Kaijima Island: Rupelian, Japan
collected by Toshiyuki Kamei; Hideo Ikeuchi; Yoshihiko Okazaki

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Chondrichthyes - Lamniformes - Otodontidae
6 specimens
Kamei specimen 1; Ikeuchi specimen 1, 3; KMNH VP 100,090; 100,091; 100,114
see common names

Geography
Country:Japan
Coordinates: 34.0° North, 130.8° East (view map)
Paleocoordinates:36.5° North, 127.6° East (Wright 2013)
Basis of coordinate:based on nearby landmark
Geographic resolution:outcrop
Time
Period: Paleogene Epoch: Oligocene
Stage: Rupelian 10 m.y. bin: Cenozoic 4
Key time interval: Rupelian
Age range of interval: 33.9 - 27.3 m.y. ago
Stratigraphy
Formation:Yamaga
Stratigraphic resolution:group of beds
Stratigraphy comments: The age of the Yamaga Formation in the Ashiya area was placed at 31.7±2.3 Ma (upper Lower Oligocene) based on fission track dating (Ozaki and Hamasaki, 1991). This was supported by further fission track dating and biostratigraphic studies conducted in the upper and lower formations (Tsuchi et al., 1987; Ozaki and Hamasaki, 1991; Okada, 1992). The Ashiya Group is correlated with the calcareous nannofossil Subzone CP19a of Okada and Bukry (1980) (Okada, 1992) and the planktonic foraminiferal Subzone P21a of Berggren and Miller (1988) (Ibaraki, 1994).
Lithology and environment
Primary lithology: "siliciclastic"
Environment:marine indet.
Taphonomy
Modes of preservation:body
Size of fossils:macrofossils
Collection methods and comments
Reason for describing collection:general faunal/floral analysis
Collectors:Toshiyuki Kamei; Hideo Ikeuchi; Yoshihiko Okazaki
Collection method comments: Repository: Kitakyushu Museum of Natural History
Metadata
Database number:278480
Authorizer:M. Clapham Enterer:M. Clapham
Modifier:M. Clapham Research group:vertebrate
Created:2026-03-24 19:59:35 Last modified:2026-03-24 20:14:27
Access level:the public Released:0000-00-00 00:00:00
Creative Commons license:
Reference information

Primary reference:

94412. Y. Yabumoto. 1987. Oligocene lamnid shark of the genus Carcharodon from Kitakyushi, Japan. Bulletin of the Kitakyushu Museum of Natural History 6:239-264 [M. Clapham/M. Clapham]