The Yanliao Biota is the name given to an assembly of fossils preserved in northeastern China from the Middle to

Late Jurassic The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...

.Xu, X., Zhou, Z., Sullivan, C. and Wang, Y., 2017. The Yanliao Biota: a trove of exceptionally preserved Middle-Late Jurassic terrestrial life forms. Terrestrial Conservation Lagerstätten. Dunedin Academic Press, London, pp.131-167. It includes fossils from the

Tiaojishan Formation The Tiaojishan Formation is a geological formation in Hebei and Liaoning, People's Republic of China, dating to the middle-late Jurassic period (Bathonian-Oxfordian (stage), Oxfordian stages). It is known for its Lagerstätte, exceptionally preser ...

and Haifanggou Formation. This spans approximately 165 to 150 million years ago. Like the Jehol Biota, these deposits are composed of alternating layers of volcanic tuff and sediment, and are considered

Lagerstätte A Fossil-Lagerstätte (, from ''Lager'' 'storage, lair' '' Stätte'' 'place'; plural ''Lagerstätten'') is a sedimentary deposit that preserves an exceptionally high amount of palaeontological information. ''Konzentrat-Lagerstätten'' preserv ...

. These are some of the best preserved Jurassic fossils in the world, and include many important dinosaur, mammal, salamander, insect and lizard specimens, as well as plants.

History

The first fossils of the Yanliao Biota were found around 1998 near the village of Daohugou in Inner Mongolia. The following year, the first two important specimens were discovered, and published in 2000. Since that time many more have been found from the same area, and in neighbouring provinces. The Yanliao Biota is made up of fossils from more than one locality, and the geology has been difficult to interpret (see below). It includes what was previously referred to as the Daohugou Biota,Sullivan C, Wang Y, Hone DWE, Wang Y, Xu X & Zhang F. 2014. The vertebrates of the Jurassic Daohugou Biota of northeastern China. ''Journal of Vertebrate Paleontology'', 34:2, 243-280, DOI: 10.1080/02724634.2013.787316 and some of it was thought to belong to the Jehol Biota.

Location

The Yanliao Biota comes from outcrops north of the Han Mountains, in the northeast of the

People's Republic of 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 ...

. The most important site is near Daohugou Village in Inner Mongolia, but fossils and outcrops are also found in neighbouring

Liaoning Province ) , image_skyline = , image_alt = , image_caption = Clockwise: Mukden Palace in Shenyang, Xinghai Square in Dalian, Dalian coast, Yalu River at Dandong , image_map = Liaoning in China (+all claims hatched).svg , ...

and Heibei Province.

Geology

The Dauhugou locality lies in the Ningchen Basin in the SE corner of

Inner Mongolia Inner Mongolia, officially the Inner Mongolia Autonomous Region, is an Autonomous regions of China, autonomous region of China. Its border includes two-thirds of the length of China's China–Mongolia border, border with the country of Mongolia. ...

. Dauhugou village has fossil-bearing lacustrine (laid down in lakes) strata overlying

precambrian The Precambrian ( ; or pre-Cambrian, sometimes abbreviated pC, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of t ...

basement.

Fossil preservation

The formations that yield the fossils of the Yanliao Biota are known as ''

'', meaning that they have exceptionally good conditions for fossil preservation. The fossils are not only numerous, but also very well preserved. For vertebrates, there are often whole skeletons with soft tissues like skin and fur, colour patterns, and stomach contents. Insects are intact with wings and patterns preserved, and plants have their leaves and flowers still attached. The volcanic ash layers quickly buried the organisms, and created an

anoxic Anoxia means a total depletion in the level of oxygen, an extreme form of hypoxia or "low oxygen". The terms anoxia and hypoxia are used in various contexts: * Anoxic waters, sea water, fresh water or groundwater that are depleted of dissolved ox ...

environment around them, preventing scavenging and helping preserve them.

Fossils

Dinosaurs

* ''

Anchiornis huxleyi ''Anchiornis'' is a genus of small, four-winged paravian dinosaurs, with only one known species, the type species ''Anchiornis huxleyi'', named for its similarity to modern birds. The Latin name ''Anchiornis'' derives from a Greek word meaning " ...

'' * '' Epidendrosaurus ningchengensis'' * ''

Epidexipteryx hui ''Epidexipteryx'' is a genus of small maniraptoran dinosaurs, known from one fossil specimen in the collection of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing. ''Epidexipteryx'' represents the earliest known example o ...

'' * '' Pedopenna daohugouensis'' * '' Xiaotingia zhengi'' * '' Aurornis xui'' * '' Eosinopteryx brevipenna'' * '' Caihong juji'' * '' Tianyulong confuciusi'' * '' Scansoriopteryx heilmanni'' * '' Yi qi'' * '' Serikornis sungei''

Pterosaurs

* '' Jeholopterus ningchengensis'' * '' Archaeoistiodactylus linglongtaensis'' (possibly '' Darwinopterus''; Martill and Etches, 2012) * '' Changchengopterus'' * ''

Darwinopterus modularis ''Darwinopterus'' (meaning "Darwin's wing") is a genus of pterosaur, discovered in China and named after biologist Charles Darwin. Between 30 and 40 fossil specimens have been identified, all collected from the Tiaojishan Formation, which dates t ...

'' * '' Darwinopterus linglongtaensis'' * '' Darwinopterus robustodens'' * '' Jianchangnathus robustus'' * '' Jianchangopterus zhaoianus'' * '' Fenghuangopterus lii'' * '' Kunpengopterus sinensis'' * '' Wukongopterus lii'' * '' Changchengopterus pani'' * '' Dendrorhynchoides mutoudengensis'' * '' Qinglongopterus guoi'' * '' Pterorhynchus wellnhoferi'' * '' Cascocauda rong'' * '' Sinomacrops bondei''

Mammaliaforms

* '' Castorocauda lutrasimilis'' * '' Volaticotherium antiquum'' * '' Arboroharamiya jenkinsi'' * '' Juramaia sinensis'' * '' Maiopatagium furculiferum'' * '' Vilevolodon diplomylos'' * '' Agilodocodon gracilis'' * '' Megaconus mammaliaformis'' * '' Docofossor brachydactylus'' * '' Microdocodon gracilis'' * ''

Rugosodon eurasiaticus ''Rugosodon'' is an extinct genus of multituberculate (rodent-like) mammals from eastern China that lived 160 million years ago during the Jurassic period. The discovery of its type species and currently only known species ''Rugosodon eurasiatic ...

'' * '' Mirusodens caii''

Caudates

* ''

Beiyanerpeton jianpingensis ''Beiyanerpeton'' is an extinct genus of salamandroid amphibians known from the Late Jurassic of western Liaoning Province, China. It contains a single species, ''B. jianpingensis''. Alternative analyses suggest that ''B. jianpingensis'' is a ste ...

'' * '' Chunerpeton tianyiensis'' * '' Jeholotriton paradoxus'' * '' Neimengtriton daohugouensis'' * '' Pangerpeton sinensis''

References

{{Reflist, 2 Geology of China Natural history of China Geography of Liaoning Geography of Hebei Geography of Inner Mongolia Geography of Northeast Asia Geologic formations of China Paleontology in Liaoning Paleontology in Hebei Mesozoic paleobiotas