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TitreThe ammonoid Desmoceras in the Upper Albian (Lower Cretaceous) of Japan
AuteurKawabe, F; Haggart, J W
SourceJournal of Paleontology vol. 77, no. 2, 2003 p. 314-322,
Séries alt.Commission géologique du Canada, Contributions aux publications extérieures 2001156
ÉditeurCambridge University Press (CUP)
Documentpublication en série
Mediapapier; en ligne; numérique
Lat/Long OENS 141.8667 142.2333 43.2000 43.0000
Lat/Long OENS 134.4833 134.4833 33.9500 33.9000
Sujetsbiomes; biostratigraphie; biogéographie; organismes marins; bassins; roches clastiques; mudstones; grès; paléontologie; sédimentologie; Crétacé
Illustrationsphotographs; stratigraphic columns; photographs; graphs; tables
Diffusé2016 05 20
Résumé(disponible en anglais seulement)
The Upper Albian Desmoceras species of Japan are described, based on material from the Yezo Supergroup in Hokkaido, north Japan, and from the Fujikawa Formation in Shikoku, southwest Japan. Based on comparative analysis of morphologic variation and shell growth of relevant specimens, we assign the present material to two species: Desmoceras (Desmoceras) latidorsatum (Michelin, 1838) and Desmoceras (Pseudouhligella) poronaicum Yabe, 1904. Japanese examples of the latter species have been previously referred to ''Desmoceras (Pseudouhligella) dawsoni,'' a Canadian species present on Queen Charlotte Islands, British Columbia, but not represented in the Japanese Islands. Desmoceras (Pseudouhligella) poronaicum is also known from British Columbia. The subgenus Pseudouhligella presumably originated in the eastern Pacific during the Late Albian and subsequently migrated to the western Pacific during latest Albian to earliest Cenomanian time. Desmoceras (D.) latidorsatum is a Tethyan form; its presence in the Upper Albian of the North Pacific probably reflects a northward excursion of warm-water currents from the tropical region during Late Albian time.