Probactrosaurus

Probactrosaurus
Skeletal reconstruction of Probactrosaurus in the Chinese Paleozoological Museum
Temporal occurrence
Lower Cretaceous ( Albium )
112.9 to 100.5 million years
Locations
Dashuigou Formation ( Inner Mongolia , China )
Systematics
Pelvic dinosaur (Ornithischia) Cerapoda Ornithopoda Iguanodontia Hadrosauroidea Probactrosaurus
Scientific name
Probactrosaurus
Rozhdestvensky , 1966
Art
Probactrosaurus gobiensis

Skull of Probactrosaurus in the Chinese Paleozoological Museum

Probactrosaurus is an extinct genus of Iguanodontia from the group of ornithopods . Fossils were found in Inner Mongolia in China and aredatedto the Lower Cretaceous ( Albian ). They weredescribedas Probactrosaurus by Anatoly Konstantinovich Rozhdestvensky in 1966. The only species is Probactrosaurus gobiensis .

features

Live reconstruction

Probactrosaurus was a herbivorous dinosaur. Gregory Paul estimated a length of 5.5 meters and a weight of one ton. Probactrosaurus was a slightly built ornithopod with comparatively long and slender limbs. The thumb thorn that is typical of the Iguanodontia was small. It had a narrow snout, an elongated lower jaw and dental batteries including a replacement row of teeth.

History of discovery and research

During a Chinese expedition in Inner Mongolia in 1959 and 1960, the fossils of an ornithopod were found and described by Anatoly Konstantinovich Rozhdestvensky in 1966 . Rozhdestvensky put forward the theory that Probactrosaurus was a direct ancestor of the hadrosaur Bactrosaurus , a thesis disproved today. The generic name means something like 'pre- Bactrosaurus '; the species name refers to the Gobi desert . The holotype PIN 2232/1 consists of a skull and the postcranial skeleton. He was found in the Dashuigou formation . In addition to the holotype, there is another example, PIN 2232-10, which consists of a partial skeleton. In 1966 Rozhdestvensky named a second species in addition to Probactrosaurus gobiensis , Probactrosaurus alashanicus ; this was based on fragments. In 2002, David Bruce Norman concluded that the two species are identical.

In 1997 Lü Junchang described a third species, Probactrosaurus mazongshanensis . It was later found that this species is more closely related to Altirhinus and Equijubus than to Probactrosaurus gobiensis .

Systematics

Probactrosaurus is considered a representative of the Hadrosauroidea within the Iguanodontia . However, the relationships are unclear. The closest relatives are Equijubus and Protohadros . A study by Prieto-Marquez and Norell (2010) found that Probactrosaurus is a basal Hadrosauroidea. A sister taxon is a clade that contains, on the one hand, a nameless group with Protohadros and Eolambia and another nameless clade, which includes the hadrosaurs . The following is a cladogram according to Prieto-Marquez and Norell (2010):

Hadrosauroidea	Jinzhousaurus      Penelopognathus     Equijubus      Probactrosaurus      Eolambia      Protohadros      Tanius     Bactrosaurus      Gilmoreosaurus      Telmatosaurus      Shuangmiaosaurus      Nanyangosaurus      Lophorhothon      Hadrosauridae

Individual evidence

1. ^ ^{A b} Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ et al. 2010, p. 292, ISBN 978-0-691-13720-9 , online .
2. ^ Douglas Palmer: The Marshall illustrated Encyclopedia of Dinosaurs and prehistoric Animals. A comprehensive, color guide to over 500 species. London Marshall 1999, ISBN 1-84028-152-9 , p. 145.
3. ↑ Анатолий К. Рождественский: Новые игуанодонты из Центральной Азии. Филогенетические и таксономические взаимоотношения поздних Iguanodontidae и ранних Hagrosauridae. In: Палеонтологический Журнал. No. 3, 1966, ISSN  0031-031X , pp. 103-116.
4. ^ David B. Norman : On Asian ornithopods (Dinosauria: Ornithischia). 4. Probactrosaurus Rozhdestvensky, 1966. In: Zoological Journal of the Linnean Society. Vol. 136, No. 1, 2002, ISSN  0024-4082 , pp. 113-144, doi : 10.1046 / j.1096-3642.2002.00027.x .
5. ↑ Junchang Lü: A new Iguanodontidae (Probactrosaurus mazongshanensis sp. Nov.) From Mazongshan area, Gansu Province, China. In: Zhiming Dong (ed.): Sino-Japanese Silk Road Dinosaur Expedition. China Ocean Press, Beijing 1997, ISBN 7-5027-4298-0 , pp. 27-47.
6. ↑ Albert Prieto-Marquez, Mark A. Norell : Anatomy and Relationships of Gilmoreosaurus mongoliensis (Dinosauria: Hadrosauroidea) from the Late Cretaceous of Central Asia (= American Museum Novitates. No. 3694, ISSN  0003-0082 ). American Museum of Natural History, New York NY 2010, online .