The Zhuganpo Formation is a

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

geologic unit A stratigraphic unit is a volume of rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features (facies) that characterize ...

found in southern

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

. It has historically been known as the Zhuganpo Member of the Falang Formation. A diverse fossil assemblage known as the Xingyi biota or Xingyi Fauna can be found in the upper part of the Zhuganpo Formation. Fossils of the Xingyi biota include articulated skeletons of marine reptiles, abundant fish, and a plentiful assortment of

invertebrates Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordate subphylum ...

indicating a

Ladinian The Ladinian is a stage and age in the Middle Triassic series or epoch. It spans the time between Ma and ~237 Ma (million years ago). The Ladinian was preceded by the Anisian and succeeded by the Carnian (part of the Upper or Late Triassic ...

Carnian The Carnian (less commonly, Karnian) is the lowermost stage (stratigraphy), stage of the Upper Triassic series (stratigraphy), Series (or earliest age (geology), age of the Late Triassic Epoch (reference date), Epoch). It lasted from 237 to 227.3 ...

age for the sediments of the formation.

Paleobiota

Invertebrates

Ammonites Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...

: '' Clionitites'' sp., '' Detoniceras'' sp., '' Haoceras xingyiense'', '' Parasturia'' sp., ''

Protrachyceras ''Protrachyceras'' is a genus of ceratitid ammonoid cephalopods belonging to the family Trachyceratidae. Species *''Protrachyceras costulatum'' Mansuy 1912 *''Protrachyceras deprati'' Mansuy 1912 *''Protrachyceras reitzi'' Boeckh 1875 *''Protrac ...

'' sp., '' Ptychites'' sp., '' Sinomeginoceras'' (''S. wangi, S. xingyiense''), ''

Trachyceras ''Trachyceras'' is a genus of ammonoid cephalopods belonging to the order Ceratitida. The type species is ''Trachyceras aon'', which was first described by Georg zu Münster in 1834 as a species of ''Ceratites''. The genus includes many species ...

'' sp., '' Xenoprotrachyceras'' cf. ''primum'', '' Yangites densicostatus'', *

Bivalves Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed by a calcified exoskeleton consis ...

: '' Daonella'' sp. *

Conodont Conodonts, are an extinct group of marine jawless vertebrates belonging to the class Conodonta (from Ancient Greek κῶνος (''kōnos''), meaning " cone", and ὀδούς (''odoús''), meaning "tooth"). They are primarily known from their hard ...

s: '' Gladigondolella malayensis'', ''

Metapolygnathus ''Metapolygnathus'' is an extinct genus of platform conodonts. Synonyms '' Mazzaella'' is a new genus that also includes ''Metapolygnathus baloghi'' Kovacs (1977). Use in stratigraphy The top of the Carnian or the base of the Norian The ...

'' / '' Paragondolella'' / '' Quadralella'' (''Q.'' aff''. acuminatus, P. foliata, P. inclinata, Q. intermedius, Q. langdaiensis, P. maantangensis, P. navicula, M. nodosus, M. parafoliata, Q.'' aff''. praelindae, P. polygnathiformis, Q. shijiangjunensis, Q. tadpole,'' ''Q. uniformis, Q. wanlanensis, Q.'' aff''. wayaoensis, Q. yongueensis, Q.'' aff. ''zonneveldi'') *

Crinoid Crinoids are marine invertebrates that make up the class Crinoidea. Crinoids that remain attached to the sea floor by a stalk in their adult form are commonly called sea lilies, while the unstalked forms, called feather stars or comatulids, are ...

s: '' Traumatocrinus hsui'' *

Crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s ("shrimps"): '' Schimperella acanthocercus'' (

Lophogastrida Lophogastrida is an Order (biology), order of malacostracan crustaceans in the superorder Peracarida, comprising shrimp-like animals that mostly inhabit the relatively deep pelagic waters of the oceans throughout the world. Most lophogastridan s ...

)''''

Fish

Acrolepidae Acrolepididae is an extinct family (biology), family of ray-finned fish. Genera referred to Acrolepididae existed from the Early Carboniferous period (geology), period to the Early Triassic epoch (geology), epoch. They were nektonic carnivores wi ...

indet.'''' * '' Archaesemionotus'' sp''.'' * aff. '' Arctacanthus'' sp. ( Chimaeriformes?) * '' Asialepidotus shingyiensis'' ( Ionoscopiformes)'''' * '' Birgeria liui'' *

Caturidae Caturidae is an extinct Family (biology), family of predatory Amiiformes, amiiform Actinopterygii, ray-finned fish, being the sister-group to the extant family Amiidae. Though their body form is very different than the modern bowfin, a number of f ...

indet.'''' * ''

Eosemionotus ''Eosemionotus'' ("dawn ''Semionotus''") is an extinct genus of prehistoric marine macrosemiid ray-finned fish from the Middle Triassic (Anisian to Ladinian). It was a speciose genus known from throughout Europe, including formations of the Musc ...

'' sp''.'' * '' Favusodus orientalis'' (

Euselachii Elasmobranchii () is a subclass of Chondrichthyes or cartilaginous fish, including modern sharks ( division Selachii), and batomorphs (division Batomorphi, including rays, skates, and sawfish). Members of this subclass are characterised by h ...

)'''' * '' Fuyuanichthys wangi'' (

Ginglymodi Ginglymodi is a clade of ray-finned fish containing modern-day gars (Lepisosteidae) and their extinct relatives (including the family (biology), family Lepidotidae) in the Order (biology), order Lepisosteiformes, the extinct orders Semionotiforme ...

) * '' Fuyuanperleidus dengi'' * '' Guizhouamia bellula'' * '' Guizhoubrachysomus minor'' * '' Guizhoucoelacanthus guanlingensis'' * '' Guizhouniscus microlepidus'' * ''

Habroichthys ''Habroichthys'' is an extinct genus of prehistoric bony fish that lived during the early Ladinian stage of the Middle Triassic epoch, 242 to 232 million years ago. It has been found in Austria, China, Italy, Slovenia, and Switzerland. It was a s ...

'' sp''.'' * '' Keichouodus nimaiguensis'' (Euselachii)'''' * '' Luganoia fortuna'' ( Luganoiidae) * '' Malingichthys'' (''M. nimaiguensis, M. wanfendlinensis'';

Pholidophoridae Pholidophoridae is an extinct family of primitive stem-teleost fish that lived during the Triassic period, from the Anisian age of the Middle Triassic to the Norian age of the Late Triassic. Most of the genera are from Europe, but one ('' Malingi ...

) * '' Marcopoloichthys'' sp''.'' * '' Peltopleurus (P. orientalis, P. tyrannos)'' * '' Peripeltopleurus'' sp''.'' ( Wushaichthyidae) *

indet.'''' * '' Potanichthys xingyiensis'' (

Thoracopteridae Thoracopteridae is an extinct family of prehistoric bony fish classified with the order Peltopleuriformes, containing four genera: ''Thoracopterus'', ''Gigantopterus'', ''Potanichthys'' and ''Italopterus''. This lineage of Triassic flying fish-li ...

)'''' * '' Rosaodus xingyiensis'' (

Elasmobranchii Elasmobranchii () is a subclass of Chondrichthyes or cartilaginous fish, including modern sharks ( division Selachii), and batomorphs (division Batomorphi, including rays, skates, and sawfish). Members of this subclass are characterised by h ...

) * ''

Saurichthys ''Saurichthys'' (from , 'lizard' and 'fish') is an extinct genus of predatory Actinopterygii, ray-finned fish from the Triassic period (geology), Period. It is the type genus of the family (taxonomy), family Saurichthyidae (Changhsingian-Ju ...

'' sp''.'' * '' Sinoeugnathus kueichowensis'' * '' Wushaichthys exquisitus'' (Wushaichthyidae) * '' Xingyia gracilis''

Reptiles

References

{{reflist Geologic formations of China Triassic System of Asia Triassic China Carnian Stage Ladinian Stage Paleontology in Guizhou Paleontology in Yunnan