New species of the genus Douvilleiceras (ammonoid) from the Lower Cretaceous Yezo Group in Hokkaido

Masao FUTAKAMI

doi:10.2183/pjab.79B.237

Proceedings of the Japan Academy, Series B

Online ISSN : 1349-2896
Print ISSN : 0386-2208
ISSN-L : 0386-2208

Original Papers

New species of the genus Douvilleiceras (ammonoid) from the Lower Cretaceous Yezo Group in Hokkaido

Masao FUTAKAMI

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Keywords: Ammonite, Douvilleiceras, Yezo Group, Hokkaido, Lower Albian (Lower Cretaceous)

JOURNAL FREE ACCESS

2003 Volume 79B Issue 8 Pages 237-241

DOI https://doi.org/10.2183/pjab.79B.237

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Abstract

Two new species of douvilleiceratid ammonite, Douvilleiceras compressum and D. kawashitai, are described from the Lower Cretaceous Yezo Group in the Pombetsu Valley of Hokkaido. D. compressum is unique in its compressed whorl section in the genus. D. kawashitai is fairly similar to D. orbignyi Hyatt in its morphological characters, but the former is distinctly characterized by six rows of tubercles, instead of seven for the latter, on each side of the whorl.

(Communicated by Tatsuro MATSUMOTO, M. J. A., Oct. 14, 2003)

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