Chenaibo coastal cliff plesiosaur, Wakkanai area: Cenomanian, Japan

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Osteichthyes - Plesiosauria - Elasmosauridae
1 specimen
Articulated postcranial skeleton in a concretion
see common names

Geography
Country:Japan
Coordinates: 45.4° North, 142.0° East (view map)
Paleocoordinates:51.7° North, 146.5° East (Wright 2013)
Basis of coordinate:based on nearby landmark
Altitude:19 meters
Geographic resolution:small collection
Time
Period: Cretaceous Epoch: Late Cretaceous
Stage: Cenomanian 10 m.y. bin: Cretaceous 5
*Period:Late/Upper Cretaceous *Epoch:Gallic
Key time interval: Cenomanian
Age range of interval: 100.5 - 93.9 m.y. ago
* legacy (obsolete) database fields
Stratigraphy
Geological group:Middle Yezo Formation:Chenaibo
Stratigraphic resolution:bed
Stratigraphy comments: not indicated what level sample is taken from, but from same bed as other samples from this reference
The planktonic and benthic foraminiferans are assignable to Rotalipora and Textularia hikagezawaensis Range-zones (of Maiya and Takayanagi, 1977), respectively, and indicate the Cenomanian; and the radiolarian species are assignable to the Diacanthocapsa euganea-Thanarla elegantissima Zone (of Taketani, 1982), which indicates Upper Albian to Cenomanian. Thus we conclude the hosiron of the plesiosaur to be Cenomanian.
Lithology and environment
Primary lithology:concretionary calcareous "shale"
Includes fossils?Y
Lithology description: The bones are embedded in a large calcareous nodule, which came from a shale bed containing a few plant fragments
Environment:marine indet.
Taphonomy
Modes of preservation:body,concretion
Size of fossils:macrofossils
Articulated whole bodies:some
Collection methods and comments
Collection excludes:difficult macrofossils
Collection methods:field collection
Reason for describing collection:taxonomic analysis
Metadata
Database number:28177
Authorizer:J. Alroy Enterer:E. Leckey
Modifier:R. Benson Research group:vertebrate
Created:2003-01-27 12:23:20 Last modified:2025-02-22 15:12:02
Access level:the public Released:2003-01-27 12:23:20
Creative Commons license:CC0
Reference information

Primary reference:

7701.5% 20860I. Obata, Y. Kawashita, S. Maiya, Y. Taketani, M. Futakami and T. Suzuki. 1989. An Upper Cretaceous plesiosaur (Family Elasmosauridae) from the Wakkanai area Hokkaido. Bulletin of the National Science Museum, Series C: Geology, Tokyo 15(1):25-31 [J. Alroy/R. Whatley/M. Carrano]