Guanling Formation

Not to be confused with Guanling biota.

The Guanling Formation is a Middle Triassic (Anisian or Pelsonian in the regional chronostratigraphy) geologic formation in southwestern China.

Guanling Formation
Stratigraphic range: early-mid Anisian (Pelsonian) ~247–245 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Geological formation
Underlies	Yangliujing Formation
Overlies	Jialingjiang Formation
Lithology
Primary	Mudstone, limestone
Other	Dolomite
Location
Coordinates	25.5°N 104.9°E / 25.5; 104.9
Approximate paleocoordinates	11.7°N 94.2°E / 11.7; 94.2
Region	Guizhou & Yunnan Provinces
Country	China
Extent	Yunnan–Guizhou Plateau
Guanling Formation (China) Show map of China Guanling Formation (Guizhou) Show map of Guizhou

Geology

The formation encompasses two members. The first member is primarily calcareous mudstone and dolomite, indicative of a coastal environment. The second member is a thicker marine sequence of dark micritic limestone with some dolomite. Two distinct fossil assemblages are found in the second member. The older Luoping biota preserves abundant arthropods (including isopods,^[1] decapods,^[2] mysidaceans and thylacocephalans^[3]) along with fossils from other invertebrates and vertebrates, which are rare but well-preserved. The slightly younger Panxian fauna has a more diverse and common assortment of marine reptiles such as sauropterygians.^[4]

A tuff bed in the Luoping biota has been dated to 244.5 ± 2.2 Ma via U-Pb SHRIMP dating. The Luoping biota as a whole was deposited over a period of 340 ± 71 kyr. This estimate is justified by cyclostratigraphic evidence, as indicated by fluctuations of terrestrial proxy metals.^[5]

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.

Among others, the following fossils were reported from the formation:

Invertebrates

Arthropoda

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.

Arthropods of the Guanling Formation
Genus	Species	Locality	Member	Material	Notes	Image
Acanthochirana[6]	A. spinifera	Luoping Biota	Upper Member	A preserved exoskeleton	An early aegerid prawn
Anisaeger [6]	A. brevirostrus	Luoping Biota	Upper Member	A preserved exoskeleton	An early aegerid prawn
Aeger	A. luxii	Luoping Biota	Upper Member	A preserved exoskeleton	An early aegerid prawn
Distaeger[6]	D prodigiosus	Luoping Biota	Upper Member	A preserved exoskeleton	An early aegerid prawn
Koryncheiros	K. luopingensis	Luoping Biota	Upper Member	A preserved exoskeleton	A clytiopsid
Protamphisopus [7]	P. baii	Dawazi, Luoping and Ranjiazhai village, Guizhou	Upper Member	A preserved exoskeleton	An amphisopid
Sinopemphix	S. guizhouensis	Dawazi, Luoping	Upper Member	A preserved exoskeleton	A pemphicid
Sinosoma	S. luopingense	Dawazi, Luoping	Member II	A preserved exoskeleton	A chilognatha
Tridactylastacus	T. sinensis	Luoping Biota	Upper Member	A preserved exoskeleton	A litogastroid
Yunnanocopia	Y. grandis	Dawazi and Shangshikan Quarry, Luoping	Upper Member	A carapace	A eucopiid crustacean
	Y. longicauda			A carapace
Yunnanolimulus	Y. luopingensis	Dawazi, Luoping	Upper Member	A carapace	A limulid (horseshoe crab)
Yunnanopalinura	Y. schrami	Luoping Biota	Upper Member	A preserved exoskeleton	An early relative of spiny lobsters

Ammonoidea

Ammonites of the Guanling Formation
Genus	Species	Locality	Member	Material	Notes	Image
Progonoceratites	P. pulcher	Guizhou		A fossilized shell	A ceratitid ammonite

Bivalvia

Bivalves of the Guanling Formation
Genus	Species	Locality	Member	Material	Notes	Image
Asoella	A. illyrica
Eumorphotis	E. (Asoella) paradoxica
Myophoria	M. (Costatoria) goldfussi
Pleuromya	P. elongata

Brachiopoda

Brachiopods of the Guanling Formation
Genus	Species	Locality	Member	Material	Notes	Image
Lingula	L. deitersensis
	L. marginia
	L. polaris
Pseudospiriferina	P. multicostata
	P. pinguis
Punctospirella	P. fragilis

Echinoidea

Sea Urchins of the Guanling Formation
Genus	Species	Locality	Member	Material	Notes	Image
Yunnanechinus[8]	Y. luopingensis	Luoping Biota, Yunnan	Member II	A specimen	An early sea urchin

Vertebrates

Fish

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.

Actinopterygii

Ray-finned fish of the Guanling Formation
Genus	Species	Locality	Member	Material	Notes	Image
Altisolepis	A. sinensis	Dawazi, Yunnan	Upper Member	A skeleton	A peltopleurid bony fish	Frodoichthys luopingensis Luoxiongichthys hyperdorsalis
Diandongichthys[9]	D. ocellatus	Luoping, Yunnan	Upper Member	A complete, laterally compressed specimen	A basal ginglymodian
Diandongperleidus	D. denticulatus	Dawazi, Yunnan	Upper Member	A preserved skeleton	A perleidiform
Feroxichthys	F. panzhouensis	Xinmin, Panxian	Upper Member	A skeleton	A colobodontid
	F. yunnanensis	Luoping Biota, Yunnan		A skeleton
Frodoichthys	F. luopingensis	Dawazi village, Yunnan	Upper Member	A skeleton	An early neopterygian
Fuyuanperleidus	F. dengi	Dawazi village, Yunnan	Upper Member	A skeleton	A fuyuanperleidid
Gimlichthys	G. dawaziensis	Dawazi village, Yunnan	Upper Member	A skeleton	An early neopterygian
Gymnoichthys	G. inopinatus	Dawazi village, Yunnan	Upper Member	A skeleton	An amiiform
Habroichthys	H. broughi	Dawazi village, Yunnan	Upper Member	A skeleton	A peltopleuriform
Kyphosichthys[10]	K. grandei	Luoping, eastern Yunnan Province	Upper Member	A complete preserved skeleton	A kyphosichthyiform
Lashanichthys[11]	L. sui	Yangjuan, Guizhou	Upper Member	A partial skeleton	A lashanichthyid
	L. yangjuanensis	Dawazi Village, Yunnan	Upper Member	A skeleton
Luopingichthys	L. bergi	Dawazi Village, Yunnan	Member II	A skeleton	A louwoichthyiform
Luoxiongichthys	L. hyperdorsalis	Luoxiong Town, Yunnan	Lower member	A nearly complete skeleton and skull, a partial skull, and other referred materials	A halecomorph
Louwoichthys	L. pusillus	Yunnan	Member II	A skeleton	A louwoichthyid fish
Luopingperleidus	L. sui	Dawazi, Yunnan	Upper Member	A skeleton	A perleidid
Marcopoloichthys[12]	M. ani	Dawazi village, Yunnan	Upper Member	A complete specimen	A teleosteomorph
Panxianichthys	P. imparilis	Xinmin, Guizhou and Yanjuan	Upper Member	A skeleton	A panxianichthyiform
Perleidus[13]	P. sinensis	Dawazi village, Yunnan	Upper Member	A specimen	A perleidid
Platysiagum	P. sinensis	Dawazi, Yunnan	Upper Member	A skeleton	A platysiagid
Pteronisculus	P. changae	Dawazi village, Yunnan	Upper Member	A skeleton	An early ray-finned fish of uncertain affinites
	P. nielseni[14]	Luoping Biota, Yunnan		A skeleton
Robustichthys	R. luopingensis	Luoping Biota, Yunnan	Upper Member	A skeleton	A Ionoscopiform
Saurichthys	S. dawaziensis	Dawazi village, Yunnan	Upper member	A broad skull and crushing dentition	A saurichthyiform
	S. spinosa
Sinosaurichthys	S. longimedialis	Yangjuan, Guizhou and Dawazi of Luoping, Yunnan	Upper Member	A skeleton	A saurichthyiform
	S. longipectoralis			A skeleton
	S. minuta			A skeleton
Subortichthys	S. triassicus	Luoping biota, Yunnan	Member II	A skeleton	A subortichthyid
Venusichthys[15]	V. comptus	Luoping biota, Yunnan	Member II	Multiple skeletons	A neopterygian in the monotypic family Venusichthyidae
Yelangichthys	Y. macrocephalus	Xindian, Guizhou	Upper Member	A broad skull and crushing dentition.	A saurichthyiform
Yudaiichthys [11]	Y. eximius	Luoping biota, Yunnan	Member II	A skeleton	A lashanichthyid

Sarcopterygii

Lobe-finned fish of the Guanling Formation
Genus	Species	Locality	Member	Material	Notes	Image
Luopingcoelacanthus	L. eurylacrimalis	Luoping Biota, Yunnan	Upper Member	Multiple skeletons	A coelacanthiform	Luopingcoelacanthus eurylacrimalis
Yunnancoelacanthus	Y. acrotuberculatus	Luoping Biota, Yunnan	Upper Member	A skeleton	A coelacanthiform

Reptiles

Ichthyosauria

Ichthyosaurs of the Guanling Formation
Genus	Species	Locality	Member	Materials	Notes	Image
Barracudasauroides[16]	B. panxianensis	Yangjuan village, Xinmin	Upper Member[16][4]	A skeleton	A small mixosaurid ichthyosaur; either a member of its own genus[17] or a species of Mixosaurus.[4]	Barracudasauroides Phalarodon Mixosaurus
Mixosaurus	M. kuhnschnyderi	Xinzhai Village, Luoping	Upper Member	A specimen	A small mixosaurid ichthyosaur
	M. luxiensis	Huale Village, Luxi	Upper Member	A largely complete but disarticulated skeleton
	M. panxianensis	Yangjuan Hill locality	Middle Member	A skeleton
	M. xindianensis	Xindian, Qingshan Pu'an	Upper Member
Phalarodon[18][19]	P. atavus[19]		Upper Member[4]	A complete skeleton	A small mixosaurid ichthyosaur; might represent a member of its own genus, Contectopalatus.
	P. fraasi[18]	Yangjuan Village	Upper Member[4]	A skull with durophagous dentition.	A small mixosaurid ichthyosaur
Xinminosaurus[20]	X. catactes	Near Yangjuan Village, Guizhou	Upper Member[4]	A nearly complete skeleton	A medium-sized early ichthyosaur with durophagous dentition, possibly a member of Cymbospondylidae.

Pseudosuchia

Pseudosuchians of the Guanling Formation
Genus	Species	Locality	Member	Materials	Notes	Image
Chirotherium	C. bartheii	Zhenfeng County, Guizhou	Upper Member	Several trackways	A pseudosuchian archosaur	Qianosuchus
Qianosuchus	Q. mixtus	Xinmin, Panxian		Two nearly complete skeletons and a crushed skull	An aquatic poposauroid archosaur

Sauropterygia

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.

Nothosauria

Nothosaurs of the Guanling Formation
Genus	Species	Locality	Member	Materials	Notes	Image
Dawazisaurus	D. brevis	Dawazisaurus-type locality, Yunnan	Member II	A nearly complete skeleton exposed in dorsal view	A sauropterygian of possible nothosauroid affinities	Dawazisaurus Nothosaurus
Dikoposichnus[21]	D. luopingensis	Qingyuan Village, Guizhou, and Luoping Biota, Yunnan	Member I	12 trackways and footprints	A probable nothosaur ichnotaxon
Lariosaurus[22]	L. hongguoensis	Yangjuan village, Guizhou	Upper Member	A near-complete skeleton	A small Lariosaurinae nothosaur
Nothosaurus	N. rostellatus[23]	Panxian, Guizhou	Upper Member	A complete skull and incomplete postcranial skeleton	A nothosaur
	N. yangjuanensis	Panxian, Guizhou	Middle Member	A partial skeleton
	N. zhangi[24]	Bed 165 of the Dawazi section, Yunnan	Upper Member	A complete lower jaw associated with a partial postcranial skeleton
Sanchiaosaurus	S. dengi	Sanchiao in the vicinity of Guiyang and Chinchungchiao, Guizhou	Middle member	A partial skeleton	A nothosaur

Pachypleurosauria

Pachypleurosaurs of the Guanling Formation
Genus	Species	Locality	Member	Materials	Notes	Image
Diandongosaurus	D. acutidentatus	Dawazi, Yunnan	Member II	A complete and articulated skeleton with skull	A small pachypleurosaur	Luopingosaurus Wumengosaurus
Dianopachysaurus	D. dingi	Dawazi, Luoping	Member II	A near-complete articulated skeleton	A keichousaurid pachypleurosaur
Dianmeisaurus	D. gracilis	Luoping, Yunnan	Upper Member	A small skeleton likely belonging to an immature individual	A pachypleurosaur
	D. mutaensis	Northwest of Muta village, Luxi		A complete and articulated skeleton exposed in dorsal view
Honghesaurus	H. longicaudalis	Luxi, Yunnan	Member II	A skeleton	A pachypleurosaurid
Luopingosaurus[25]	L. imparilis	Luoping, Yunnan	Upper Member	A skeleton	A pachypleurosaurid
Panzhousaurus[26]	P. rotundirostris	Dapianpo Quarry from Yangjuan Village, Guizhou	Upper Member	A near-complete skeleton	A pachypleurosaur
Wumengosaurus	W. delicatomandibularis	Yangjuan Village, Xinmin	Member II	A skeleton	A small pachypleurosaur
	W. rotundicarpus	Panzhou, Guizhou	Member II	A specimen

Placodontiformes

Placodontiformes of the Guanling Formation
Genus	Species	Locality	Member	Materials	Notes	Image
Atopodentatus[27]	A. unicus	Dawazi, Yunnan	Upper Member and Member II[27]	Several well-preserved specimens	A bizarre, likely herbivorous[28] sauropterygian with possible placodontiform affinities[29]	Atopodentatus Placodus
Placodus[30]	P. inexpectatus	Yangjuan Village, Xinmin	Upper Member[30][4]	A skeleton	A medium-sized placodontid placodont, known from a[30]

Saurosphargidae

Saurosphargidae of the Guanling Formation
Genus	Species	Locality	Member	Materials	Notes	Image
Anshunpes[21]	A. aquacursor	Qingyuan Village, Guizhou	Songzikan Member (Member I)	A trackway consisting of 10 right and 9 left autopodial (?manus) imprints	An ichnotaxon of Saurosphargidae	Sinosaurosphargis
Largocephalosaurus	L. polycarpon[31]	Luoping, Yunnan	Upper Member [31][4]	A nearly complete and articulated skull and skeleton missing most of its tail	A mid-sized basal saurosphargid sauropterygian
	L. qianensis[32]	Panxian, Gauizhou	Upper Member [32][4]	Multiple specimens	A mid-sized basal saurosphargid sauropterygian
Sinosaurosphargis[33]	S. yunguinensis	Yangmazhai of Luoping County, Yunnan and Yangjian of Pan County, Guizhou	Upper Member [33][4]	Multiple specimens	A small armoured saurosphargid sauropterygian

Tanysauria

Tanysaurians of the Guanling Formation
Genus	Species	Locality	Member	Materials	Notes	Image
Austronaga[34]	A. minuta	Waina Village, Yunnan	Member II	A nearly complete skull articulated, the first six cervical vertebrae, and 65 caudal vertebrae	A trachelosaurid	Dinocephalosaurus Pectodens
Dinocephalosaurus[35]	D. orientalis	Paxian, Gaizhou and Luoping, Yunnan	Member II	Multiple specimens	A trachelosaurid
Gracilicollum[36]	G. latens	Near Xinmin Village in Panzhou, Guizhou	Member II	A skull and partial neck	A probable trachelosaurid
Luxisaurus[35]	L. terrestris	Near Suomeiluo in Luxi County, Yunnan	Upper Member	An articulated partial skeleton	A tanystropheid
Pectodens[35]	P. zhenyuensis	Luoping, Yunnan	Member II	A well-preserved and near-complete skeleton	A small trachelosaurid