The Guanling Formation is a Middle Triassic (Anisian or Pelsonian in the regional chronostratigraphy) geologic formation in southwestern China.
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, decapods, mysidaceans and thylacocephalans) 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.
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.
Fossil content
Among others, the following fossils were reported from the formation: Invertebrates Arthropoda Arthropods of the Guanling Formation Genus Species Locality Member Material Notes ImageAcanthochiranaA. spiniferaLuoping BiotaUpper MemberA preserved exoskeletonAn early aegerid prawnAnisaeger Schweitzer, Carrie E.; Feldmann, Rodney M.; Hu, Shixue; Huang, Jinyuan; Zhou, Changyong; Zhang, Qiyue; Wen, Wen; Xie, Tao (May 2014). "Penaeoid Decapoda (Dendrobranchiata) from the Luoping Biota (Middle Triassic) of China: Systematics and Taphonomic Framework". Journal of Paleontology. 88 (3): 457–474. Bibcode:2014JPal...88..457S. doi:10.1666/13-039. S2CID 128636280. Retrieved 14 March 2023.A. brevirostrus Luoping Biota Upper Member A preserved exoskeleton An early aegerid prawnAegerA. luxii Luoping Biota Upper Member A preserved exoskeleton An early aegerid prawnAtropicarisA. sinensisLuoping BiotaUpper MemberA thylacocephalanDistaegerD prodigiosusLuoping BiotaUpper Member A preserved exoskeleton An early aegerid prawn JudahellaMarie-Béatrice Forel, Jinyuan Huang, Jianxin Yu, Junyu Wan, Qiyue Zhang, et al.. Middle Triassic ostracods from Yunnan, South China. Alcheringa, 2025, pp.1-16. ⟨10.1080/03115518.2025.2488055⟩. ⟨hal-05210996⟩J. leii Yunnan Upper Member A specimen An early ostracodKoryncheirosK. luopingensis Luoping Biota Upper Member A preserved exoskeleton A clytiopsidProtamphisopus W. L. Fu and G. D. F. Wilson. 2010. Taxonomic names, in A new species of Protamphisophus Nicholls (Crustacea, Isopoda, Phreatoicidea) from Middle Triassic Luoping fauna of Yunnan Province, China. Journal of Paleontology 84(5):1003-1013P. baii Dawazi, Luoping and Ranjiazhai village, Guizhou Upper Member A preserved exoskeleton An amphisopid SinopemphixS. guizhouensis Dawazi, Luoping Upper Member A preserved exoskeleton A pemphicidSinosomaS. luopingense Dawazi, Luoping Member II A preserved exoskeleton A chilognathaTridactylastacusT. sinensis Luoping Biota Upper Member A preserved exoskeleton A litogastroid YunnanocopiaY. grandis Dawazi and Shangshikan Quarry, Luoping Upper Member A carapaceA eucopiid crustaceanY. longicauda A carapaceYunnanolimulusY. luopingensis Dawazi, Luoping Upper Member A carapace A limulid (horseshoe crab) YunnanopalinuraY. 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 ImageProgonoceratitesP. pulcher Guizhou A fossilized shell A ceratitid ammonite
Bivalvia Bivalves of the Guanling Formation Genus Species Locality Member Material Notes ImageAsoellaA. illyricaEumorphotisE. (Asoella) paradoxicaMyophoriaM. (Costatoria) goldfussiPleuromyaP. elongata Brachiopoda Brachiopods of the Guanling Formation Genus Species Locality Member Material Notes ImageLingulaL. deitersensisL. marginiaL. polarisPseudospiriferinaP. multicostataP. pinguisPunctospirella P. fragilis Echinoidea Sea Urchins of the Guanling Formation Genus Species Locality Member Material Notes ImageYunnanechinusJ. R. Thompson, S. X. Hu, Q. Y. Zhang, E. Petsios, L. J. Cotton, J. Y. Huang, C. Y. Zho, W. Wen, and D. J. Bottjer. 2018. A new stem group echinoid from the Triassic of China leads to a revised macroevolutionary history of echinoids during the end-Permian mass extinction. Royal Society Open Science 5:171548Y. luopingensis Luoping Biota, Yunnan Member II A specimen An early sea urchin
Vertebrates Fish
Actinopterygii Ray-finned fish of the Guanling Formation Genus Species Locality Member Material Notes ImageAltisolepisA. sinensis Dawazi, Yunnan Upper Member A skeleton A peltopleurid bony fish Diandongichthys D. ocellatus Luoping, Yunnan Upper Member A complete, laterally compressed specimen A basal ginglymodianDiandongperleidusD. denticulatus Dawazi, Yunnan Upper Member A preserved skeleton A perleidiformFeroxichthysF. panzhouensis Xinmin, Panxian Upper Member A skeleton A colobodontidF. yunnanensis Luoping Biota, Yunnan A skeletonFrodoichthysF. luopingensisDawazi village, Yunnan Upper Member A skeleton An early neopterygian FuyuanperleidusF. dengiDawazi village, YunnanUpper Member A skeleton A fuyuanperleididGimlichthysG. dawaziensis Dawazi village, Yunnan Upper Member A skeleton An early neopterygian GymnoichthysG. inopinatus Dawazi village, Yunnan Upper Member A skeleton An amiiformHabroichthysH. broughi Dawazi village, Yunnan Upper Member A skeleton A peltopleuriformKyphosichthysXu, Guang-Hui & Wu, Feixiang. (2012). A deep-bodied ginglymodian fish from the Middle Triassic of eastern Yunnan Province, China, and the phylogeny of lower neopterygians. Chinese Science Bulletin. 57. 10.1007/s11434-011-4719-1. K. grandei Luoping, eastern Yunnan Province Upper Member A complete preserved skeleton A kyphosichthyiform LashanichthysL. sui Yangjuan, Guizhou Upper Member A partial skeletonA lashanichthyidL. yangjuanensis Dawazi Village, Yunnan Upper Member A skeletonLuopingichthysL. bergi Dawazi Village, Yunnan Member II A skeleton A louwoichthyiformLuoxiongichthysL. hyperdorsalisLuoxiong Town, Yunnan Lower member A nearly complete skeleton and skull, a partial skull, and other referred materials A halecomorph LouwoichthysL. pusillus Yunnan Member II A skeletonA louwoichthyid fishLuopingperleidusL. sui Dawazi, Yunnan Upper Member A skeleton A perleididMarcopoloichthysTintori, Andrea; Sun, Zuo-Yu; Lombardo, Cristina; Jiang, Da-Yong; Sun, Yuan-Lin; Rusconi, Marco; Hao, Wei-cheng (2007). "NEW SPECIALIZED BASAL NEOPTERYGIANS (ACTINOPTERYGII) FROM TRIASSIC OF THE TETHYS REALM". Geol. Insubr. 10 (2) – via ResearchGate.M. ani Dawazi village, Yunnan Upper MemberA complete specimen A teleosteomorphPanxianichthysP. imparilis Xinmin, Guizhou and Yanjuan Upper Member A skeleton A panxianichthyiformPerleidusYuan, Z.; Xu, G.; Dai, X.; Wang, F.; Liu, X.; Jia, E.; Miao, L.; Song, H. (2022). "A new perleidid neopterygian fish from the Early Triassic (Dienerian, Induan) of South China, with a reassessment of the relationships of Perleidiformes". PeerJ. 10 e13448. doi:10.7717/peerj.13448. PMC 9121871. PMID 35602899.P. sinensis Dawazi village, Yunnan Upper Member A specimen A perleididPlatysiagumP. sinensis Dawazi, Yunnan Upper Member A skeleton A platysiagidPteronisculusP. changae Dawazi village, YunnanUpper Member A skeleton An early ray-finned fish of uncertain affinitesP. nielseniXu, Guang-Hui; Shen, Chen-Chen; Zhao, Li-Jun (2014). "Pteronisculus nielseni sp. nov., a new stem-actinopteran fish from the Middle Triassic of Luoping, Yunnan Province, China". Vertebrata PalAsiatica. 52: 364–380. Luoping Biota, Yunnan A skeletonPtycholepisP. huoae Luoping Biota, Yunnan Upper Member A ptycholepiformRobustichthys R. luopingensisLuoping Biota, YunnanUpper MemberA skeletonA IonoscopiformSaurichthysS. dawaziensisDawazi village, YunnanUpper member A broad skull and crushing dentition A saurichthyiformS. spinosaSinosaurichthysS. longimedialisYangjuan, Guizhou and Dawazi of Luoping, Yunnan Upper Member A skeleton A saurichthyiform S. longipectoralis A skeleton S. minuta A skeletonSubortichthysS. triassicus Luoping biota, Yunnan Member IIA skeletonA subortichthyidVenusichthysV. comptus Luoping biota, Yunnan Member II Multiple skeletons A neopterygian in the monotypic family Venusichthyidae YelangichthysY. macrocephalus Xindian, Guizhou Upper Member A broad skull and crushing dentition. A saurichthyiformYudaiichthys Y. eximius Luoping biota, Yunnan Member II A skeletonA lashanichthyid
Sarcopterygii Lobe-finned fish of the Guanling Formation Genus Species Locality Member Material Notes ImageLuopingcoelacanthusL. eurylacrimalis Luoping Biota, Yunnan Upper Member Multiple skeletons A coelacanthiform YunnancoelacanthusY. acrotuberculatus Luoping Biota, Yunnan Upper Member A skeleton A coelacanthiform
Reptiles Ichthyosauria Ichthyosaurs of the Guanling Formation Genus Species Locality Member Materials Notes ImageBarracudasauroides B. panxianensis Yangjuan village, Xinmin Upper Member A skeleton A small mixosaurid ichthyosaur; either a member of its own genus or a species of Mixosaurus. MixosaurusM. kuhnschnyderi Xinzhai Village, Luoping Upper Member A specimen A small mixosaurid ichthyosaurM. luxiensisHuale Village, Luxi Upper Member A largely complete but disarticulated skeletonM. panxianensis Yangjuan Hill locality Middle Member A skeletonM. xindianensis Xindian, Qingshan Pu'an Upper Member Phalarodon P. atavus Upper Member A complete skeleton A small mixosaurid ichthyosaur; might represent a member of its own genus, Contectopalatus. P. fraasi Yangjuan Village Upper Member A skull with durophagous dentition. A small mixosaurid ichthyosaur Xinminosaurus X. catactes Near Yangjuan Village, Guizhou Upper Member 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 ImageChirotheriumC. bartheiiZhenfeng County, GuizhouUpper MemberSeveral trackwaysstyle="background:#FEF6E4;"| A pseudosuchian archosaur | rowspan = 100| |- |Qianosuchus|Q. mixtus'' Xinmin, Panxian Two nearly complete skeletons and a crushed skull An aquatic poposauroid archosaur
Sauropterygia
Nothosauria