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Kitadani Formation

Summary

The Kitadani Formation (Japanese: 北谷層 Kitadani-sō) is a unit of Lower Cretaceous sedimentary rock which crops out near the city of Katsuyama in Fukui Prefecture, Japan, and it is the primary source of Cretaceous-aged non-marine vertebrate fossils in Japan. Dinosaur remains are among the fossils that have been recovered from the formation, but it also preserves a diverse assemblage of plants, invertebrates, and other vertebrates.[2] Most, if not all, of the fossil specimens collected from the Kitadani Formation are reposited at the Fukui Prefectural Dinosaur Museum.[3]

Kitadani Formation
Stratigraphic range: Barremian-Aptian
~125–115 Ma
The Kitadani Dinosaur Quarry Bonebed I, where an outcrop of the Kitadani Formation can be found; the white arrow indicates the location of the type locality of Tyrannomimus fukuiensis. Photographed in c. 2023.
TypeGeological formation
Unit ofTetori Group
UnderliesOmichidani Formation
OverliesAkaiwa Formation
Thickness~100 m (330 ft)[1]
Lithology
PrimaryTuff, sandstone, shale
OtherCoal
Location
Coordinates36°06′N 136°36′E / 36.1°N 136.6°E / 36.1; 136.6
Approximate paleocoordinates47°18′N 137°42′E / 47.3°N 137.7°E / 47.3; 137.7
Region Fukui Prefecture
Country Japan
Type section
Named byUnknown[1]
Kitadani Formation is located in Japan
Kitadani Formation
Kitadani Formation (Japan)

The Kitadani Formation is a unit within the Tetori Group, a major sequence of Lower Cretaceous rocks that is distributed across Fukui, Ishikawa, and Gifu prefectures of western-central Honshu. The Tetori Group exhibits marked lateral variation, and the Kitadani Formation is only present in Fukui Prefecture.[1] The Kitadani Formation comprises interbedded tuffs, sandstones, and shales and reaches a maximum thickness of approximately one hundred meters (~328 feet).[1] It conformably overlies the Akaiwa Formation and is unconformably overlain by the Omichidani Formation.[4] The Kitadani Formation is significant because it is the major source of dinosaur fossils in Japan and because of Japan's unique position along the northeastern margin of Eurasia during the Early Cretaceous.

Geology edit

The Kitadani Formation is a unit within the Tetori Group, a Lower Cretaceous sequence of predominantly sedimentary rock which crops out in the Fukui, Ishikawa, and Gifu prefectures of west-central Honshu, Japan in the region surrounding Mount Haku.[1][5]

The formations present within the Tetori Group vary laterally, and the Kitadani Formation crops out only in the Kuzuryū River district of Fukui Prefecture. In this region, the sequence comprises, in ascending stratigraphic order: Gomijima Formation, the Kuwajima Formation, the Akaiwa Formation, and Kitadani Formation.[1] The Kitadani Formation comprises alternating horizons of red-brown tuffs, blackish shales and sandstones, and thin coal beds. The sandstones within the Kitadani Formation are light gray and green and range in clast size from fine to coarse. The type section of the Kitadani Formation occurs along the Nakanomatadani branch of the Takinami River [ja] near the city of Katsuyama, where it is approximately 100 m (~328 feet) in thickness. The Kitadani Formation conformably overlies the Akaiwa Formation and is unconformably overlain by the Omichidani Formation.[1]

The palaeoclimate during the deposition of the formation was noticeably warmer and drier than that of the older Kuwajima and Okurodani Formations, as evidenced by oxygen isotope records as well as by the presence of crocodylomorph fossils in the former in contrast to their absence in the latter.[6]

The Kitadani Formation has had varying nomenclature throughout the history of its study.[1] In the early stratigraphic literature on the Tetori Group, the Kitadani Formation was variably referred to as the "Lower part of the Omichidani Formation",[7] the "Chinaboradani Alternation of Tuff, Shale, and Sandstone",[8] the "Kitadani Alternation of Sandstone, Shale, and Tuff",[9] and simply the "Kitadani Alternation"[10] prior to its designation as a formation.[1]

Age edit

The Kitadani Formation was biostratigraphically dated to the late Barremian and early Aptian ages of the Early Cretaceous Epoch in 2002 based upon the presence of the freshwater bivalve Nippononaia ryosekiana.[11] In 2005, part of the Kitadani Formation was biostratigraphically dated to the Barremian Age based upon the occurrence of the charophyte gyrogonite Clavator harrisii reyi in association with other charophytes.[12] These biostratigraphic age assignments are supported by zircon fission track radioisotopic ages of tuff, which date the Kitadani Formation to 127-115 Ma.[13]

Fossil assemblage edit

The Kitadani Formation preserves a diverse assemblage of plant fossils; invertebrate fossils; and vertebrate body and trace fossils, including mammals, turtles, crocodylomorphs, and dinosaurs. Many vertebrate specimens from the Kitadani Formation are incomplete and poorly preserved, so taxonomic diversity is likely higher than it seems.

Plant fossils edit

The plant fossil assemblage of the Kitadani Formation is characterized by a rarity of ferns and an abundance of cycadales and conifers represented mostly by cones and shoots.[14] A palynological study in 2013 resulted in the identification of greater than 40 species of spores, pollen grains, and plant fragments from the Kitadani Formation representing gymnosperms, freshwater algae, and epiphyllous fungus; however, no angiosperm pollen was identified.[15] Branches of the conifer Brachyphyllum obesum have been recovered, which was interpreted to represent the warming and possible drying of the climate toward the upper Tetori Group.[16] This interpretation is supported by the lack of plants from lower in the Tetori Group, such as ginkgos, in the Kitadani Formation.[17]

Invertebrate fossils edit

The invertebrate fossil assemblage of the Kitadani Formation mostly comprises freshwater and brackish water bivalve and gastropod mollusks.[18]

Molluscs reported from the Kitadani Formation
Genus Species Location Stratigraphic position Material Notes Images
Unio U (?). ogamigoensis Unionid bivalve
Plicatounio P. naktongensis naktongensis
P. naktongensis multiplicatus
Nagdongia N. soni (or Nakamuranaia chingshanensis)
Pseudohyria P. matsumotoi
P. sp. cf. matsumotoi
Nippononaia N. ryosekiana
N. tetoriensis
Trigonioides T. (Wakinoa) tetoriensis
Viviparus V. onogoensis Architaenioglossan gastropod
Planorbidae Indeterminate Hygrophilan gastropod
Insects reported from the Kitadani Formation
Genus Species Location Stratigraphic position Material Notes Images
?Morphna ?M. sp. Blaberidae
Petropterix P. fukuiensis Umenocoleidae
Praeblattella P. inexpecta Mesoblattinidae
P. arcuata
?Vitisma ?V. sp. Umenocoleidae
Ostracods reported from the Kitadani Formation
Genus Species Location Stratigraphic position Material Notes Images
Cypridea C. angusticaudata Ostracod
C. (Morinia) monosulcata zhejiangensis
C. (Bisulcocypridea) sp.
Timiriasevia Indeterminate

Vertebrate fossils edit

Actinopterygii edit

Fishes reported from the Kitadani Formation
Genus Species Location Stratigraphic position Material Notes Images
Amiiformes[19] indeterminate Kitadani Dinosaur Quarry Bonebed I Scales
?Lepidotes ?L. sp. Scales

Mammaliaformes edit

Mammaliaformes reported from the Kitadani Formation
Genus Species Location Stratigraphic position Material Notes Images
Symmetrolestes S. parvus North of Kitadani Dinosaur Quarry Bonebed Fragmentary right mandible Spalacotheriid
Eobaataridae Indeterminate Kitadani Dinosaur Quarry Bonebed I A left p4 crown
?Triconodontidae Indeterminate Kitadani Dinosaur Quarry Bonebed I "a fragment of possible right dentary with a damaged molariform crown and roots"

Testudines edit

Turtles are represented mostly by shell fragments within the Kitadani Formation.[20][21]

Turtles reported from the Kitadani Formation
Genus Species Location Stratigraphic position Material Notes Images
Adocidae Indeterminate Shell Different with Adocus from the same formation
Adocus A. sp. Kitadani Dinosaur Quarry Bonebed I Shell
Nanshiungchelyidae Indeterminate Kitadani Dinosaur Quarry Bonebed I Shell
?Sinemydidae Indeterminate Kitadani Dinosaur Quarry Bonebed I Shell
Testudinoidea Indeterminate Kitadani Dinosaur Quarry Bonebed I Shell
Trionychidae Indeterminate Kitadani Dinosaur Quarry Bonebed I Shell
Xinjiangchelyidae Indeterminate Shell

Crocodylomorpha edit

 
Undescribed Kitadani goniopholidid

A nearly complete skeleton of goniopholidid has been discovered from the Kitadani Formation, but this material remains undescribed.[22]

Crocodylomorpha reported from the Kitadani Formation
Genus Species Location Stratigraphic position Material Notes Images
Goniopholididae indeterminate Kitadani Dinosaur Quarry (Unspecified) Partial skeleton including cranial remains Phylogenetic analysis suggests that it a basal member of the group similar in position to Siamosuchus and Sunosuchus.[23]

Dinosauria edit

Dinosaurs are among the most well-known vertebrate taxa from the Kitadani Formation. Taxa from all three major dinosaurian clades — Theropoda, Sauropodomorpha, and Ornithischia — have been recovered.[2]

Dinosaurs reported from the Kitadani Formation
Genus Species Location Stratigraphic position Material Notes Images
Ankylosauria Indeterminate Teeth Family unknown
Fukuipteryx[24] F. prima Kitadani Dinosaur Quarry (Unspecified) Associated disarticulated partial skeleton Avialan  
Fukuiraptor[25] F. kitadaniensis Kitadani Dinosaur Quarry Bonebed I Multiple individuals showing different ontogenetic stages Basal megaraptoran

 

Fukuisaurus[26] F. tetoriensis Kitadani Dinosaur Quarry Bonebed I Multiple specimens representing a partial skeleton Hadrosauroid  
Fukuititan[27] F. nipponensis Kitadani Dinosaur Quarry Bonebed II Associated partial skeleton Titanosauriform  
Fukuivenator[28] F. paradoxus Kitadani Dinosaur Quarry Partial skeleton with skull Basal therizinosaur or some other kind of basal maniraptoran
 
Koshisaurus[26] K. katsuyama Kitadani Dinosaur Quarry Bonebed IV Partial skeleton Hadrosauroid
 
Spinosauridae Indeterminate Kitadani Dinosaur Quarry Bonebed I 18 Teeth Subfamily unknown
Tyrannomimus[29] T. fukuiensis Kitadani Dinosaur Quarry Bonebed I Isolated remains from multiple individuals The earliest definitive deinocheirid
 

Ichnofossils edit

Undescribed tracks of ankylosaurs and sauropods have been discovered from the Kitadani Formation.

Ichnofossils reported from the Kitadani Formation
Genus Species Location Stratigraphic position Material Notes Images
Amblydactylus A. isp. Ornithopod tracks.
Aquatilavipes A. isp. Bird tracks
Asianopodus A. isp. Small to medium-sized tridactyl theropod tracks.
Caririchnium C. isp. Ornithopod tracks
Eubrontidae Indeterminate Large tridactyl theropod tracks.
Grallatoridae Indeterminate Small to medium-sized tridactyl theropod tracks
cf. Gyeongsangornipes cf. G. isp. Bird tracks.
Minisauripus M. isp. The smallest theropod track from the Kitadani Formation.
Ornithomimipodidae Indeterminate Slender-toed tridactyl theropod tracks.
Pteraichnus P. nipponensis Pterosaur tracks; The first pterosaur ichnofossil reported in Japan.

Eggs edit

Eggs reported from the Kitadani Formation
Genus Species Location Stratigraphic position Material Notes Images
Plagioolithus[30] P. fukuiensis Three-layered eggshell interpreted as a fossil avian egg.

See also edit

References edit

  1. ^ a b c d e f g h i Kusuhashi, N.; Matsuoka, H.; Kamiya, H.; Setoguchi, T. (2002). "Stratigraphy of the late Mesozoic Tetori Group in the Hakusan Region, central Japan : an overview". Memoirs of the Faculty of Science, Kyoto University. Series of Geology and Mineralogy. 59 (1): 9–31.
  2. ^ a b Weishampel, D.B.; et al. (2004). "Dinosaur distribution (Early Cretaceous, Asia)." In: Weishampel, D.B.; Dodson, P.; and Osmólska, H. (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 563-570. ISBN 0-520-24209-2.
  3. ^ "FPDM: Fukui Prefectural Dinosaur Museum".
  4. ^ Tsubamoto, T.; Rougier, G.W.; Isaji, S.; Manabe, M.; Forasiepi, A.M. (2004). "New Early Cretaceous spalacotheriid "symmetrodont" mammal from Japan". Acta Palaeontologica Polonica. 49 (3): 329–346.
  5. ^ Yamada, Toshihiro; Sano, Shin-ichi (2018). "Designation of the Type Section of the Tetori Group and Redefinition of the Kuzuryu Group distributed in Central Japan". Memoir of the Fukui Prefectural Dinosaur Museum. 17: 89–94. Retrieved 25 February 2023.
  6. ^ Amiot, Romain; Kusuhashi, Nao; Saegusa, Haruo; Shibata, Masateru; Ikegami, Naoki; Shimojima, Shizuo; Sonoda, Teppei; Fourel, François; Ikeda, Tadahiro; Lécuyer, Christophe; Philippe, Marc; Wang, Xu (January 2021). "Paleoclimate and ecology of Cretaceous continental ecosystems of Japan inferred from the stable oxygen and carbon isotope compositions of vertebrate bioapatite". Journal of Asian Earth Sciences. 205: 104602. Bibcode:2021JAESc.20504602A. doi:10.1016/j.jseaes.2020.104602. S2CID 228820808.
  7. ^ Maeda, S. (1953). "The Mesozoic in north of Katsuyama, Fukui Prefecture". Journal of the Geological Society of Japan. 59: 323–324.
  8. ^ Maeda, S. (1957). "Stratigraphy and geological structure of the Tetori Group along the Uchinami and Itoshiro rivers". Journal of the Geological Society of Japan. 63 (741): 357–365. doi:10.5575/geosoc.63.357.
  9. ^ Maeda, S. (1958). "Stratigraphy and geological structure of the Tetori Group in the Hakusan district (Part 1. Stratigrphy)". Journal of the Geological Society of Japan. 64 (758): 583–594. doi:10.5575/geosoc.64.583.
  10. ^ Maeda, S. (1961). "On the geological history of the Mesozoic Tetori Group in Japan". Journal of College of Arts and Sciences, Chiba University. 3: 396–426.
  11. ^ Kozai, T.; Ishida, K.; Park, S.O.; Chang, K.H. (2002). "Early Cretaceous non-marine bivalves from Korea and Japan". Abstracts of the 2002 Meeting of the Palaeontological Society of Japan: 16–17.
  12. ^ Kubota, K. (2005). "Charophyte gyrogonites from the Lower Cretaceous Kitadani Formation of the Tetori Group in the Takinamigawa area, Katsuyama City, Fukui Prefecture, central Japan". Paleontological Research. 9 (2): 203–213. doi:10.2517/prpsj.9.203. S2CID 129324272.
  13. ^ Fujita, M. (2003). "Geological age of the vertebrate-bearing horizons in the Tetori Group". Memoirs of the Fukui Prefectural Dinosaur Museum. 2: 3–14.
  14. ^ Yabe, A.; Terada, K.; Sekido, S. (2003). "The Tetori-type flora, revisited: a review". Memoir of the Fukui Prefectural Dinosaur Museum. 2: 23–42.
  15. ^ Legrand, J.; Pons, D.; Terada, K.; Yabe, A.; Nishida, H. (2013). "Lower Cretaceous (Upper Barremian-Lower Aptian?) palynoflora from the Kitadani Formation (Tetori Group, Inner Zone of Central Japan)". Paleontological Research. 17 (3): 201–229. doi:10.2517/1342-8144-17.3.201. S2CID 129603779.
  16. ^ Yabe, A.; Kubota, K. (2004). "Brachyphyllum obesum, newly discovered thermophilic conifer branch from the Lower Cretaceous Kitadani Formation of the Tetori Group, central Japan". Memoir of the Fukui Prefectural Dinosaur Museum. 3: 23–29.
  17. ^ Suzuki, S. Shibata; Azuma, Y.; Yukawa, H.; Sekiya, T.; Masaoka, Y. (2015). "Sedimentary environment of dinosaur fossil bearing successions of the Lower Cretaceous Kitadani Formation, Tetori Group, Katsuyama City, Fukui, Japan". Memoir of the Fukui Prefectural Dinosaur Museum. 14: 1–9.
  18. ^ Azuma Y. 2003. Early Cretaceous vertebrate remains from Katsuyama City, Fukui Prefecture, Japan. Mem Fukui Prefect Dinosaur Mus. 2:17–21.
  19. ^ Azuma Y. 2003. Early Cretaceous vertebrate remains from Katsuyama City, Fukui Prefecture, Japan. Mem Fukui Prefect Dinosaur Mus. 2:17–21.
  20. ^ Sonoda T, Azuma Y, Hirayama R, Ando H. (2015) New trionychoid specimens and turtle fauna from the Lower Cretaceous Kitadani Formation of the Tetori Group in central Japan. PeerJ PrePrints 3:e949v1 https://doi.org/10.7287/peerj.preprints.949v1
  21. ^ Hirayama, R. (2002) Preliminary report of the fossil turtles from the Kitadani Formation (Early Cretaceous) of the Tetori Group of Katsuyama, Fukui Prefecture, Central Japan. Memoirs of the Fukui Prefectural Dinosaur Museum. 1: 29-40.
  22. ^ Kobayashi, Y (1998). "A new goniopholid from the Early Cretaceous Kitadani Formation, Fukui Prefecture, Japan". Journal of Vertebrate Paleontology. 18 (3): 56A.
  23. ^ Obuse, Shota; Shibata, Masateru (January 2024). "New goniopholidid specimens from the Lower Cretaceous Kitadani Formation, Tetori Group, Japan". Annales de Paléontologie. 110 (1): 102661. doi:10.1016/j.annpal.2023.102661.
  24. ^ Imai, Takuya; Azuma, Yoichi; Kawabe, Soichiro; Shibata, Masateru; Miyata, Kazunori; Wang, Min; Zhou, Zhonghe (December 2019). "An unusual bird (Theropoda, Avialae) from the Early Cretaceous of Japan suggests complex evolutionary history of basal birds". Communications Biology. 2 (1): 399. doi:10.1038/s42003-019-0639-4. ISSN 2399-3642. PMC 6856171. PMID 31754639.
  25. ^ Currie, P.J.; Azuma, Y. (2006). "New specimens, including a growth series, of Fukuiraptor (Dinosauria, Theropoda) from the Lower Cretaceous Kitadani Quarry of Japan". J. Paleont. Soc. Korea. 22 (1): 173–193
  26. ^ a b Shibata, Masateru; Azuma, Yoichi (2015). "New basal hadrosauroid (Dinosauria: Ornithopoda) from the Lower Cretaceous Kitadani Formation, Fukui, central Japan" (PDF). Zootaxa. 3914 (4): 421–40. doi:10.11646/zootaxa.3914.4.3. PMID 25661952.|
  27. ^ Azuma, Y.; Shibata, M. (2010). "Fukuititan nipponensis, a new titanosauriform sauropod from the Early Cretaceous Tetori Group of Fukui Prefecture, Japan". Acta Geologica Sinica - English Edition. 84 (3): 454–462. doi:10.1111/j.1755-6724.2010.00268.x.
  28. ^ Azuma, Y.; Xu, X.; Shibata, M.; Kawabe, S.; Miyata, K.; Imai, T. (2016). "A bizarre theropod from the Early Cretaceous of Japan highlighting mosaic evolution among coelurosaurians". Scientific Reports. 6: 20478. Bibcode:2016NatSR...620478A. doi:10.1038/srep20478. PMC 4763874. PMID 26908367.
  29. ^ Hattori, S.; Shibata, M.; Kawabe, S.; Imai, T.; Nishi, H.; Azuma, Y. (2023). "New theropod dinosaur from the Lower Cretaceous of Japan provides critical implications for the early evolution of ornithomimosaurs". Scientific Reports. 13. 13842. doi:10.1038/s41598-023-40804-3. PMC 10484975.
  30. ^ Imai, Takuya; Azuma, Yoichi (2015). "The oldest known avian eggshells, Plagioolithus fukuiensis, from the Lower Cretaceous (upper Barremian) Kitadani Formation, Fukui, Japan". Historical Biology. 27 (8): 1090–1097. Bibcode:2015HBio...27.1090I. doi:10.1080/08912963.2014.934232. S2CID 129113738.

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