| System (period) | Series | Stage (age) | Lower boundary, Ma | |
|---|---|---|---|---|
| Triassic | Lower | Induan | 251.902±0.024 | |
| Permian | Lopingian | Changhsingian |  254.14±0.07
| |
| Wuchiapingian | 259.51±0.21
| |||
| Guadalupian | Capitanian | 264.28±0.16
| ||
| Wordian | 266.9±0.4
| |||
| Roadian | 273.01±0.14
| |||
| Cisuralian | Kungurian | 283.5±0.6 | ||
| Artinskian | 290.1±0.26
| |||
| Sakmarian | 293.52±0.17
| |||
| Asselian | 298.9±0.15
| |||
| Carb. | Pen. | Upper | Gzhelian | older |
| Subdivisions and "golden spikes" according to IUGS as of September 2023[1] | ||||
The Wuchiapingian is a lower stage of the Lopingian series, corresponding to the Wuchiapingian age of the Lopingian epoch. It lasted from approximately 259.51 Ma to around 254.14 Ma (million years ago). It is preceded by the Capitanian age of the Guadalupian and is followed by the Changhsingian age of the Lopingian. The beginning of the Wuchiapingian corresponds to the Capitanian (Guadalupian-Lopingian) mass extinction. The last embolomeres, nectrideans, diadectomorphs and dinocephalians as well as the earliest procolophonids are known from this stage.
Definition[]
The GSSP of the Wuchiapingian stage and the whole Lopingian series was ratified in 2004. The lower boundary is fixed in the Penglaitan Section, Guangxi Province, South China, and related to the first appearance of the conodont subspecies Clarkina postbitteri postbitteri.[2]
Wuchiapingian life[]
Fossilized teeth of Janassa bituminosa
Glikmanius
Fadenia
It took reef ecosystems about 2.5 million years to recover from the Capitanian mass extinction.[3] Despite a marked decline in biodiversity, major groups of animals have survived. Brachiopods (Spiriferina, Neospirifer, Cancrinella, Lingula), bivalves (Nuculopsis, Polidevcia, Schizodus, Pseudomonotis), gastropods (Warthia, Euphemites, Babylonites, Mourlonia) and ammonites (Pseudogastrioceras, Altudoceras, Paraceltites, Konglingites, Jinjiangoceras) have been found in marine sediments of this age. Trilobites also lived in the seas, although their fossils of this age are rare. Pseudophillipsia is known from Guangxi, China, while Microphillipsia has been found in Wuchiapingian strata of Tabeno Mountain, Indonesia. Eurypterids also survived, although their most recent species was found in younger sediments. Ostracods were still common in both oceanic and freshwater ecosystems. Ozarkodinid conodonts, especially the genus Clarkina, survived the extinction and remained numerous. One subspecies of Clarkina from Wujiaping Formation of Sichuan, China, is used as a marker of lower boundary of this stage. Cartilaginous fishes remained the dominant group of vertebrates in Wuchiapingian seas. Petalodontiforms (Janassa), copodontiforms (Copodus), helodontiforms (Helodus), chimaeriforms (Arctacanthus), ctenacanthiforms (Glikmanius, Acondylacanthus) and various eugeneodontiforms (Agassizodus, Fadenia, Helicampodus, Parahelicampodus) hunted in the Panthalassa. Various osteichthyans (bony fishes) including elonichthyiforms (Varialepis, Strelnia), eurynotoidiforms (Isadia) and scanilepiforms (Toyemia) have been found in lacustrine sediments of East European platform.
The vast areas of Pangea had a hot and dry climate. A variety of terrestrial arthropods, including scorpions and myriapods, were able to adapt to the new conditions. Insects survived the extinction and probably already became the largest group of arthropods, if not all animals. Wuchiapingian insects include snakeflies (Raphisialis, Nanosialis, Lydasialis, Hymega), scorpionflies (Agetopanorpa, Neudolbenus, Tatarakara, Permeca), stoneflies (Boreoperlidium, Mirumoperla, Kargaloperla, Votaknemoura), orthopterans (Archifergania, Suchonoedischia, Vologdoptera, Monstrotitan), eoblattids (Mesoidelia, Parastenaropodites, Poldarsia, Megakhosarodes) and many other groups. Beetles (coleopterans) were the best adapted to dry climate and heat, since a strong chitinous carapace prevented the evaporation of water from the body. Several coleopteran genera (Schizocoleus, Protocupoides, Uskatocoleus, Tetracoleus) as well as all of the above insects were found in the Wuchiapingian sediments of Vologda, western Russia.
Important changes occurred among continental vertebrates. Various amphibians still lived in rivers and lakes, but the recent extinction had a severe impact on their diversity. As a result of the drying up of water bodies, some groups gradually died out. Seroherpeton is the last known embolomere; Diplocaulus minimus from Ikakern Formation of Morocco is the last known nectridean amphibian in Earth history. Temnospondyls continued to live in various regions of Pangea. Dvinosaurus were found in abundance in western Russia, where, apparently, vast fresh lakes remained in place of the sea bay of the previous Cisuralian and Guadalupian epochs. Rhinesuchid temnospondyls (Rhinesuchus, Rhinesuchoides, Laccosaurus) inhabited water bodies mainly in southern Africa. Several semi-aquatic tetrapods like Chroniosaurus have developed thick skin to reduce moisture evaporation. Such animals resembled crocodiles and led a similar lifestyle. Diadectomorphs, the possible relatives of amniotes, have almost extinct. The youngest diadectomorph, Alveusdectes, was found in Wuchiapingian Shangshihezi Formation in China. Seymouriamorphs like Microphon and Karpinskiosaurus continued to make attempts to adapt to life on land, but, most likely, during this age the number of these amphibians was greatly reduced.
Reptiles have become better adapted to high temperatures. Captorhinids (Captorhinus), and parareptiles (Kinelia) are known from this stage. Pareiasaurs (Arganaceras, Pareiasaurus, Pareiasuchus, Anthodon, Scutosaurus) were heavily armored and may have been the first large land reptiles. Procolophonids, another group of parareptiles, appeared in this age. Suchonosaurus, one of the oldest members, was found in Salarevskaya Formation in western Russia. Some reptiles learned to float in the air at this time. Reptiles like Coelurosauravus, Weigeltisaurus and Glaurung had wings consisting of elongated ribs with a membrane. In flight, they could hunt insects more efficiently. Archosauromorphs, the ancestors of crocodiles, dinosaurs and pterosaurs, gradually spread across the mainland. Protorosaurus, an archosauromorph from Wuchiapingian of Europe, had a long neck that allowed him to hunt fish or pull his victims out of holes.
Synapsids remained the dominant group, but they are very different from their more ancient relatives. Dinocephalians, characteristic of the previous epoch, almost completely died out. Their last possible members known from the Wuchiapingian stage are Microurania, Dinophoneus and Jonkeria. Mostly small forms survived. Dicynodonts became the most common herbivorous animals. Wuchiapingian dicynodonts include Dicynodon, Endothiodon, Diictodon, Oudenodon, Cistecephalus and many other genera. Many of them had elongated fangs, with which they dug up plant roots and defended themselves from predators. Gorgonopsians have become the new dominant land carnivores. Like predatory dinocephalians, they are characterized by saber teeth. Wuchiapingian gorgonopsians include Aelurognathus, Arctops, Sauroctonus, Rubidgea and such iconic members as Gorgonops, Lycaenops and the largest known genus, Inostrancevia. Therocephalians like Icticephalus, Ictidosuchoides and Hofmeyria were smaller, but also dangerous predators with long teeth. One genus, Euchambersia, may have had a venomous bite, although not all researchers share this view. Finally, cynodonts, the direct ancestors of mammals, survived and apparently spread throughout Pangea. Wuchiapingian genera include Procynosuchus, Nshimbodon, Cynosaurus, Charassognathus and Abdalodon.
References[]
- ↑ "Latest version of international chronostratigraphic chart". International Commission on Stratigraphy. https://stratigraphy.org/chart#latest-version.
- ↑ "GSSP Table - Paleozoic Era". https://timescalefoundation.org/gssp/index.php?parentid=77.
- ↑ Huang, Yuangeng; Chen, Zhong-Qiang; Zhao, Laishi; Stanley Jr., George D.; Yan, Jiaxin; Pei, Yu; Yang, Wanrong; Huang, Junhua (1 April 2019). "Restoration of reef ecosystems following the Guadalupian–Lopingian boundary mass extinction: Evidence from the Laibin area, South China". Palaeogeography, Palaeoclimatology, Palaeoecology. 519: 8–22. https://doi.org/10.1016/j.palaeo.2017.08.027