Yamanouchi: Burdigalian, Japan

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Osteichthyes - Crotalidae
Trimeresurus sp. Lacépède 1804
Holman and Tanimoto 2004 1 specimen
Osteichthyes - Cetacea
Kimura and Hasegawa 2004 1 specimen
1 specimen
Osteichthyes - Cetacea - Kentriodontidae
Okazaki 1976 1 specimen
Tanaka et al. 2026
Malacostraca - Decapoda - Macrophthalmidae
Karasawa 1990
Malacostraca - Decapoda - Carcinidae
Karasawa 1990
Karasawa 1990
Karasawa 1990
Malacostraca - Decapoda - Goneplacidae
Carcinoplax antiqua (Ristori 1889)
Karasawa 1990
Malacostraca - Decapoda - Cancridae
Karasawa 1990
Malacostraca - Decapoda - Hexapodidae
Paeduma sp. Rathbun 1897
Karasawa 1990
see common names

Geography
Country:Japan State/province:Gifu
Coordinates: 35.4° North, 137.2° East (view map)
Paleocoordinates:35.3° North, 134.5° East (Wright 2013)
Basis of coordinate:stated in text
Time
Period: Neogene Epoch: Miocene
Stage: Burdigalian 10 m.y. bin: Cenozoic 5
Key time interval: Burdigalian Foram zone:  N7 to N8
Age range of interval: 20.45 - 15.98 m.y. ago
Age estimate: 17.5 to 16.0 Ma (other)
Stratigraphy
Geological group:Mizunami Formation:Akeyo Member:Yamanouchi
Stratigraphic resolution:member
Stratigraphy comments: upper part of Zone N7 and lower part of N8 of Blow (1969)
Planktonic foraminiferal data place the Hiramatsu Member of the Awa Group in zone N7 [132, 133], ranging from 17.5–16.4 Ma [20, 54]; and the Yamanouchi Member of the Ayeko Formation in the upper part of zone N7 and the lower part of zone N8 [134], with zone N8 ranging from 16.4–15.1 Ma [20, 54]. Fission-track dating of a sample from the base of the Yamanouchi Member indicates an age of 17.3 ± 1.4 Ma [135]. Although the termination of zone N8 at 15.1 Ma could imply a partially Langhian range, we here constrain the age of I. laticephalus to the late Burdigalian (17.5–16.0 Ma) based on (i) the confirmed Burdigalian age of MFM 28501; (ii) the fact that the lower boundary of the Yamanouchi Member predates the Burdigalian/Langhian boundary by as much as 1 Ma, or possibly more; and (iii) the fact that the Yamanouchi Member was only correlated with the lower part of zone N8. (Marx & Fordyce, 2015)
Lithology and environment
Primary lithology: siltstone
Includes fossils?Y
Environment:shallow subtidal indet.
Geology comments: nearshore, silty bottom, influenced by subtropical water currents
Taphonomy
Modes of preservation:body,original phosphate,replaced with phosphate
Size of fossils:macrofossils
Collection methods and comments
Collection methods:surface (float),surface (in situ),field collection
Reason for describing collection:taxonomic analysis
Metadata
Database number:46950
Authorizer:M. Uhen, J. Head Enterer:M. Uhen, J. Head
Modifier:M. Uhen Research group:vertebrate
Created:2005-01-27 07:23:53 Last modified:2026-03-18 10:05:22
Access level:the public Released:2005-01-27 07:23:53
Creative Commons license:CC0
Reference information

Primary reference:
12471. T. Kimura and T. Ozawa. 2002. A new cetothere (Cetacea: Mysticeti) from the early Miocene of Japan. Journal of Vertebrate Paleontology 22(3):684-702 [M. Uhen/M. Uhen/M. Uhen]

Secondary references:

12940 J. A. Holman and M. Tanimoto. 2004. cf. Trimeresurus Lacépède (Reptilia: Squamata: Viperidae: Crotalinae) from the late Early Miocene of Japan. Acta Zoologica Cracoviensia 47(1):1-7 [J. Head/J. Head/J. Head]
71608 H. Karasawa. 1990. Decapod crustaceans from the Miocene Mizunami Group, central Japan. Part 2. Section Oxyrhyncha, Cancridea and Brachyrhyncha. Bulletin of the Mizunami Fossil Museum 17:1-33 [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]
55050 F. G. Marx and R. E. Fordyce. 2015. Baleen boom and bust: a synthesis of mysticete phylogeny, diversity and disparity. Royal Society Open Science 2:140434 [M. Uhen/M. Uhen]
13631 Y. Okazaki. 1976. Miocene long-snouted porpoises from the Mizunami Group, Central Japan. Bulletin of the Mizunami Fossil Musuem 3:25-39 [M. Uhen/M. Uhen/M. Uhen]
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]