Tamayama Formation Explained

Tamayama Formation
Type:	Geological formation
Period:	Coniacian-Santonian
Prilithology:	Sandstone
Otherlithology:	Siltstone
Region:	northern Honshu
Country:	Japan
Unitof:	Futaba Group
Subunits:	Kohisagawa Member, Irimaza Member
Underlies:	Unconformity with the Eocene Iwaki Formation
Overlies:	Kasamatsu Formation
Thickness:	~ 150 metres

The Tamayama Formation is a Coniacian-Santonian geologic formation in Japan. Dinosaur remains not referrable to the genus level are among the fossils that have been recovered from the formation.^[1] The lower and middle part of the formation consists of braided river sandstone, while the upper portion consists of upper shoreface to inner shelf sandstone.^[2] Vertebrate taxa from the formation include Futabasaurus and Cretalamna, along with titanosauriform teeth and neosuchian remains. Seeds of the nymphaeales plant Symphaenale futabensis are also known from this formation.

Fossils

Paleofauna

• Futabasaurus suzukii
• Cretalamna appendiculata^[3]
• Inoceramus
  • Inoceramus amakusensis
  • Inoceramus mihoensis
• Apiotrigonia minor^[3]
• Glycymeris? sp.^[3]
• Archaeromma chisatoi^[4]
• Titanosauriformes indet.^[5]
• Neosuchia indet.^[6]

Paleoflora

• Symphaenale futabensis^[7]
• Esgueiria sp.^[8]
• Hironoia sp.^[9]

See also

• List of dinosaur-bearing rock formations
  • List of stratigraphic units with few dinosaur genera

References

• Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. .

Notes and References

1. Weishampel, et al. (2004). "Dinosaur distribution." Pp. 517-607.
2. Ando. Hisao. Seishi. Masao. Oshima. Mitsuharu. Matsumaru. Tetsuya. 1995. Fluvial-Shallow Marine Depositional Systems of the Futaba Group (Upper Cretaceous). Depositional facies and sequences.. Journal of Geography (Chigaku Zasshi). 104. 2. 284–303. 10.5026/jgeography.104.284. 0022-135X. free.
3. Shimada, K.. Tsuihiji, T.. Sato, T.. Hasegawa, Y.. 2010. A remarkable case of a shark-bitten elasmosaurid plesiosaur. Journal of Vertebrate Paleontology. 30. 2. 592–597. 10.1080/02724631003621920. 2010JVPal..30..592S . 128760390 .
4. Aiba . H. . Inose . H. . A New False Fairy Wasp (Hymenoptera: Mymarommatoidea: Mymarommatidae) in Late Cretaceous Iwaki Amber from Futaba Group of Iwaki City, Fukushima Prefecture, Japan . 2024 . Paleontological Research . 28 . 3 . 1–8 . 10.2517/PR230020 .
5. Saegusa. H.. Tomida. Y.. 2011. Titanosauriform teeth from the Cretaceous of Japan. Anais da Academia Brasileira de Ciências. 83. 1. 247—265. 10.1590/S0001-37652011000100014.
6. Yoshida. J.. Takahashi. T.. Nabana. S.. 2023. A crocodyliform osteoderm from the Tamayama Formation（Upper Cretaceous） of Fukushima, Japan. Bulletin of the Fukushima Museum. 37. 29–36.
7. Takahashi. Masamichi. Friis. Else Marie. Crane. Peter R.. March 2007. Fossil Seeds of Nymphaeales from the Tamayama Formation (Futaba Group), Late Cretaceous (Early Santonian) of Northeastern Honshu, Japan. International Journal of Plant Sciences. en. 168. 3. 341–350. 10.1086/510414. 1058-5893.
8. Takahashi. M.. Crane. P.R.. Ando. H.. 1999-06-30. Esgueiria futabensis sp. nov., a new angiosperm flower from the Upper Cretaceous (lower Coniacian) of northeastern Honshu, Japan. Paleontological Research. 3. 2. 81–87.
9. Takahashi. M.. Crane. P.R.. Manchester. S.R.. 2002. Hironoia fusiformis gen. et sp. nov.; a cornalean fruit from the Kamikitaba locality (Upper Cretaceous, Lower Coniacian) in northeastern Japan. Journal of Plant Research. 115. 6. 463–473. 10.1007/s10265-002-0062-6.