to the prehistoric species. In addition to the fossils of many different species, the skeleton of a huge hadrosaur was found. The excavation uncovered a block the size of twenty square metres containing this giant beast. After a careful examination it was concluded that the bones belonged to a giant new species of dinosaur, different from others like Shantungosaurus and Zhuchengosaurus.n 2011 came the scientific description, sponsored by Wang Kebai and Li Dunjing. A new species of dinosaur had been named. The genus name is derived from Huaxia - the ancient word for China. The specific epithet is given in Chinese, (jù dà), and means giant. Aigahtens is identical to the Latin word giganteus. Huaxiaosaurus should not be confused with Huaxiasaurus, a nomen nudum, and the later name for it, Huaxiagnathus.

The type and only specimen consists of a fairly complete skeleton with a skull. The bones were found in the geological strata, of the Xingzhuang Formation. It includes the left thigh, the middle part of the lower jaw, a large part of the spine, the shoulders, the front legs, the pelvis and the hind legs. Huaxiaosaurus differs from Zhuchengosaurus by owning ten, instead of nine, sacral vertebra and Shantungosaurus by a groove in the underside of the sacral vertebrae. Other researchers, however, had already stated that the quarry, which Zhuchengosaurus also shows, was not sufficient to distinguish. In the older kind of Shantungosaurus the coalescence of extra vertebrae in the sacrum was a common effect of aging. It may be that all three taxa coincide in the name Shantungosaurus, and that Huaxiaosaurus just represents a big old individual of that species.The skull is very elongated, narrow and flat. The lower jaws are high. The teeth are in high tooth batteries. The spine consists of 16 cervical vertebra, 20 dorsal vertebra, 10 sacral vertebra and 18 (preserved) tail vertebra. The cervical vertebrae are relatively short and spinous; however there are long spines on the vertebra near the base of the tail. The front legs are relatively small with four weight bearing fingers but in absolute terms still reach a length of 2 metres (6 ft 7 in). The humerus, 92–98 centimetres (36–39 in) long, was quite robust in order to support the massive weight of this hadrosaur. The hind legs are very robust and heavily muscled. The femur is 170–172 centimetres (67–68 in) long. The tibia is shorter at 145–147 centimetres (57–58 in) long.Estimate for this animal is a length of 18.7 metres (61 ft), and a height of 11.3 metres (37 ft) (in a tripodal posture).



Magnapaulia



Magnapaulia is a genus of herbivorous lambeosaurine dinosaur known from the Latest Cretaceous Baja California, of northwestern Mexico. It contains a single species, Magnapaulia laticaudus.Magnapaulia was first described in 1981 as a possible species of Lambeosaurus by William J. Morris,and was given its own genus in 2012 by Prieto-Márquez and colleagues.

 

Between 1968 and 1974, a team of the Natural History Museum of Los Angeles County headed by geologist William J. Morris excavated giant lambeosaurine remains from a site near El Rosario in Baja California. Morris named them ?Lambeosaurus laticaudus in 1981, based on type specimen LACM 17715, a partial skeleton with partial skull. Morris added a question mark to the front of the generic name to indicate its provisional nature: because no complete crest had been found for his species, and without it a definitive assignment could not be made. From what was known of the skull, he considered it to be most like Lambeosaurus. The specific name is derived from the Latin latus, "broad", and cauda, "tail". Morris interpreted this species as water-bound, due to features like its size, its tall and narrow tail (interpreted as a swimming adaptation), and weak hip articulations, as well as a healed broken thigh bone that he thought would have been too much of a handicap for a terrestrial animal to have survived long enough to heal.Between 1981 and 2012, other authors accepted it as a potential species of Lambeosaurus,suggested it could instead be a species of Hypacrosaurus,or questioned its validity.

In 2012 it was named as a separate genus by Albert Prieto-Márquez, Luis Chiappe, and Shantanu Joshi. The generic name is a combination of the Latin magnus, "large", and the first name of Paul G. Haaga, Jr., the president of the board of trustees of the Los Angeles County Museum of Natural History. The 2012 study indicated that the remains had been found in a layer of the El Gallo Formation, dating to the late Campanian, about 73.6 to 73 millions years old. The study referred numerous other specimens to the species: LACM 17698, 17699, 17700, 17702-17713, 17716 and 17717; LACM 20873-20876; and LACM 20883-20885. These had been found within a distance of three metres to the holotype and consist of partial skeletons, separate bones and skin impressions from several individuals, varying in size. In 2012 a complete redescription of the body parts was given.

Magnapaulia is noted for its great size and the tall profile of its tail, which had elongated chevrons and vertebral spines like those of Hypacrosaurus.Its size was estimated by its original describer as between 15 m (49.2 ft) and 16.5 m (54.1 ft) long, with a weight of up to 23 metric tons (25 tons);Prieto-Márquez et al. provided a smaller estimate of around 12.5 metres (41 ft), still among the longest ornithischians and representing the largest known lambeosaurine. The largest known specimen is LACM 17712, which includes a humerus with an estimated original length of 803 millimetres.

The redescription of 2012 established two autapomorphies, unique derived traits: the presence of chevrons at the tail base that were four times as long as the vertebral centra; and the possession at the tail base vertebrae of front joint processes, prezygapophyses, the inner bases of which formed a bowl-shaped depression that extended upwards into a deep trough on the front surface of the spine.

On the vertebral column, from at least the middle of the back to over the middle of the tail, a tall crest of almost continuous height was present formed by spines that were about four times as high as the vertebral centra.

Magnapaulia is among the many hadrosaurids that have preserved skin impressions; the tail of specimen LACM 17712 had some up to four centimetres wide scales, or perhaps bony osteoderms, embedded within up to one centimetre long hexagonal and smaller rounded scales.

In 2012 Magnapaulia was assigned to the Lambeosaurinae. The 2012 study contained a cladistic analysis which found it to be closest to Velafrons, also from Mexico, with this sister species forming a separate southern clade, itself the sister group of a clade of more northern Asian and North-American forms, including Lambeosaurus, Corythosaurus, Hypacrosaurus and Olorotitan.













Тагове:   сова,   prehistoric animals,   giant animals,   dinosaurs,


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