Hekou Group

Hekou Group
Stratigraphic range: Early Cretaceous, [1] Valanginian–Albian PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geologic group
Sub-units	Huazhuang Formation, Hongkoucheng Formation, Yanguoxia Formation, Zhujiatai Formation
Underlies	Unconformity: Minhe Formation
Overlies	Unconformity: Xiangtang Formation
Thickness	3,700 m (12,100 ft)
Lithology
Primary	Sandstone, mudstone, conglomerate
Location
Coordinates	35°54′N103°18′E / 35.9°N 103.3°E / 35.9; 103.3
Approximate paleocoordinates	34°48′N103°06′E / 34.8°N 103.1°E / 34.8; 103.1
Region	Gansu
Country	China
Extent	Longzhong Basin
Hekou Group (China) Show map of China Hekou Group (Gansu) Show map of Gansu

The Hekou Group is a geological group in Gansu Province, China. It is Early Cretaceous in age. Many dinosaur fossils have been recovered from the Hekou Group, including iguanodonts, large sauropods, and armored dinosaurs. Fossil eggs are rare, but one oogenus, Polyclonoolithus , was discovered in the Hekou Group. ^[2] Extensive fossil tracks belonging to pterosaurs and dinosaurs have also been described. ^{[3] [4]} The group spans the Valanginian to Albian and can be subdivided into four formations. ^[1]

Fossil content

Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon		Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Dinosaurs

Ornithopods

Ornithopods of the Hekou Group
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Lanzhousaurus [5]	L. magnidens			A partial skeleton including the mandible, maxillary teeth, dentary teeth, cervical and dorsal vertebrae, sternal plates, ribs, and pubes	A large styracosternan iguanodontian

Sauropods

Sauropods of the Hekou Group
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Daxiatitan [6]	D. binglingi			A partial skeleton including cervical, dorsal, and caudal vertebrae, ribs, and a haemal arch, scapulocoracoid, and femur	A titanosaurian sauropod
Huanghetitan [7]	H. liujiaxiaensis			A partial skeleton including caudal vertebrae, a partial sacrum and ribs, and the left shoulder girdle	A somphospondylian sauropod
Yongjinglong [8]	Y. datangi			A partial skeleton including teeth, cervical and dorsal vertebrae, a rib, the left scapulocoracoid, and the right ulna and radius	A euhelopodid somphospondylian

Thyreophorans

Thyreophorans of the Hekou Group
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Stegosaurinae [9]	Indeterminate			A partial skeleton including cervical and dorsal vertebrae, ribs, a right forelimb (including a partial humerus, ulna, and radius), and one dermal plate [10]	An unnamed stegosaurid distinct from Wuerhosaurus and Stegosaurus stenops.
Taohelong [11]	T. jinchengensis			A partial skeleton including ribs, a left ilium, a caudal vertebra, and part of the sacral shield	A polacanthine nodosaurid

Fish

Ray-finned Fish

Ray-finned Fish of the Helou Group
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Sinamia [12]	S. lanshoensis			Many well-preserved specimens as part and counterpart fossils	A sinamiid amiiform

References

1. Xi, D.; Wan, X.; Li, G.; Li, G. (2018). "Cretaceous integrative stratigraphy and timescale of China". Science China Earth Sciences. 61: 1–31. doi:10.1007/s11430-017-9262-y.
2. Xie, J.-F., Zhang, S.-K., Jin, X.-S., Li, D.-Q., and Zhou, L.-Q. (2016) "A new type of dinosaur eggs from Early Cretaceous of Gansu Province, China. Archived 2016-01-29 at the Wayback Machine " Vertebrata PalAsiatica, 54(1):1-10.
3. Lockley, M.; Harris, J.D.; and Mitchell, L. 2008. "A global overview of pterosaur ichnology: tracksite distribution in space and time." Zitteliana. B28. p. 187-198. ISSN   1612-4138.
4. Li, Dawing; Azuma, Yoichi; Fujita, Masato; Lee, Yuong-Nam; Arakawa, Yohei (2006). "A preliminary report on two new vertebrae track sites including dinosaurs from the Early Cretaceous Hekou Group, Gansu Province, china". Journal of the Paleontological Society of Korea. 22 (1): 29–49.
5. You, Hailu; Ji, Qiang; Li, Daqing (2005). "Lanzhousaurus magnidens gen. et sp. nov. from Gansu Province, China: the largest-toothed herbivorous dinosaur in the world" [中国甘肃发现世界上最大牙齿的植食性恐龙：巨齿兰州龙(新属、新种)]. Geological Bulletin of China. 24 (9): 785–794. ISSN   1671-2552.
6. You, H.-L.; Li, D.-Q.; Zhou, L.-Q.; Ji, Q (2008). "Daxiatitan binglingi: a giant sauropod dinosaur from the Early Cretaceous of China". Gansu Geology. 17 (4): 1–10.
7. You, H.; Li, D.; Zhou, L.; Ji, Q. (2006). "Huanghetitan liujiaxiaensis. a New Sauropod Dinosaur from the Lower Cretaceous Hekou Group of Lanzhou Basin, Gansu Province, China". Geological Review. 52 (5): 668–674.
8. Li-Guo Li; Da-Qing Li; Hai-Lu You; Peter Dodson (2014). "A New Titanosaurian Sauropod from the Hekou Group (Lower Cretaceous) of the Lanzhou-Minhe Basin, Gansu Province, China". PLOS ONE. 9 (1): e85979. Bibcode:2014PLoSO...985979L. doi: 10.1371/journal.pone.0085979 . PMC   3906019 . PMID   24489684.
9. Sánchez-Fenollosa, Sergio; Cobos, Alberto (2025). "New insights into the phylogeny and skull evolution of stegosaurian dinosaurs: An extraordinary cranium from the European Late Jurassic (Dinosauria: Stegosauria)". Vertebrate Zoology. 75: 147–171. doi: 10.3897/vz.75.e146618 .
10. Li, Ning; Li, Daqing; Peng, Guangzhao; You, Hailu (2024). "The first stegosaurian dinosaur from Gansu Province, China" . Cretaceous Research . 158 (in press) 105852. Bibcode:2024CrRes.15805852L. doi:10.1016/j.cretres.2024.105852.
11. Yang J.-T.; You H.-L.; Li D.-Q.; Kong D.-L. (2013). "First discovery of polacanthine ankylosaur dinosaur in Asia" (PDF). Vertebrata PalAsiatica (in Chinese and English). 51 (4): 265–277.
12. Peng, Cuo; Murray, Alison M.; Brinkman, Donald B.; Zhang, Jiang-Yong; You, Hai-Lu (2015-03-04). "A new species of Sinamia (Amiiformes, Sinamiidae) from the Early Cretaceous of Lanzhou Basin, Gansu, China". Journal of Vertebrate Paleontology . 35 (2): e902847. Bibcode:2015JVPal..35E2847P. doi:10.1080/02724634.2014.902847. ISSN   0272-4634.

See also

• List of fossil sites
• List of dinosaur bearing rock formations