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The Daohugou Beds are a series of fossil-bearing rock deposits located in northeastern China
China

China is a Culture of China, an ancient civilization, and, depending on perspective, a national or multinational entity extending over a large area in East Asia....
, south of Chifeng
Chifeng

Chifeng is a prefecture-level city in southeastern Inner Mongolia Autonomous Region. It borders Xilin Gol League to the north and west, Tongliao to the northeast, and Chaoyang, Liaoning prefecture of Liaoning and Chengde prefecture of Hebei to the south....
, around Daohugou village of Ningcheng county. The rocks are grey, finely bedded, lacustrine, sandy mudstones mixed with tuffaceous mudstones. The beds probably date from between the late Middle Jurassic
Middle Jurassic

The Middle Jurassic, called the Dogger in the European system of classification, is the second epoch of the Jurassic Period . It lasted from 176-161 million years ago....
 (168 million years ago) and early Late Jurassic
Late Jurassic

The Late Jurassic Epoch of the Jurassic Period is the unit of geologic time scale from 161.2 ? 4.0 to 145.5 ? 4.0 million years ago, which is preserved in Upper Jurassic stratum....
 Period (164-152 million years ago).

geology of the Daohugou Beds is confusing because it is complex and does not conform; meaning that elements and layers of rock of different ages are mixed up together by folding and by volcanic activity.






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The Daohugou Beds are a series of fossil-bearing rock deposits located in northeastern China
China

China is a Culture of China, an ancient civilization, and, depending on perspective, a national or multinational entity extending over a large area in East Asia....
, south of Chifeng
Chifeng

Chifeng is a prefecture-level city in southeastern Inner Mongolia Autonomous Region. It borders Xilin Gol League to the north and west, Tongliao to the northeast, and Chaoyang, Liaoning prefecture of Liaoning and Chengde prefecture of Hebei to the south....
, around Daohugou village of Ningcheng county. The rocks are grey, finely bedded, lacustrine, sandy mudstones mixed with tuffaceous mudstones. The beds probably date from between the late Middle Jurassic
Middle Jurassic

The Middle Jurassic, called the Dogger in the European system of classification, is the second epoch of the Jurassic Period . It lasted from 176-161 million years ago....
 (168 million years ago) and early Late Jurassic
Late Jurassic

The Late Jurassic Epoch of the Jurassic Period is the unit of geologic time scale from 161.2 ? 4.0 to 145.5 ? 4.0 million years ago, which is preserved in Upper Jurassic stratum....
 Period (164-152 million years ago).

Geology

The geology of the Daohugou Beds is confusing because it is complex and does not conform; meaning that elements and layers of rock of different ages are mixed up together by folding and by volcanic activity. Liu et al. (2006) concluded that the rocks that bear the Daohugou Biota include the Tiaojishan, Lanqi, and Daohugou formations. They demonstrated that the Jiulongshan Formation is older (Middle Jurassic
Middle Jurassic

The Middle Jurassic, called the Dogger in the European system of classification, is the second epoch of the Jurassic Period . It lasted from 176-161 million years ago....
), and that the Tuchengzi Formation
Tuchengzi Formation

The is a geological Formation in China whose strata date back to the Late Jurassic. Dinosaur remains are among the fossils that have been recovered from the formation....
 is younger (Late Jurassic
Late Jurassic

The Late Jurassic Epoch of the Jurassic Period is the unit of geologic time scale from 161.2 ? 4.0 to 145.5 ? 4.0 million years ago, which is preserved in Upper Jurassic stratum....
).

Fieldwork published in 2006 has also found that the beds are consistent over a large area; from western Liaoning
Liaoning

is a Northeast China political divisions of China of the People's Republic of China. Its one-Chinese character abbreviation is Liao ."Li?o" is an ancient name for this region, which was adopted by the Liao Dynasty which ruled this area between 907 and 1125....
 into Ningcheng county of Inner Mongolia
Inner Mongolia

Inner Mongolia is the Mongols autonomous region of China of the People's Republic of China, located in the country's north.Inner Mongolia borders, from east to west, the provinces of Heilongjiang, Jilin, Liaoning, Hebei, Shanxi, Shaanxi, Ningxia, and Gansu, while to the north it borders Mongolia and Russia....
 (Nei Mongol). The age of the Daohugou Beds has been debated, and a number of studies, using different methodology, have reached conflicting conclusions. Various papers have placed the fossils here as being anywhere from the Middle Jurassic
Middle Jurassic

The Middle Jurassic, called the Dogger in the European system of classification, is the second epoch of the Jurassic Period . It lasted from 176-161 million years ago....
 period (169 million years ago) to the Early Cretaceous
Early Cretaceous

The Early Cretaceous or the Lower Cretaceous , is the earlier of the two major divisions of the Cretaceous Period . It began about 146 million years ago....
 period (122 ma) .

Scientific Studies

A 2004 study by He et al. on the age of the Daohugou Beds found them to be Early Cretaceous, probably only a few million years older than the overlying Jehol beds of the Yixian Formation
Yixian Formation

The Yixian Formation is a geological formation in Jinzhou, Liaoning, People's Republic of China, that stems from the early Cretaceous period. It is known for its fossils....
. The 2004 study primarily used radiometric dating
Radiometric dating

Radiometric dating is a technique used to date materials, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates....
 of a tuff
Tuff

Tuff is a type of Rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption. Tuff is also sometimes called tufa, particularly when used as construction material....
 within the Daohugou Beds to determine its age. However, a subsequent study by Gao & Ren took issue with the He et al. study. Gao and Ren criticize He et al. for not including enough specifics and detail in their paper, and also take issue with their radiometric dating of the Daohugou tuff. The tuff, Gao and Ren argue, contains crystals with a variety of diverse radiometric ages, some up to a billion years old, so using dates from only a few of these crystals cannot determine the overall age of the deposits. Gao and Ren go on to defend a Middle Jurassic age for the beds based on biostratigraphy
Biostratigraphy

Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock Stratum by using the fossil assemblages contained within them....
 (the use of index fossil
Index fossil

Index fossils are fossils used to define and identify geologic columns . They work on the premise that, although different sediments may look different depending on the conditions under which they were laid down, they may include the remains of the same species of fossil....
s) and the bed's relationship to a layer that is known to mark the Middle Jurassic-Late Jurassic boundary.

Another study, published in 2006 by Wang et al., found that the Tiaojishan Formation (159-164 million years old, Middle
Middle Jurassic

The Middle Jurassic, called the Dogger in the European system of classification, is the second epoch of the Jurassic Period . It lasted from 176-161 million years ago....
-early Late Jurassic
Late Jurassic

The Late Jurassic Epoch of the Jurassic Period is the unit of geologic time scale from 161.2 ? 4.0 to 145.5 ? 4.0 million years ago, which is preserved in Upper Jurassic stratum....
 in age) underlies, rather than overlies, the Daohugou Beds. Unlike the earlier study by Gao and Ren, Wang et al. found an overall similarity between the fossil animals found in the Daohugou Beds and those from the Yixian Formation. The authors stated that
"vertebrate fossils such as Liaoxitriton, Jeholopterus and feathered maniraptorans show much resemblance to those of the Yixian Formation. In other words, despite the absence of Lycoptera, a typical fish of the Jehol Biota, the Daohugou vertebrate assemblage is closer to that of the Early Cretaceous Jehol Biota than to any other biota."
Wang et al. concluded that the Daohugou probably represents the earliest evolutionary stages of the Jehol Biota
Jehol Biota

The Jehol Biota includes all the living organisms - the ecosystem - of northeastern China between 133 to 120 million years ago. This is the Lower Cretaceous ecosystem which left fossils in the Yixian Formation and Jiufotang Formation....
, and that it "belongs to the same cycle of volcanism and sedimentation as the Yixian Formation of the Jehol Group." Later in 2006, Liu et al. published their own study of the age of the Daohugou beds, this time using Zircon U-Pb dating on the volcanic rocks overlying and underlying salamander-bearing layers (salamanders are often used as index fossils). Liu et al. found that the beds formed between 164-158 million years ago, in the Middle to Late Jurassic.

Fauna of the Daohugou Beds

Beautifully preserved fossils of dinosaur
Dinosaur

Dinosaurs were the dominant vertebrate animals of Landform ecosystems for over 160 million years, from the late Triassic Period until the end of the Cretaceous Period , when most of them became extinct in the Cretaceous?Tertiary extinction event....
s, pterosaur
Pterosaur

Pterosaurs were flying reptiles of the clade or Order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight....
s, salamander
Salamander

Salamander is a common name of approximately 500 species of amphibians. They are typically characterized by slender bodies, short noses, and long tails....
s, insect
Insect

Insects are the biggest class of arthropods and the only ones with wings. They are the most diverse group of animals on the planet. They are most diverse at the equator and their diversity declines toward the poles....
s, other invertebrate
Invertebrate

An invertebrate is an animal lacking a vertebral column. The group includes 98% of all animal species ? all animals except those in the Chordate subphylum vertebrate ....
s, conifers, ginkgo
Ginkgo

Ginkgo , frequently misspelled as "Gingko", and also known as the Maidenhair Tree after Adiantum, is a unique species of tree with no close living relatives....
es, cycad
Cycad

File:Cycad cone.jpgCycads are a group of seed plants characterized by a large crown of compound Leaf and a stout trunk . They are evergreen, gymnospermous, dioecious plants having large pinnately compound leaves....
s, horsetail
Horsetail

Equisetum is the only living genus in the Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds. They are commonly known as horsetails....
s, and fern
Fern

A fern is any one of a group of about 20,000 species of plants classified in the phylum or division Pteridophyta, also known as Filicophyta....
s, and even the earliest known gliding mammal (Volaticotherium) and an aquatic protomammal (Castorocauda) have been discovered in these rocks. These organisms were part of the of the Daohugou Biota, which was the ecosystem of that Jurassic time. The tuffaceous composition of some rock layers show that this was a volcanic area, occasionally experiencing heavy ashfalls from eruptions. The landscape then was dominated by mountain streams and deep lakes surrounded by forests of gymnosperm
Gymnosperm

Gymnosperm is a group of spermatophyte seed-bearing plants with ovules on scales, which are usually arranged in cone-like structures. The other major group of seed-bearing plants, the angiosperms, [from the Greek, 'angion' - container] have ovules enclosed in a carpel, a sporophyll with fused margins....
 trees. Some authors have concluded that the Daohugou Biota is an early stage of the Jehol Biota
Jehol Biota

The Jehol Biota includes all the living organisms - the ecosystem - of northeastern China between 133 to 120 million years ago. This is the Lower Cretaceous ecosystem which left fossils in the Yixian Formation and Jiufotang Formation....
, while recent work has demonstrated that the two are distinct.

The forests of the Daohugou biota grew in a humid, warm - temperate climate and were dominated by gymnosperm
Gymnosperm

Gymnosperm is a group of spermatophyte seed-bearing plants with ovules on scales, which are usually arranged in cone-like structures. The other major group of seed-bearing plants, the angiosperms, [from the Greek, 'angion' - container] have ovules enclosed in a carpel, a sporophyll with fused margins....
 trees. There were ginkgo
Ginkgo

Ginkgo , frequently misspelled as "Gingko", and also known as the Maidenhair Tree after Adiantum, is a unique species of tree with no close living relatives....
psids like Ginkoites, Ginkgo, Baiera, Czekanowskia, and Phoenicopsis. There were also conifers like Pityophyllum, Rhipidiocladus, Elatocladus, Schizolepis, and Podozamites. Also, Lycopsids like Lycopodites and Sellaginellities, horsetails (Sphenopsida) like Equisetum, cycads like Anomozamites, and ferns (Filicopsida) like Todites and Coniopteris.

Amphibians

Amphibian
Amphibian

Amphibians , such as frogs, toads, salamanders, newts and caecilians, are cold-blooded animals that metamorphose from a juvenile, water-breathing form to an adult, air-breathing form....
s of the Daohugou Beds
Taxa Presence Description Images
Genus:* Liaoxitriton daohugouensis  A salamander.


Birds and other theropods

Theropod dinosaur
Dinosaur

Dinosaurs were the dominant vertebrate animals of Landform ecosystems for over 160 million years, from the late Triassic Period until the end of the Cretaceous Period , when most of them became extinct in the Cretaceous?Tertiary extinction event....
s of the Daohugou Beds
Taxa Presence Description Images
Genus:* Epidendrosaurus ninchengensis  A scansoriopterygid
Scansoriopterygidae

Scansoriopterygidae is a family of maniraptoran dinosaurs known from well-preserved fossils uncovered in Liaoning, China.Scansoriopteryx and Epidendrosaurus were the first non-avian dinosaurs found that had clear adaptations to an arboreal or semi-arboreal lifestyle--it is likely that they spent much of their time in trees....
.
Genus:* Epidexipteryx hui  A scansoriopterygid
Scansoriopterygidae

Scansoriopterygidae is a family of maniraptoran dinosaurs known from well-preserved fossils uncovered in Liaoning, China.Scansoriopteryx and Epidendrosaurus were the first non-avian dinosaurs found that had clear adaptations to an arboreal or semi-arboreal lifestyle--it is likely that they spent much of their time in trees....
.
Genus:* Jinfengopteryx elegans  A troodontid.
Genus:* Pedopenna daohugouensis  A primitive paravian
Paraves

Paraves is a stem?based clade containing birds and other closely related dinosaurs. The paravians include the Avialae, such as Archaeopteryx, and the Deinonychosauria, which includes the dromaeosaurids and troodontids....
.


Insects

Theropod dinosaur
Dinosaur

Dinosaurs were the dominant vertebrate animals of Landform ecosystems for over 160 million years, from the late Triassic Period until the end of the Cretaceous Period , when most of them became extinct in the Cretaceous?Tertiary extinction event....
s of the Daohugou Beds
Taxa Presence Description Images
Genus:* Mesoneta  
  • Ephemeroptera
  
  • Odonata
    Odonata

    Odonata is an Order of insects, encompassing Dragonfly and Damselfly . The word dragonfly is also sometimes used to refer to all Odonata. The term odonate has been coined to provide an English language name for the group as a whole, but is not in common usage; most Odonata enthusiasts avoid ambiguity by using the term true dragon...
    		•   
  • Plecoptera
    Plecoptera

    Plecoptera are an order of insects, commonly known as stoneflies. There are some 1,700 recorded species worldwide, and new ones are still being discovered....
    		•   
  • Blattodea
    		•   
  • Orthoptera
    Orthoptera

    The Orthoptera are an order of insects with paurometabolous or incomplete metamorphosis, including the grasshoppers, cricket s and locusts. Many insects in this order produce sound by rubbing their wings against each other or their legs, the wings or legs containing rows of corrugated bumps....
    		•   
  • Heteroptera
    Heteroptera

    Heteroptera is a group of about 40,000 species of insects in the Hemiptera. Sometimes called "true bugs", that name more commonly refers to Hemiptera as a whole, and "typical bugs" might be used as a more unequivocal alternative since among the Hemiptera the heteropterans are most consistently and universally termed "bugs"....
    		•   
  • Homoptera
    		•   
  • Neuroptera
    Neuroptera

    The insect order Neuroptera, or net-winged insects, includes the lacewings, Mantispidae, antlions, and their relatives. The order contains some 4,000 species....
    		•   
  • Coleoptera
    		•   
  • Hymenoptera
    Hymenoptera

    Hymenoptera is one of the larger order s of insects, comprising the sawfly, wasps, bees, and ants. The name refers to the membranous wings of the insects, and is derived from the Ancient Greek language wikt:???? : membrane and wikt:pte??? : wing....
    		•   
  • Diptera
    		•   


    Mammals and relatives

    Mammaliaformes
    Mammaliaformes

    Mammaliaformes is a clade that contains the mammals and their closest Extinction relatives. The precise Phylogenetics is disputed due to the scantness of evidence in the fossil record....
     and true mammal
    Mammal

    Mammals are a class of vertebrate animals whose name is derived from their distinctive feature, mammary glands, with which they feed their young....
    s of the Daohugou Beds
    Taxa Presence Description Images
    Genus:* Castorocauda lutrasimilis
    Castorocauda lutrasimilis

    Castorocauda lutrasimilis is the name given to a small, semi-aquatic relative of mammals living in the middle Jurassic period, 164 million years ago, in lakebed sediments of the Daohugou Beds of Inner Mongolia....
    		  A aquatic docodont.
    Genus:* Volaticotherium antiquum
    Volaticotherium antiquum

    Volaticotherium antiquum was an ancient gliding mammal not closely related to any other mammalian group currently known. It had a gliding membrane similar to a modern-day flying squirrel....
    		  An early gliding mammal.


    Pterosaurs

    Pterosaur
    Pterosaur

    Pterosaurs were flying reptiles of the clade or Order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight....
    s of the Daohugou Beds
    Taxa Presence Description Images
    Genus:* Jeholopterus ninchengensis  An anurognathid
    Anurognathid

    Anurognathids were a group of small pterosaurs, mostly tailess, that lived worldwide during the Jurassic Period. Some examples are Anurognathus and Batrachognathus....
    .
    Genus:* Pterorhynchus wellnhoferi  A rhamphorhynchid with unusual
    soft tissue ornamentation.


    See also

    • Yixian Formation
      Yixian Formation

      The Yixian Formation is a geological formation in Jinzhou, Liaoning, People's Republic of China, that stems from the early Cretaceous period. It is known for its fossils....
    • Jehol Biota
      Jehol Biota

      The Jehol Biota includes all the living organisms - the ecosystem - of northeastern China between 133 to 120 million years ago. This is the Lower Cretaceous ecosystem which left fossils in the Yixian Formation and Jiufotang Formation....
    • List of fossil sites
      List of fossil sites

      This is a worldwide list of important and/or well-known localities where fossils have been found. Such locations may either be a geological formation or a single site....
       (with link directory)