Dashanpu Formation

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Dashanpu Formation
Stratigraphic range: Mid Bathonian-Late Oxfordian
Type Geological formation
Sub-units Xiashaximiao Formation (Lower Shaximiao Formation), Shangshaximiao Formation (Upper Shaximiao Formation), Zhenchuchong Formation, Ziliujing Formation
Location
Region Sichuan
Country China
Type section
Named for Dashanpu

The Dashanpu Formation is a Mid to Late Jurassic rock formation in China, most notable for the wealth of dinosaurs that have been excavated from the area. The Dashanpu Formation sits in and around the small township of Dashanpu (simplified Chinese: 大山铺镇; traditional Chinese: 大山鋪鎮; pinyin: Dàshānpū zhèn), situated seven kilometres north-east from Sichuan's third largest city, Zigong, in the Da'an District.

Geology[edit]

The Dashanpu Formation includes four layers of rock: The upper and lower Shaximiao Formations (simplified Chinese: ·沙溪庙地层; traditional Chinese: 上·下沙溪廟地層; pinyin: shàng / xià Shāxīmiào dìcéng), although they are commonly referred to as one, simply being called "Shaximiao Formations". The upper Shaximiao Formation is also known as the Shangshaximiao Formation, and the lower Shaximiao Formation is also known as the Xiashaximiao Formation. The Shaximiao Formations are the most productive, despite being only two of four. The last two formations, the Zhenchuchong Formation and the Ziliujing Formation, are noticeably less productive and remain relatively unexplored.

Dinosaur finds[edit]

The Dashanpu Formation has produced mainly sauropods, but has also held numerous other dinosaur types, such as theropods and stegosaurians amongst others. In total, over 8,000 pieces of bone have been unearthed from the area – amounting to nearly 40 tonnes. The site was unknown until the early 1970s, when a Chinese gas company unearthed Gasosaurus in 1972. It would be the first of the many dinosaurs to be uncovered from the area. Most specimens found are held at the Zigong Dinosaur Museum which has been placed on the area during the mid-1980s.

Despite being a frequented "dinosaur-quarry" at present, the Dashanpu Formation was once a lush forest, evidence of which has been found alongside dinosaur remains in the form of fossilised wood. Paleontologists speculate that the area also had a lake that was fed by a large river. Dinosaur remains would have been swept toward the lake over millions of years, thus accounting for the hundreds of specimens found. Paleontologists have dated parts of the formation at about 168 to 161 million years old, between the Bathonian to Callovian stages of the Mid Jurassic.

Zhiming's research[edit]

The paleontologist who has made the largest contribution to the formation and its excavation is Dong Zhiming. He first examined the formation in 1975, after bone fragments were found embedded in rock from the area. The site was being demolished to make way for both a natural gas field facility and a vehicle park when Zhiming first saw the area. Amongst the extensive clearings, Zhiming found numerous bone fragments which were exposed.

However, the specimens were being damaged due to bulldozers in the area and there would be little chance of closing the area as the state had invested millions of yuan in the site already. It was not until 1985 that the government finally agreed to close the construction on the site, and by then Zhiming and his team had already excavated over 100 dinosaurs from the area, including several rare sauropod skulls. A dinosaur found in the Dashanpu Formation, Dashanpusaurus dongi, was named in tribute of both Dashanpu and Dong Zhiming.

Paleobiota[edit]

In addition to dinosaur finds, many other prehistoric finds have been uncovered from the Dashanpu Formation. Amongst these finds are fishes, amphibians, turtles, marine reptiles such as crocodiles and also pterosaurs. Bienotheroides, a Tritylodont Synapsid has been found there, as well as Sinobrachyops, a Labyrinthodont.

Sauropterygians[edit]

Genus[1] Species[1] Stratigraphic position[1] Material Notes Images

Pliosauridae

indet.

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A pliosaurid of an indeterminate genus.[1]

Crocodyliformes[edit]

Genus[1] Species[1] Stratigraphic position[1] Material Notes Images

Teleosaurus

T. sp.

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A teleosaurid.[1]

Череп телеозавра.jpg

Sunosuchus

S. shunanensis

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A goniopholid.[1]

Sunosuchus thailandicus.jpg

Hsisosuchus

H. dashanpuensis

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A goniopholid.[1]

Zigong reptile.jpg

Pterosaurs[edit]

Genus[1] Species[1] Stratigraphic position[1] Material Notes Images

Angustinaripterus

A. longicephalus

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A rhamphorhynchoid.[1]

Angustinaripterus NT.jpg

Dinosaurs[edit]

Ornithischians[edit]

Genus[1] Species[1] Stratigraphic position[1] Material Notes Images

Agilisaurus

A. louderbacki

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

Agilisaurus louderbacki.jpg

Hexinlusaurus

H. multidens

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

Hexinlusaurus multidens.png

Xiaosaurus

X. dashanpuensis

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

Yandusaurus

Y. multidens

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

Y. hongheensis

Mamenchisaurus assemblage, Upper Shaximiao Formation

Huayangosaurus

H. taibaii

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A stegosaurian.[1]

Huayangosaurus BW.jpg

Gigantspinosaurus

G. sichuanensis

Mamenchisaurus assemblage, Upper Shaximiao Formation

A stegosaurian.[1]

G. sp.

Mamenchisaurus assemblage, Upper Shaximiao Formation

A stegosaurian.[1]

Chungkingosaurus

C. jiangbeiensis

Mamenchisaurus assemblage, Upper Shaximiao Formation

A stegosaurian.[1]

Chungkingosaurus jiangbeiensis.jpg

Tuojiangosaurus

T. multispinus

Mamenchisaurus assemblage, Upper Shaximiao Formation

A stegosaurian.[1]

Tuojiangosaurus.jpg

Chialingosaurus

C. kuani

Mamenchisaurus assemblage, Upper Shaximiao Formation

A stegosaurian.[1]

Chialingosaurus BW.jpg

Yingshanosaurus[2]

Y. jichuanensis[2]

Upper Shaximiao Formation[2]

Nearly complete skeleton[2]

A stegosaurian.[2]

Gongbusaurus

G. shiyii

Mamenchisaurus assemblage, Upper Shaximiao Formation

Sauropods[edit]

Genus[1] Species[1] Stratigraphic position[1] Material Notes Images

Shunosaurus

S. lii

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

Shunosaurus lii Finland.jpg

Protognathosaurus

P. oxyodon

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao formation

Omeisaurus

O. luoquanensis

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A mamenchisaurid.[1]

O. tianfuensis

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao formation

A mamenchisaurid.[1]

Omeisaurus tianfuensis.jpg

O. junghsiensis

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A mamenchisaurid.[1]

O. changshouensis

Mamenchisaurus assemblage, Upper Shaximiao Formation

A mamenchisaurid.[1]

O. maoi

Mamenchisaurus assemblage, Upper Shaximiao Formation

A mamenchisaurid.[1]

O. fuxiensis

Mamenchisaurus assemblage, Upper Shaximiao Formation

A mamenchisaurid.[1]

Datousaurus

D. bashanensis

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A mamenchisaurid.[1]

Datousaurus.jpg

Mamenchisaurus

M. constructus

Mamenchisaurus assemblage, Upper Shaximiao Formation

A mamenchisaurid.[1]

M. hochuanensis

Mamenchisaurus assemblage, Upper Shaximiao Formation

A mamenchisaurid.[1]

Mamenchisaurus hochuanensis Field Museum.jpg Mamench DB.jpg

M. fuxiensis

Mamenchisaurus assemblage, Upper Shaximiao Formation

A mamenchisaurid.[1]

M. anyueensis

Mamenchisaurus assemblage, Upper Shaximiao Formation

A mamenchisaurid.[1]

M. youngi

Mamenchisaurus assemblage, Upper Shaximiao Formation

A mamenchisaurid.[1]

Sauropods.jpg

M. jingyanensis

Mamenchisaurus assemblage, Upper Shaximiao Formation

A mamenchisaurid.[1]

Mamenchisaurus jingyanesi.jpg

Daanosaurus

D. zhangi

Mamenchisaurus assemblage, Upper Shaximiao Formation

Theropods[edit]

Genus[1] Species[1] Synonyms Stratigraphic position[1] Material Notes Images

Chuandongocoelurus

C. primitivus

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

Leshansaurus

L. qianweiensis

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao formation

A megalosaurid.[1]

Szechuanosaurus

S. campi

Mamenchisaurus assemblage, Upper Shaximiao Formation

A megalosaurid.[1] Remains from the Dashanpu Formation might represent an indeterminate theropod.[3]

Szechuanosaurus campi - IMG 1247.JPG

Xuanhanosaurus

X. qilixiaensis

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A megalosaurid.[1]

Kaijiangosaurus

K. lini

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A megalosaurid.[1]

Gasosaurus

G. constructus

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

Gasosaurus fossil Bishop Museum.png

Coeluroidea

gen. et sp. indet.

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

Sinocoelurus

S. fragilis

Mamenchisaurus assemblage, Upper Shaximiao Formation

Yangchuanosaurus

Y. shangyouensis

Mamenchisaurus assemblage, Upper Shaximiao formation

Yanchuanosaurus1.jpg

Y. hepingensis

Mamenchisaurus assemblage, Upper Shaximiao Formation

Probably represents a new genus.[3]

Yangchuanosaurusskull.JPG

Y. zigongensis

  • Szechuanosaurus zigongensis[3]

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

ZDM 9011 (holotype), a partial postcranial skeleton; ZDM 9012, a left maxilla; ZDM 9013, two teeth and ZDM 9014, a right hind limb.[3]

Yangchuanosaurus zigongensis.jpg

Chienkosaurus

C. ceratosauroides

Mamenchisaurus assemblage, Upper Shaximiao Formation

Chienkosaurus ulna.jpg

Turtles[edit]

Genus[1] Species[1] Stratigraphic position[1] Material Notes Images

Chengyuchelys

C. baenoides

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A chengyuchelyid.[1]

C. zigongensis

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A chengyuchelyid.[1]

C. dashanpuensis

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A chengyuchelyid.[1]

C. sp.

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A chengyuchelyid.[1]

Sichuanchelys

S. chowi

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A chengyuchelyid.[1]

Chengyuchelyidae

indet.

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

An indeterminate chengyuchelyid.[1]

Plesiochelys

P. jingyanensis

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A plesiochelyid.[1]

Plesiochelys holotype.png

Trionyx

T. sp.

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A trionychid.[1]

Therapsids[edit]

Genus[1] Species[1] Stratigraphic position[1] Material Notes Images

Bienotheroides

B. zigongensis

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A tritylodontid.[1]

Polistodon

P. chuannanensis

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

A tritylodontid.[1]

Tritylodontidae

gen. et sp. indet.

Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation

An indeterminate tritylodontid.[1]

See also[edit]

References[edit]

  1. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq ar as at au av aw ax ay az ba bb bc bd be bf bg bh bi bj bk Li, K; Liu, J.; Yang, C.; Hu, F. (2011). "Dinosaur assemblages from the Middle Jurassic Shaximiao Formation and Chuanjie Formation in the Sichuan-Yunnan Basin, China". Volumina Jurassica 9 (9): 21–42. 
  2. ^ a b c d e Zhu, S. (1994). "记四川盆地营山县一剑龙化石" [Record of a fossil stegosaur from Yingshan in the Sichuan Basin]. Sichuan Cultural Relics (S1): 8–14. 
  3. ^ a b c d e Carrano, M. T.; Benson, R. B. J.; Sampson, S. D. (2012). "The phylogeny of Tetanurae (Dinosauria: Theropoda)". Journal of Systematic Palaeontology 10 (2): 211–300. doi:10.1080/14772019.2011.630927.  edit

External links[edit]