The Akaiwa Formation (Japanese: 赤岩層, romanized: Akaiwa-sō) is an Early Cretaceous (Hauterivian-Barremian) geologic formation in central Honshu, Japan.[1] Indeterminate ornithischian fossils are known from the formation. Fossil ornithopod tracks have been reported from the formation.[2] As well as the turtle Kappachelys[3]
| Akaiwa Formation | |
|---|---|
| Stratigraphic range: Hauterivian-Barremian ~ | |
| Type | Geological formation |
| Unit of | Tetori Group |
| Underlies | Kitadani Formation |
| Overlies | Kuwajima Formation |
| Lithology | |
| Primary | Sandstone, conglomerate |
| Location | |
| Coordinates | 36°12′N 136°42′E / 36.2°N 136.7°E |
| Approximate paleocoordinates | 46°06′N 138°18′E / 46.1°N 138.3°E |
| Region | Honshu |
| Country |  Japan |
  Akaiwa Formation (Japan) | |
Fossil content edit
The following fossils have been reported from the formation:[1]
- Osteichthyes indet. - 'fish scales'
- Reptiles
- Turtles
- Crocodylomorpha indet. - isolated teeth of small crocodiles[4]
- ?Euornithopoda indet.
- Neochoristodera indet. - a nearly complete right premaxilla[5]
- Ornithopoda indet. - isolated teeth of small ornithopods
- ?Theropoda indet.
- Ichnofossils
- Ornithischia indet. - tracks[6]
See also edit
References edit
- ^ a b Akaiwa Formation in the Paleobiology Database
- ^ Weishampel et al., 2004, pp.517-607
- ^ a b Hirayama et al., 2013
- ^ Matsukawa & Obata, 1994
- ^ Matsumoto et al., 2014
- ^ Azuma & Tomida, 1995
Bibliography edit
- Matsumoto, R.; M. Manabe, and S. E. Evans. 2014. The first record of a long-snouted chrositodere (Reptilia, Diapsida) from the Early Cretaceous of Isihikawa Prefecture, Japan. Historical Biology 27. 583–594. .
- Hirayama, R.; S. Isaji, and T. Hibino. 2013. Kappachelys okurai gen. et sp. nov., a new stem soft-shelled turtle from the Early Cretaceous of Japan. In D. B. Brinkman, P. A. Holroyd, J. D. Gardner (eds.), 179–185. Morphology and Evolution of Turtles.
- Weishampel, David B.; Peter Dodson, and Halszka Osmólska (eds.). 2004. The Dinosauria, 2nd edition, 1–880. Berkeley: University of California Press. Accessed 2019-02-21. ISBN 0-520-24209-2
- Azuma, Y., and Y. Tomida. 1995. Early Cretaceous dinosaur fauna of the Tetori Group in Japan. In A. Sun, Y. Wang (eds.), 125–131. Sixth Symposium on Mesozoic Terrestrial Ecosystems and Biota, Short Papers.
- Matsukawa, M., and I. Obata. 1994. Dinosaurs and sedimentary environments in the Japanese Cretaceous: a contribution to dinosaur facies in Asia based on molluscan palaeontology and stratigraphy. Cretaceous Research 15. 101–125. .