Tiaojishan Formation
Geological formation in China
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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 stages). It is known for its exceptionally preserved fossils, including those of plants, insects and vertebrates. It is made up mainly of pyroclastic rock interspersed with basic volcanic and sedimentary rocks. Previously, the Tiaojishan Formation was grouped together with the underlying Haifanggou Formation (also known as the Jiulongshan Formation) as a single "Lanqi Formation."[1] The Tiaojishan Formation forms a key part of the Yanliao Biota assemblage, alongside the Haifanggou Formation.
| Tiaojishan Formation | |
|---|---|
| Stratigraphic range: Bathonian-Oxfordian ~ | |
Exposure of the Tiaojishan Formation at Nanshimenzi Village, Qinglong Manchu Autonomous County, Hebei Province, with red arrow pointing to fossiliferous beds | |
| Type | Geological formation |
| Underlies | Tuchengzi Formation, Houcheng Formation |
| Overlies | Haifanggou Formation |
| Thickness | 2,420 m (7,940 ft) |
| Lithology | |
| Primary | Andesite |
| Other | Sandstone, shale, tuff, coal |
| Location | |
| Coordinates | 41.3°N 119.2°E |
| Approximate paleocoordinates | 43.0°N 123.1°E |
| Region | Hebei, Inner Mongolia, & Liaoning |
| Country | China |
| Extent | Yanshan Belt |
  Tiaojishan Formation (China)  Tiaojishan Formation (Liaoning) | |
Age
Using Argon–argon dating, Wang and colleagues in 2005 dated part of the Tiaojishan Formation to about 160 million years ago, the beginning of the Oxfordian stage, the first stage of the Upper Jurassic epoch.[2] In 2006, a study by Liu and colleagues used U-Pb zircon dating to conclude that the Tiaojishan Formation correlates with the Daohugou Beds, and the complete chronological range of this shared biota dates to between 168 and 164/152 Ma ago.[3] A subsequent study, published in 2008, refined the age range of the formation further, finding that the lower boundary of the Tiaojishan was formed 165 Ma ago, and the upper boundary somewhere between 156 and 153 Ma ago.[4]
Climate
Based on the plant life present in the Tiaojishan Formation, Wang Yongdong and colleagues determined that the climate in Liaoning during the mid Jurassic would have been subtropical to temperate, warm and humid.[1]
Fauna
Beautifully preserved fossils of dinosaurs, pterosaurs, salamanders, insects, arachnids[5] and other invertebrates, conifers, ginkgoes, cycads, horsetails, and ferns, and even the earliest known gliding mammal (Volaticotherium) have been discovered in these rocks.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 trees.[6]
The forests of the Yanliao biota grew in a humid, warm - temperate climate and were dominated by gymnosperm trees. There were ginkgopsids 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.[7]
Fish
| Fish of the Tiaojishan Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Abundance | Notes | Images |
|
Y. occisor[8] |
Liaoning |
A lamprey. |
 | |||
Salamanders
| Salamanders of the Tiaojishan Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Abundance | Notes | Images |
|
B. jianpingensis[9] |
Liaoning |
 | ||||
|
C. tianyiensis |
||||||
|
J. paradoxus |
||||||
|
L. daohugouensis |
||||||
|
P. sinensis |
||||||
Pterosaurs
| Pterosaurs of the Tiaojishan Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Abundance | Notes | Images |
|
A. linglongtaensis[10] |
Liaoning |
A monofenestratan known from an incomplete skeleton with a partial skull and lower jaw |
     | |||
|
C. rong[11] |
Daohugou bed[12] |
One specimen |
A long-tailed batrachognathine anurognathid known from a complete skeleton with preserved impressions of soft-tissue | |||
|
C. pani[13] |
Hebei |
A pterodactyliform known only from a single specimen of a young juvenile, measuring 475 millimeters (18.7 in) in wingspan. | ||||
|
D. delicatus[14] |
One specimen |
Pterosaur known from a partial skeleton with soft tissue impressions | ||||
|
D. modularis[15] |
Liaoning |
|||||
|
D. linglongtaensis |
||||||
|
D. robustodens |
||||||
|
D. camposi[16] |
Liaoning | One specimen | ||||
|
D. curvidentatus? |
One specimen |
An anurognathid; originally reported from the Yixian Formation, later suggested to be from Tiaojishan;[17] other studies dispute this[18] | ||||
|
D. zhengi[19] |
Linglongta |
One specimen |
A non-pterodactyloid monofenestratan | |||
|
F. lii[20] |
Liaoning |
|||||
|
J. ninchengensis |
Inner Mongolia |
A batrachognathine anurognathid with preserved soft tissue anatomy | ||||
|
J. robustus[23] |
Liaoning |
A scaphognathine rhamphorhynchid known from a single fossil skeleton | ||||
|
J. zhaoianus[24] |
Liaoning |
A scaphognathine rhamphorhynchid known from a nearly complete skeleton with the skull preserved | ||||
|
K. sinensis[25] |
Liaoning |
Daohugou bed |
Three specimens |
A wukongopterid | ||
|
K. antipollicatus[26] |
Liaoning |
Two nearly complete specimens | ||||
|
L. primus[27] |
Daxishan (Linglongta) |
One specimen |
||||
|
Hebei |
One specimen |
A batrachognathine anurognathid; originally classed as a species of Dendrorhynchoides; suggested to have been Early Cretaceous in age | ||||
|
P. wellnhoferi |
Inner Mongolia |
Daohugou bed |
One specimen[21] |
A darwinopteran known from a nearly complete skeleton including preserved soft-tissue anatomy | ||
|
Q. guoi[29] |
Liaoning |
A rhamphorhynchine rhamphorhynchid known from only one specimen | ||||
|
S. bondei[12] |
Hebei |
Daohugou bed |
One specimen |
A long-tailed batrachognathine anurognathid known from a relatively complete skull and skeleton with soft tissue patches | ||
|
W. lii |
Liaoning |
Daohugou bed |
One specimen[30] |
A wukongopterid | ||
Dinosaurs
- Ornithischians
| Ornithischians of the Tiaojishan Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Abundance | Notes | Images |
|
P. qinglong |
Qinglong |
One specimen |
The first neornithischian described from the Yanliao Biota; known from a well-preserved, articulated, nearly complete skeleton including soft tissue impressions and gut contents. |
  | ||
|
T. confuciusi |
Liaoning |
A heterodontosaur initially reported as being from the Early Cretaceous Jehol group; preserved with feather-like filaments | ||||
- Theropods
| Theropods of the Tiaojishan Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Abundance | Notes | Images |
|
A. huxleyi[32] |
Several specimens[33] |
An anchiornithid at first believed to be a troodontid; analysis of the fossils has enabled scientists to determine what colors the animal may have exhibited in life |
          | |||
|
A. xui |
Liaoning |
One specimen |
An anchiornithid roughly the size of a modern pheasant | |||
|
C. juji |
Yanliao Biota |
One specimen |
An anchiornithid known from an adult specimen measuring 400 mm in body length; analysis of the fossils has enabled scientists to determine what colors the animal may have exhibited in life[34] | |||
|
E. brevipenna |
Liaoning |
One specimen |
An anchiornithid at first believed to be a troodontid, known from a single complete skeleton of a subadult or adult individual | |||
|
E. hui |
Daohugou beds |
One specimen |
A scansoriopterygid known from a well-preserved partial skeleton, measuring 10 inches in length (17.5 inches including the incomplete tail feathers) | |||
|
P. daohugouensis |
Inner Mongolia |
Daohugou beds |
One specimen |
An anchiornithid known only from a foot and ankle with soft tissue impressions | ||
|
S. heilmanni |
Liaoning |
Exact provenance of type specimen unknown, most likely from the Daohugou Beds[35] |
One or two specimens |
A sparrow-sized scansoriopterygid known from one or two juvenile specimens | ||
|
S. sungei |
Liaoning |
One specimen[36] |
An anchiornithid with plumulaceous-like feathers | |||
|
X. zhengi[37] |
Liaoning |
One specimen |
An anchiornithid originally thought to be either a dromaeosaur or a troodontid | |||
|
Y. qi[38] |
Daohugou beds |
One specimen |
A gliding scansoriopterygid, weighing about 380 grams (0.84 pounds) | |||
Lizards
Color key
|
Notes Uncertain or tentative taxa are in small text; |
| Lepidosaurs (lizards and relatives) of the Daohugou Beds | |||||
|---|---|---|---|---|---|
| Genus | Species | State | Abundance | Notes | Images |
|
Unnamed lizard[39] |
Inner Mongolia |
One specimen |
A new lizard with relatively short forelimbs |
||
|
Unnamed lizard[39] |
Inner Mongolia |
One specimen |
A lizard with long hind limbs and a narrow body |
||
Cynodonts
| Cynodonts of the Tiaojishan Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Abundance | Notes | Images |
|
A. scansorius |
Daohugou bed |
A shrew-sized, arboreal docodontid[40] |
      | |||
|
A. jenkinsi |
One specimen |
An arboreal, prehensile-tailed euharamiyid haramiyidan estimated to have weighed about 354 grams[41] | ||||
| A. fuscus | A preserved skeleton with fur | An arboreal, prehensile-tailed euharamiyid haramiyidan with a specific fur | ||||
|
D. brachydactylus |
One specimen[42] |
A docodontid specialized for a subterranean burrowing lifestyle | ||||
|
J. sinensis[43] |
Liaoning |
One specimen |
A small, shrew-like therian which weighed around 15–17 grams (0.53–0.60 oz); it may be a stem-eutherian,[43] but this classification has been questioned by some[44][45] | |||
| Maiopatagium | M. furculiferum | |||||
|
M. mammaliaformis |
Inner Mongolia |
Daohugou bed |
One specimen |
An eleutherodontid haramiyidan thought to have been a herbivore that lived on the ground[46] | ||
| Microdocodon | M. gracilis | Daohugou bed | A tegotheriid docodontan | |||
| Qishou | Q. jizantang | Euharamiyida | ||||
|
R. eurasiaticus |
Liaoning |
Daxishan site |
One specimen |
An omnivorous paulchoffatoid multituberculate; one of the oldest-known multituberculates[47] It is estimated to have weighed between 65 and 80 grams, about that of an average chipmunk. | ||
|
V. antiquum |
Inner Mongolia |
Daohugou bed |
One specimen |
A gliding, flying squirrel-like volaticotherian eutriconodont with a specialized gliding membrane | ||
| Vilevolodon | V. diplomylos | A gliding eleutherodontid haramiyidan | ||||
| Xianshou | X. linglong, X. songae | A gliding euharamiyidan | ||||
Arthropods
The following orders are represented in the formation; Ephemeroptera, Odonata, Plecoptera, Blattodea, Orthoptera, Hemiptera, Neuroptera, Coleoptera, Hymenoptera, and Diptera.
An indeterminate aeshnoid (insect) species is known from Liaoning.[32]
Color key
|
Notes Uncertain or tentative taxa are in small text; |
| Arthropods of the Daohugou Beds | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | State | Abundance | Notes | Images | |
|
Ahirmoneura |
A. neimengguensis[48] |
|||||
|
Archirhagio |
A. striatus[49] |
Archisargid flies | ||||
|
A. zhangi[50] |
Inner Mongolia |
|||||
|
Archisargus |
A. spurivenius[49] |
Archisargid flies | ||||
|
A. strigatus[49] |
||||||
|
Calosargus |
C. (Calosargus) antiquus[49] |
Archisargid flies | ||||
|
C. (C.) bellus[49] |
||||||
|
C. (C.) daohugouensis[49] |
||||||
|
C. (C.) hani[49] |
||||||
|
C. (C.) tenuicellulatus[49] |
||||||
|
C. (C.) validus[49] |
||||||
|
C. (Pterosargus) sinicus[49] |
Inner Mongolia |
|||||
|
D. impudica[32] |
Liaoning |
An ostracod | ||||
|
D. magna[32] |
Liaoning |
An ostracod | ||||
|
D. sarytirmenensis[32] |
Liaoning |
An ostracod | ||||
|
Daohugocorixa |
D. vulcanica[49] |
|||||
|
Fuyous |
F. gregarious[49] |
A mayfly | ||||
|
E. gertschi[51] |
1 Specimen |
A plectreurid spider | ||||
|
Homocatabrycus |
H. liui[52] |
A schizophorid flying water beetle | ||||
|
Jurassinemestrinus |
J. orientalis[49] |
Inner Mongolia |
A Nemestrinoid fly | |||
|
Menopraesagus |
M. explanatus[52] |
Schizophorid flying water beetles | ||||
|
M. oxycerus[52] |
||||||
|
M. grammicus[52] |
||||||
|
Meoslova |
M. daohugouensis[49] |
An archisargid fly | ||||
|
Mostovskisargus |
M. portentosus[49] |
Inner Mongolia |
Archisargid flies | |||
|
M. signatus[49] |
Inner Mongolia |
|||||
|
Shantous |
S. lacustris[49] |
A mayfly | ||||
|
Sinoschizala |
S. darani[52] |
A schizophorid flying water beetle | ||||
Other invertebrates
Flora
Survey based on Wang et al. 2006 unless otherwise noted.[1]
Bennettitales
Cycad-like plants, the most abundant plant group in the formation. 27 species in 11 genera.
| Bennettitales of the Tiaojishan Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Abundance | Notes | Images |
|
Anomozamites |
||||||
|
Bennetticarpus |
||||||
|
Cycadolepis |
||||||
|
Jacutiella |
||||||
|
Pteriophyllum |
||||||
|
Williamsoniella |
||||||
|
Zamiophyllum |
||||||
Ginkgoales
Prehistoric ginkgo trees, common, with 11 species present in 6 genera.
| Ginkgoales of the Tiaojishan Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Abundance | Notes | Images |
|
Ixostrobus |
||||||
|
Phoenicopsis |
||||||
|
Solenites |
||||||
Pinophyta
Conifers, 5 species present in 4 genera.
| Pinophytans of the Tiaojishan Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Abundance | Notes | Images |
|
Pityocladus |
||||||
|
Pityophyllum |
||||||
|
Podizamites |
||||||
|
Schizolepis |
||||||
|
Yuccites |
||||||
Pteridophyta
Leptosporangiate ferns, represented by 17 species in 8 genera, are the second most abundant plant type in the formation.
| Pteridophytans of the Tiaojishan Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Abundance | Notes | Images |
| Ashicaulis | Beipiao | One specimen | A whole-plant osmundacean. Preserved stem 50 cm high and 35–41 cm across. Sterile fronds of Cladophlebis-type, fertile fronds of Todites-type with in-situ spores of Osmundacidites-type.[53] | |||
|
Form genus of sterile fern fronds, typically assigned to Osmundaceae. A whole-plant osmundacean tree-fern with Cladophlebis fronds attached is known from this formation. | ||||||
| Claytosmunda | C. chengii, C. liaoningensis, C. plumites, C. preosmunda, C. sinica, C. wangii | Beipiao, Liaoning | Numerous specimens | Interrupted ferns. Numerous fossil rhizomes previously assigned to Millerocaulis or Ashicaulis were interpreted to be close relatives and possible precursors of Claytosmunda claytoniana, the only extant representative of the genus.[54] | ||
| Dicksonia | D. changeyingziensis | Dicksoniaceae Tree ferns. | ||||
| D. charielsa | ||||||
| Eboracia | Dicksoniaceae Tree ferns. | |||||
|
Hausmannia |
H. shebudaiensis |
Uncommon. |
||||
|
M. hoerenensis |
Uncommon. |
A marattiopsid fern. | ||||
|
Raphaelia |
R. stricta |
A fern. | ||||
|
Todites |
T. denticulata | Fertile fronds of osmundacean ferns that resemble Todea. Known to attach to "Ashicaulis"-type stems with sterile Cladophlebis-type fronds in this formation. | ||||
| T. williamsonii | Isolated fertile fronds of osmundacean ferns resembling Todea. | |||||
Other plants
Cycads, fairly diverse, with 10 species present in 2 genera.
| Cycads of the Tiaojishan Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Abundance | Notes | Images |
|
Hepacitities |
H. shebudaiensis |
Uncommon. |
A bryophyte. | |||
|
Taeniopteris sp. |
Uncommon. |
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