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'''Yunnanosaurus''' is a genus of prosauropod dinosaur from the Early to Middle Jurassic Period; a position in time that makes it one of the last prosauropods. It is closely related to ''Lufengosaurus''. Known from two valid species, ''Yunnanosaurus'' ranged in size from 7 meters (23 feet) long and 2 m (7 ft) high to 13 m (42 ft) long in the largest species. It is known from over twenty skeletons, including two skulls, recovered from the Lufeng Formation of Yunnan, China.

Contents

Dentition

Classification

References

External links

Dentition

''Yunnanosaurus'' was unique among prosauropods in that its teeth were self-sharpening. There were more than sixty of these spoon shaped teeth in the jaws of ''Yunnanosaurus''. Scientists consider these teeth to be advanced compared to other prosauropods. They share features with the sauropods. However, scientists do not consider ''Yunannosaurus'' to be especially close to the sauropods in phylogeny because the remaining portions of the animals body are distinctly prosauropod in design. The similarity in dentition between ''Yunnanosaurus'' and sauropods might be an example of Convergent Evolution.

Classification

The type species, ''Y. huangi'', was named by C. C. Young in 1942, and he erected the family Yunnanosauridae to contain it, though the family currently comprises only this genus.^[1] Young also named a second species, ''Y. robustus'', in 1951,^[2] but this has since been included in the type species. The confusion in classification arose due to that the earliest specimens were of juveniles while the "Y. robustus" specimens represented fully grown adults. In 2007, Lu and collegues described another species of ''Yunnanosaurus'', ''Y. youngi'' (named in honor of C. C. Young). In addition to various skeletal differences, at 13 meters (42 ft) long ''Y. youngi'' was significantly larger than ''Y. huangi'' (which reached only 7 meters), and ''Y. youngi'' is found later in the fossil record, hailing from the Middle Jurassic.^[3]

References

1. Young, C. C. (1942). "''Yunnanosaurus huangi'' Young (gen. et sp. nov.), a new Prosauropoda from the red beds at Lufeng, Yunnan." ''Bulletin of the Geological Society of China'', '22' (1-2): 63-104.
2. Young, C. C. (1951). "The Lufeng saurischian fauna in China."
''Paleontologica Sinica'', ser. C, '13': 1-96.
3. Lu, J., Li, T., Zhong, S., Azuma, Y., Fujita, M., Dong, Z., and Ji, Q. (2007). "New yunnanosaurid dinosaur (Dinosauria, Prosauropoda) from the Middle Jurassic Zhanghe Formation of Yuanmou, Yunnan Province of China." ''Memoir of the Fukui Prefectural Dinosaur Museum'', '6': 1-15.

External links

★ DinoRuss