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1 April 2013 A New Species of Gaudryceras (Ammonoidea, Gaudryceratidae) from the Lowest Maastrichtian of Hokkaido, Japan and Its Biostratigraphic Implications
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Abstract

Gaudryceras hobetsense sp. nov. is described from the Nostoceras hetonaiense Zone (= lowest Maastrichtian) of the Hobetsu area, south-central Hokkaido, Northern Japan. Its shell is characterized by fine lirae on early whorls, distant rounded or flat-topped, narrow band-like ribs on middle and later whorls, and frequent collar-like ribs on later whorls. The occurrence of this new species strongly suggests the presence of lowest Maastrichtian strata in southern Alaska, and sheds light on the age delineation of the chronologically poorly defined beds in northern and eastern Hokkaido.

© by the Palaeontological Society of Japan
Yasunari Shigeta and Tomohiro Nishimura "A New Species of Gaudryceras (Ammonoidea, Gaudryceratidae) from the Lowest Maastrichtian of Hokkaido, Japan and Its Biostratigraphic Implications," Paleontological Research 17(1), 47-57, (1 April 2013). https://doi.org/10.2517/1342-8144-17.1.47
Received: 11 May 2012; Accepted: 1 August 2012; Published: 1 April 2013
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