Article · Wikipedia archive · Last revised Aug 7, 2026

Kaili Formation

The Kaili Formation is a stratigraphic formation which was deposited during the Lower and Middle Cambrian. The formation is approximately 200 metres (660 ft) thick and was named after the city Kaili in the Guizhou province of southwest China.

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Kaili Formation
Stratigraphic range: Cambrian
TypeGeological formation
Thickness~200 m (660 ft)
Lithology
PrimaryClaystone, mudstone, shale
OtherSiltstone, marl, limestone
Location
Coordinates24°54′N 102°30′E / 24.9°N 102.5°E / 24.9; 102.5
Approximate paleocoordinates35°06′N 161°18′E / 35.1°N 161.3°E / 35.1; 161.3
RegionGuizhou
CountryChina
Type section
Named forKaili
Kaili Formation (China)
Show map of China
Kaili Formation (Guizhou)
Show map of Guizhou

The Kaili Formation (simplified Chinese: 凯里组; traditional Chinese: 凱里組; pinyin: Kǎilǐ zǔ) is a stratigraphic formation which was deposited during the Lower and Middle Cambrian (~513 to 506 million years ago). The formation is approximately 200 metres (660 ft) thick and was named after the city Kaili in the Guizhou province of southwest China.

The depositional environment of the Kaili Formation is not entirely known, and there are two hypotheses for its formation. It may have been a nearshore marine environment with 'normal' levels of oxygenation; or it may have been a deeper water environment further from the shore, on the open continental shelf; in this setting oxygen would not be available below the surface layers of the deposited sediment.1 The trace fossil assemblages in the formation suggest that it was below the wave base and was reasonably well-oxygenated.1

Fossils

The faunal assemblage is highly diverse, comprising some 110 genera among 11 phyla; of these, some 40 genera are also found in the Burgess Shale, and some 30 are also found in the Maotianshan Shale. Trilobites and eocrinoids with hard parts that are easily preserved are the most common fossils, but many animals with only soft tissues are also preserved. For example, the arthropod Skania similar to the Ediacaran Parvancorina of the Neoproterozoic age Ediacara Hills of South Australia has been found at the Kaili site.2

The middle part of the Kaili Formation, the Oryctocephalus indicus Zone, contains a Burgess Shale-type Lagerstätte with many well-preserved fossils known collectively as the Kaili Biota. In terms of age, this biota is located between the two most important and famous Cambrian Lagerstätten: the middle Lower Cambrian Maotianshan Shale (containing the Chengjiang Biota), also from China: and the Middle Cambrian Burgess Shale, known from Canada.34

Some other notable fossils discovered at Kaili are putative invertebrate eggs and embryos,5 trace fossils of the genus Gordia (not to be confused with the Gordian worms),1 as well as Naraoia, chancellorids, Microdictyon, Wiwaxia, and Marrella.4 Furthermore, the possible moss Parafunaria is also known, marking the earliest likely fossil of land plants.6 However this fossil has been disputed, as its Cambrian age means more conclusive proof is needed to determine whether it truly is a moss.7

The Kaili Formation is subdivided into three trilobite zones:

Paleobiota

Animals

Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
Animals
Genus Species Higher taxon Notes Images
Skania? "S." sundbergi2 Acercostraca Likely does not belong to the genus9
Carapace of "S." sundbergi source ↗
Olenoides O. paraptus Dorypygidae Preserved with gut contents10
Fossil of O. superbus from the Marjum Formation source ↗
Alicaris A. kailiensis11 Arthropoda
Pseudoarctolepis P. semicircularis Hymenocarina Differs from the type species in having smaller semicircular "wings"11
P. sharpii reconstruction source ↗
Tuzoia T. bispinosa Tuzoiidae Preserves ontogeny12
T. retifera life restoration source ↗
Forfexicaris F. reticulata Megacheira? Relatively similar to the type species11
Reconstruction of the type species F. valida source ↗
Leanchoilia L. sp Megacheira Preserves neuroanatomy13
Fuxianhuiida indet? Unapplicable Deuteropoda Known from a poorly preserved specimen with trilobite fragments inside its gut14
Mollisonia M. sinica Mollisoniida Differs from Burgess Shale specimens in the shape of the tail and head shields15
Reconstruction of M. plenovenatrix source ↗
Ursulinacaris U. cf. grallae Hurdiidae One of the first hurdiids from Miaolingian China16
source ↗
Ottoia O. guizhouensis17 Archaeopriapulida May not actually belong to Ottoia?18
Ottoia prolifica reconstruction source ↗
Haplophrentis H. carinatus Hyolithida One specimen found with several eocrinoids growing on its shell in life19
Reconstruction of Haplophrentis source ↗
Nisusia N. guizhouensis, N. granosa Kutorginida One of the few rhynchonelliforms known from the Cambrian20
N. burgessensis from the Burgess Shale source ↗
Kailidiscus K. chinensis Edrioasteroidea Strongly resembles other echinoderm clades in several features21
Globeocrinus G. globulus Eocrinoidea Short-stalked, over three times as abundant as Sinoeocrinus22
Sinoeocrinus S. lui Eocrinoidea Synonymous with a wide range of other proposed eocrinoids, has a complex ontogeny8
Fossil of Sinoeocrinus source ↗
Turbanicystis T. inflata Eocrinoidea Has a very short but broad stalk, which likely secreted a "glue" to cement it to substrate23
Pararotadiscus P. guizhouensis Eldoniidae Small brachiopods and echinoderms likely grew on some specimens in life24
Fossil of P. guizhouensis source ↗
Dinomischus D. isolatus? Dinomischidae (stem-Ctenophora) Only known from one specimen25
Reconstruction of two D. isolatus in their environment source ↗
Angulosuspongia A. sinensis Vauxiidae (Demospongiae) First non-Laurentian vauxiid,26 bears silliceous spicules27
Allonnia A. phrixothrix, A. erjiensis Chancelloriidae Latter species has especially dense sclerites28
Reconstruction of A. erjiensis (left) and A. phrixothrix (right) source ↗
Archiasterella A. anchoriformis Chancelloriidae One of the two species in the genus known from complete fossils28
Chancelloria C. zhaoi, C. eros Chancelloriidae One specimen of the latter species has a smaller C. eros growing on top of it28
Fossil of C. eros from the Wheeler Shale source ↗

Other taxa

Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
Other taxa
Genus Species Higher taxon Notes Images
Parafunaria P. sinensis Bryophyta? Possibly the earliest embryophyte fossil,6 but this has been doubted due to insufficient evidence7
Parallelphyton P. tipica Viridiplantae? Bears differentiation similar to "proto-plants" and the extant Fritschiella29
Walcottophycus W. gyges Bryopsidales? Formerly placed within Bosworthia30
Fossil of W. gyges source ↗

GSSP for the Cambrian Series 3

An outcrop of the Kaili Formation, the Wuliu-Zengjiayan section, was a candidate for the GSSP for the beginning of the 5th stage of the Cambrian. The FAD of two trilobites from the formation are proposed to be the official stage boundary, Oryctocephalus indicus and Ovatoryctocara granulata. Both can be correlated with formations of similar age in Siberia and China.31 In 2018, GSSP for the Miaolingian series (Cambrian Series 3, "Middle" Cambrian32) as well as the Wuliuan stage was finally defined in this formation.33

References

References

  1. Wang, Y.; Lin, J. P.; Zhao, Y. L.; Orr, P. J. (2009). "Palaeoecology of the trace fossil Gordia and its interaction with nonmineralizing taxa from the early Middle Cambrian Kaili Biota, Guizhou Province, South China". Palaeogeography, Palaeoclimatology, Palaeoecology. 277 (1–2): 141–148. Bibcode:2009PPP...277..141W. doi:10.1016/j.palaeo.2009.02.017.
  2. Lin, J. P.; Gon, S. M.; Gehling, J. G.; Babcock, L. E.; Zhao, Y. L.; Zhang, X. L.; Hu, S. X.; Yuan, J. L.; Yu, M. Y.; Peng, J. (2006). "A Parvancorina-like arthropod from the Cambrian of South China". Historical Biology. 18 (1): 33–45. Bibcode:2006HBio...18...33L. doi:10.1080/08912960500508689. S2CID 85821717.
  3. Zhang, Xingliang; Wei Liu; Yuanlong Zhao (2008). "Cambrian Burgess Shale-type Lagerstätten in South China: Distribution and significance" (PDF). Gondwana Research. 14 (1–2): 255–262. Bibcode:2008GondR..14..255Z. doi:10.1016/j.gr.2007.06.008. Archived from the original (PDF) on 2014-07-14.
  4. ZHAO Yuanlong; YUAN Jinliang; ZHU Maoyan; YANG Ruidong; GUO Qingjun; PENG Jin; YANG Xinglian (2002). "Progress and significance in research on the early Middle Cambrian Kaili Biota, Guizhou Province, China". Progress in Natural Science. 12 (9): 649–654.
  5. Lin, J.; et al. (2006). "Silicified egg clusters from a Middle Cambrian Burgess Shale–type deposit, Guizhou, south China". Geology. 34 (12): 1037–1040. Bibcode:2006Geo....34.1037L. doi:10.1130/G23006A.1.
  6. Yang, Rui-Dong; Mao, Jia-Ren; Zhang, Wei-Hua; Jiang, Li-Jun; Gao, Hui (2004). "Bryophyte-like Fossil (Parafunaria sinensis) from Early-Middle Cambrian Kaili Formation in Guizhou Province, China". Acta Botanica Sinica. 46 (2): 180–185.
  7. Vanderpoorten, Alain; Goffinet, Bernard (2010). Introduction to Bryophyes (Repr ed.). Cambridge: Cambridge Univ. Pr. ISBN 978-0-521-70073-3.
  8. Parsley, Ronald L.; Zhao Yuanlong (2006). "Long stalked eocriuoids in basal Middle Cambrian Kaili Biota, Taijiang County, Guizhou Province, China". Journal of Paleontology. 80 (6): 1058–1071. doi:10.1666/0022-3360(2006)80[1058:LSEITB]2.0.CO;2. ISSN 0022-3360. S2CID 128645059.
  9. Legg, D.A. (30 September 2015). "The morphology and affinities of Skania fragilis (Arthropoda) from the middle Cambrian Burgess Shale". Bulletin of Geosciences: 509–518. doi:10.3140/bull.geosci.1532.
  10. Lin, Jih-Pai (1 January 2007). "Preservation of the Gastrointestinal System in Olenoides (Trilobita) from the Kaili Biota (Cambrian) of Guizhou, China". Memoirs of the Association of Australasian Palaeontologists (33): 179–189. doi:10.3316/informit.252092135956343.
  11. Yuan, Jinliang; Peng, Jin; Zhao, Yuanlong (August 2011). "New Bivalved Arthropods from Mid‐Cambrian Kaili Biota of Southeastern Guizhou, Southwest China". Acta Geologica Sinica - English Edition. 85 (4): 758–764. doi:10.1111/j.1755-6724.2011.00481.x.
  12. Wen, Rong-Qin; Zhao, Yuan-Long; Peng, Jin (March 2015). "Morphology and ontogeny of Tuzoia bispinosa from the Kaili Biota (Cambrian Stage 5) of eastern Guizhou, China". Palaeoworld. 24 (1–2): 61–70. doi:10.1016/j.palwor.2014.12.005.
  13. Lan, Tian; Zhao, Yuanlong; Zhao, Fangchen; He, You; Martinez, Pedro; Strausfeld, Nicholas J. (October 2021). "Leanchoiliidae reveals the ancestral organization of the stem euarthropod brain". Current Biology. 31 (19): 4397–4404.e2. doi:10.1016/j.cub.2021.07.048.
  14. Zhu, M. -Y.; Vannier, J.; Iten, H. Van; Zhao, Y. -L. (2004). "Direct Evidence for Predation on Trilobites in the Cambrian" (PDF). Proceedings: Biological Sciences. 271: S277–S280. ISSN 0962-8452.
  15. Zhang, Xingliang; Zhao, Yuanlong; Yang, Ruidong; Shu, Degan (2002). "The Burgess Shale Arthropod Mollisonia (M. sinica New Species): New Occurrence from the Middle Cambrian Kaili Fauna of Southwest China" (PDF). Journal of Paleontology. 76 (6): 1106–1108. ISSN 0022-3360.
  16. Luo, Xiuchun; Yang, XingLian; Esteve, Jorge; Wang, Dezhi (September 2025). "First report of the hurdiid radiodont Ursulinacaris from the Cambrian Kaili Biota, South China". Palaeogeography, Palaeoclimatology, Palaeoecology. 674 113036. doi:10.1016/j.palaeo.2025.113036. ISSN 0031-0182.
  17. Yang, Yuning; Zhao, Yuanlong; Zhang, Xingliang (2 June 2016). "Fossil priapulid Ottoia from the Kaili biota (Cambrian Series 3) of South China". Journal of Systematic Palaeontology. 14 (6): 527–543. doi:10.1080/14772019.2015.1077900.
  18. Smith, Martin R.; Harvey, Thomas H. P.; Butterfield, Nicholas J. (July 2015). "The macro‐ and microfossil record of the Cambrian priapulid Ottoia". Palaeontology. 58 (4): 705–721. doi:10.1111/pala.12168.
  19. Liu, Xiong; Zhao, Yuanlong; Yang, Xinglian; Chen, Zhengpeng; Chen, Shengguang; Luo, Xue (January 2023). "Stalked eocrinoids attached onto hyolithids with helens from Cambrian Kaili Formation in Jianhe, Guizhou, South China". Palaeogeography, Palaeoclimatology, Palaeoecology. 610 111330. doi:10.1016/j.palaeo.2022.111330.
  20. Mao, Yong-Qin; Zhao, Yuan-Long; Wang, Cheng-Wen; Topper, Timothy (February 2017). "A fresh look at Nisusia Walcott, 1905 from the Cambrian Kaili Formation in Guizhou". Palaeoworld. 26 (1): 12–24. doi:10.1016/j.palwor.2016.03.001.
  21. Zhao, Yuanlong; Sumrall, Colin D.; Parsley, Ronald L.; Peng, Jin (July 2010). "Kailidiscus, a new plesiomorphic edrioasteroid from the basal Middle Cambrian Kaili biota of Guizhou Province, China". Journal of Paleontology. 84 (4): 668–680. doi:10.1666/09-159.1.
  22. Zhao, Yuanlong; Parsley, Ronald L.; Peng, Jin (March 2008). "Basal Middle Cambrian short-stalked eocrinoids from the Kaili biota: Guizhou province, China". Journal of Paleontology. 82 (2): 415–422. doi:10.1666/06-041.1.
  23. Parsley, Ronald L.; Zhao, Yuanlong (2010). "A New Turban-Shaped Gogiid Eocrinoid from the Kaili Formation (kaili Biota), Balang, Jianhe County, Guizhou Province, China" (PDF). Journal of Paleontology. 84 (3): 549–553. ISSN 0022-3360.
  24. Zhao, Yuanlong; Wang, Mingkun; LoDuca, Steven T.; Yang, Xinglian; Yang, Yuning; Liu, Yujuan; Cheng, Xin (2018). "Paleoecological Significance of Complex Fossil Associations of the Eldonioid Pararotadiscus guizhouensis with other Faunal Members of the Kaili Biota (Stage 5, Cambrian, South China)" (PDF). Journal of Paleontology. 92 (6): 972–981. ISSN 0022-3360.
  25. Jin, Peng; Yuanlong, Zhao; Jih-Pai, Lin (7 September 2010). "Dinomischus from the Middle Cambrian Kaili Biota, Guizhou, China". Acta Geologica Sinica - English Edition. 80 (4): 498–501. doi:10.1111/j.1755-6724.2006.tb00269.x.
  26. Yang, Xinglian; Zhao, Yuanlong; Babcock, Loren E.; Peng, Jin (November 2017). "A new vauxiid sponge from the Kaili Biota (Cambrian Stage 5), Guizhou, South China". Geological Magazine. 154 (6): 1334–1343. doi:10.1017/S0016756816001229.
  27. Yang, X.-L.; Zhao, Y.-L.; Babcock, L. E.; Peng, J. (21 February 2017). "Siliceous spicules in a vauxiid sponge (Demospongia) from the Kaili Biota(Cambrian Stage 5), Guizhou, South China". Scientific Reports. 7 (1). doi:10.1038/srep42945.
  28. Peng, Tingzu; Yang, Yuning; Yun, Hao; Yang, Xinglian; Zhang, Qianqian; He, Min; Chi, Xiangri; Liu, Jing; Liu, Xi (2 July 2024). "Flourishing chancelloriids from the Cambrian Kaili Biota of South China". Historical Biology. 36 (7): 1302–1320. doi:10.1080/08912963.2023.2212382.
  29. Wu, MengYin; Zhao, YuanLong; Tong, JinNan; Yang, RuiDong (January 2011). "New macroalgal fossils of the Kaili Biota in Guizhou Province, China". Science China Earth Sciences. 54 (1): 93–100. doi:10.1007/s11430-010-4063-3.
  30. Wu, Mengyin; LoDuca, Steven T.; Zhao, Yuanlong; Xiao, Shuhai (July 2016). "The macroalga Bosworthia from the Cambrian Burgess Shale and Kaili biotas of North America and China". Review of Palaeobotany and Palynology. 230: 47–55. doi:10.1016/j.revpalbo.2016.04.001.
  31. Rozanov, A. Yu.; Maoyan Zhu; K. L. Pak; P. Yu. Parkhaev (2008). "The 2nd Sino-Russian Symposium on the Lower Cambrian Subdivision". Paleontological Journal. 42 (4): 441–446. Bibcode:2008PalJ...42..441R. doi:10.1134/S0031030108040151. S2CID 129626166.
  32. Arne Thorshøj Nielsen, Per Ahlberg (2019). "The Miaolingian, a new name for the 'Middle' Cambrian (Cambrian Series 3): identification of lower and upper boundaries in Baltoscandia". GFF. 141 (2): 162–173. Bibcode:2019GFF...141..162N. doi:10.1080/11035897.2019.1621374.
  33. Yuanlong Zhao; Jinliang Yuan; Loren E. Babcock; Qingjun Guo; Jin Peng; Leiming Yin; Xinglian Yang; Shanchi Peng; Chunjiang Wang; Robert R. Gaines; Jorge Esteve; Tongsu Tai; Ruidong Yang; Yue Wang; Haijing Sun; Yuning Yang (June 2019). "Global Standard Stratotype-Section and Point (GSSP) for the conterminous base of the Miaolingian Series and Wuliuan Stage (Cambrian) at Balang, Jianhe, Guizhou, China" (PDF). Episodes. 42 (2): 165–184. doi:10.18814/epiiugs/2019/019013. Archived (PDF) from the original on 2022-03-04. Retrieved 19 March 2024.