Nakahara: Burdigalian, Japan

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Osteichthyes - Cetacea
Otsuka and Ota 2008
Otsuka and Ota 2008
Kimura et al. 2004 4 specimens
n. sp. Misspelled as Diocetus sp.
Otsuka and Ota 2008
Kimura et al. 2004 5 specimens
Otsuka and Ota 2008
Bivalvia - Cardiida - Cardiidae
Cardium sp. Linnaeus 1758
Otsuka and Ota 2008
Bivalvia - Adapedonta - Pharidae
Cultellus sp. Schumacher 1817
Otsuka and Ota 2008
Bivalvia - Venerida - Ungulinidae
Diplodonta sp. Bronn 1831
Otsuka and Ota 2008
see common names

Geography
Country:Japan State/province:Hiroshima County:Shobara
Coordinates: 34.9° North, 133.0° East (view map)
Paleocoordinates:34.5° North, 130.4° East (Wright 2013)
Basis of coordinate:estimated from map
Geographic resolution:local area
Time
Period: Neogene Epoch: Miocene
Stage: Burdigalian 10 m.y. bin: Cenozoic 5
Key time interval: Burdigalian
Age range of interval: 20.45 - 15.98 m.y. ago
Age estimate: 17 to 14.9 Ma (other)
Stratigraphy
Geological group:Bihoku Formation:Korematsu
Stratigraphic resolution:formation
Stratigraphy comments: The Korematsu Formation in the Shobara area underlies the Itabashi Formation, and together with latter forms the middle/upper portion of the Bihoku Group [114]. Calcareous nannoplankton correlates the Korematsu Formation and the lower part of the Itabashi Formation with the upper part of nannoplankton zone NN4 [114], suggesting a latest Burdigalian or early Langhian age with a minimum of 14.9 Ma [20, 54]. A further study [115] specifically correlated the Korematsu and Itabashi formations exposed along the stretch of the Saijyo River that yielded the whale fossils with the top of nannoplankton zone NN4, and the beginning of the “Mid-Neogene Climatic Optimum” (ca. 16–15 Ma [49, 116]). By contrast, diatom-based biostratigraphic data place the upper part of the Bihoku Group almost entirely in the late Burdigalian (17.0–16.0 Ma) [35, 36, 117, 118]. Together, these estimates amount to an age range of 17.0–14.9 Ma. (Marx & Fordyce, 2015)
Lithology and environment
Primary lithology: not reported
Includes fossils?Y
Environment:marine indet.
Taphonomy
Modes of preservation:body
Size of fossils:macrofossils
Collection methods and comments
Reason for describing collection:general faunal/floral analysis
Metadata
Also known as:Shobara City
Database number:278372
Authorizer:M. Uhen Enterer:M. Uhen
Modifier:M. Uhen Research group:vertebrate
Created:2026-03-17 10:24:35 Last modified:2026-03-17 11:08:11
Access level:the public Released:0000-00-00 00:00:00
Creative Commons license:
Reference information

Primary reference:
94329. Y. Tanaka, T. Yamaoka, H. Ohzawa and T. Kiyoshi. 2026. A short report of the first record of an Odontoceti (toothed whale) from the Korematsu Formation, Bihoku Group (latest Early to earliest Middle Miocene) in Japan. Paleontological Research 30(1389):17-27 [M. Uhen/M. Uhen]

Secondary references:

19082 T. Kimura, Y. Hasegawa, and J. Hinata. 2004. A middle Miocene Mysticeti from the Bessho Formation, Nagano Prefecture, central Japan. Bulletin of the Gunma Museum of Natural History 8:89-92 [M. Uhen/M. Uhen]
15356 T. Kimura and Y. Hasegawa. 2004. An outline of the Miocene cetotheres of Japan. Bulletin of the Gunma Museum of Natural History 8:79-88 [M. Uhen/M. Uhen]
27261 H. Otsuka and Y. Ota. 2008. Cetotheres from the early Middle Miocene Bihoku Group in Shobara District, Hiroshima Prefecture, West Japan. Miscellaneous Reports of the Hiwa Museum for Natural History 49(2):1-66 [M. Uhen/M. Uhen/M. Uhen]