Also known as Hobetsu-cho, Tosanosawa river

Where: Hokkaido, Japan (42.8° N, 142.1° E: paleocoordinates 52.2° N, 136.3° E)

• coordinate estimated from map

• small collection-level geographic resolution

When: Cenomanian (100.5 - 93.9 Ma)

• Yezo supergroup (Late Cretaceous) exposed at Tosano-sawa River, Hobetsu-cho, Hokkaido Prefecture, North Japan (Fig. 1; Matsumoto and Toshimitsu, 1991). The geologic age of HMG 1056 was determined by radiolarian fossils extracted from associated matrix of calcareous siltstone (Kito et al., 1998). The well preserved assemblage, including Pseudodictyomitra pseudomacrocephala, Xitus mclaughlini, Torculum coronatum, Holocryptocanium cf. tuberculatum, H. barbui, Patellula spp., and Pyramispongia sp., indicates a Cenomanian age (Kito et al., 1998). This age is concordant with the age determined by ammonites such as Austiniceras cf. austeni (Sharpe) collected from a nearby locality at Tosanosawa River (Matsumoto and Toshimitsu, 1991).

• bed-level stratigraphic resolution

Environment/lithology: terrestrial; concretionary, calcareous siltstone

Size class: macrofossils

Collected by Mr. Toshimitsu Abe in 1977

Collection methods: surface (float), surface (in situ), mechanical, acetic,

• HMG collection, Hobetsu Museum, Hobetsu, Hokkaido Prefecture, Japan

Primary reference: R. Hirayama, K. Sakurai, T. Chitoku, G. Kawakami, and N. Kito. 2001. Anomalochelys angulata, an unusual land turtle of family Nanhsiungchelyidae (superfamily Trionychoidea; order Testudines) from the Upper Cretaceous of Hokkaido, North Japan. Russian Journal of Herpetology 8(2):127-138 [R. Benson/R. Benson/R. Benson]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 129339: authorized by Roger Benson, entered by Roger Benson on 23.06.2012

Creative Commons license: CC BY (attribution)