Dengying Formation

The Dengying Formation is an upper Ediacaran (551-541 Ma^[2]) fossiliferous geologic formation found in South China. It was deposited on a shallow marine carbonate platform.^[3]

Dengying Formation
Stratigraphic range: Ediacaran ~551–541 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Transition between uppermost Doushantuo Formation and lowermost Dengying Formation
Type	Formation
Sub-units	See: Members
Underlies	Yanjiahe Formation[1]
Overlies	Doushantuo Formation
Location
Region	Yangtze Gorges
Country	China

Members

Listed by ascending age:

• The Hamajing Member is characterized by light grey, medium- to thick-bedded dolomite, intercalated with thin layers of chert.^[3]
• The Shibantan Member is interpreted to represent a subtidal environment and is composed of dark grey, thin-bedded bituminous limestone. It is the most fossiliferous of the Dengying Formation members and has yielded several trace fossils, such as Lamonte,^[4] as well as possible lobopodian trackways. ^[5]
• The Baimatuo Member consists of light grey, thick-bedded dolomite.^[3]

Traditionally, the Tianzhushan Member was considered to be the uppermost unit of the Dengying Formation. However, its small shelly fossils and Micrhystridium-like acritarchs are a shared characteristic with the Cambrian Yanjiahe Formation.^[3] The Kuanchuanpu Formation also is occasionally placed as a member of the Dengying Formation,^[6] however it is likely separate for the same reasons.

Paleobiota

The Dengying formation is unique from other Ediacaran formations in that its top is almost right up against the Ediacaran - Cambrian boundary, with more recent organisms being described that have striking similarities with Cambrian fauna, like Alienum. There are also a lot of ichnogenera in the form of burrows, something that is common in younger Ediacaran rocks the closer to the Cambrian boundary they are.

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.

Proarticulata

Genus	Species	Notes	Images
Dickinsonia[7]	Dickinsonia sp.	Oval to elongated motile organism. Only one incomplete specimen is known.

Petalonamae

Genus	Species	Notes	Images
Charniodiscus[8]	Charniodiscus sp.	Frondose organism.
Paracharnia[9]	P. denyingensis	Frondose organism.
Pteridinium[8]	Pteridinium sp.	Frondose organism.
Rangea[8]	Rangea sp.	Frondose organism.

Trilobozoa

Genus	Species	Notes	Images
Lobodiscus[10]	L. tribrachialis	Tri-radial organism.

Porifera

Genus	Species	Notes	Images
Helicolocellus[11]	H. cantori	Conical sponge, possible relations to hexactinelliid sponges.

incertae sedis

Genus	Species	Notes	Images
Alienum[12]	A. velamenus	Vetulicolian-like organism.
Cloudina[13]	Cloudina sp.	Tubular organism.
Curviacus[14]	C. ediacaranus	Elongated organism.
Conotubus[15]	C. hemiannulatus	Tubular organism.
Cycliomedusa[16]	C. jiangchuanensis	Discoid organism.
Gaojiashania[17]	G. cyclus	Tubular organism.
Hiemalora[8]	Hiemalora sp.	Discoid organism, possibly holdfasts of petalonamids.
Palaeorhopalon[13]	P. spiniferum	Tubular organism.
Shufangtubulus[13]	S. inornatus	Tubular organism.
Sinotubulites[18][13]	Sinotubulites sp. S. baimatuoensis S. hexagonus S. pentacarinalis S. triangularis	Tubular organism.
Wutubus[8]	W. annularis	Tubular organism.
Yangtziramulus[19]	Y. zhangi	Enigmatic organism, affinities with other forms is unknown, although possibly related to the Petalonamae, like Charnia.
Yilingia[20]	Y. spiciformis	Bilterian animal of unknown affinities, with possible relations to Panarthopoda or Annelida.

Flora

Genus	Species	Notes	Images
Longfengshania[16]	Longfengshania sp.	Thallus-like macroalgae.
Protocodium[21]	P. sinense	Codiacean alga.

Microorganisms

Genus	Species	Notes	Images
Protolagena[22]	P. limbata P. gaojiashanensis P. papillatus	Vase-like microorganisms.
Sicylagena[22]	S. formosa S. latistoma	Vase-like microorganisms.

Ichnogenera

Genus	Species	Notes	Images
Lamonte[23]	L. trevallis	Burrows.
Helminthoidichnites	Helminthoidichnites isp.	Burrows.
Shaanxilithes	Shaanxilithes isp.	Junior synonym of Nenoxites.
Nenoxites	Nenoxites isp.	Movement traces.
Torrowangea	Torrowangea isp.	Burrows.

Undescribed

Genus	Species	Notes	Images
Zhenba columns[24]	???	Possible affinities with coralline algae.
Bilateria indet.	Unapplicable	Known to have several pairs of appendages, but its exact affinity is unknown[25]

See also

• List of fossiliferous stratigraphic units in China
• Ediacaran biota