Where: Hokkaido, Japan (42.8° N, 142.2° E: paleocoordinates 46.9° N, 131.5° E)
• coordinate estimated from map
• small collection-level geographic resolution
When: Lower sandy Siltstone Member (Hakobuchi Formation), Early/Lower Maastrichtian (70.6 - 66.0 Ma)
• The middle portion of the lower sandy siltstone formation consists of dark gray sandy siltstone, bearing marine invertebrates such as Inoceramus (Cataceramus) shikotanensis, Pachydiscus (Neodesmoceras) japonicus and Neophylloceras hetonaiensis which indicate an early lower Maastrichtian age.
• bed-level stratigraphic resolution
Environment/lithology: marine; concretionary, gray, sandy, calcareous siltstone
Size class: macrofossils
Collected by S. Suzuki, S. Toshimitsu, T. Chitoku in 1981-1989
Collection methods: surface (float), surface (in situ), mechanical, acetic,
• Collection of Hobetsu Museum at Hobetsu-cho, Hokkaido, Japan
Primary reference: R. Hirayama and T. Chitoku. 1996. Family Dermochelyidae (superfamily Chelonioidea) from the Upper Cretaceous of north Japan. Transactions and Proceedings of the Palaeontological Society of Japan. New series 184:597-622 [R. Benson/R. Benson]more details
Purpose of describing collection: taxonomic analysis
PaleoDB collection 129272: authorized by Roger Benson, entered by Roger Benson on 23.06.2012
Creative Commons license: CC BY (attribution)
Taxonomic list
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Mesodermochelys undulatus Hirayama and Chitoku 1996 leatherback HMG 8, thoracic and sacral vertebrae, hind limbs, posterior portion of shell; HMG 363, prootic, caudal vertebrae, hind limbs and peripherals; HMG 365, pectoral girdles and anterior portion of plastron; HMG 369, lower jaw, hyoids, almost complete cervicals, first thoracic and caudal vertebrae, appendicular skeletons, anterior portion of carapace, and good plastron
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