Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

Journal of Paleontology

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by TANABE, K. Articles by IBA, Y. Search for Related Content GeoRef GeoRef Citation

TWO COLEOID JAWS FROM THE UPPER CRETACEOUS OF HOKKAIDO, JAPAN

¹ Department of Earth and Planetary Science, University of Tokyo, Tokyo 113-0033, Japan, <tanabe{at}eps.s.u-tokyo.ac.jp> and <iba@eps.s.u-tokyo.ac.jp>
² Nakagawa Museum of Natural History, Nakagawa Town, Hokkaido 098-2626, Japan, <nmhikida{at}coral.ocn.ne.jp>

Two isolated cephalopod jaws recovered from the middle Turonian of the Obira area and the Campanian of the Nakagawa area, Hokkaido, Japan, consist of short outer, and large and posteriorly elongated inner "chitinous" lamellae, with a sharply pointed rostrum in the outer lamella. These features are common with the upper jaws of Recent cephalopods. Comparison with the upper jaws of ammonoids and Recent cephalopods indicates that the two Cretaceous upper jaws are attributed to the Coleoidea other than the Octopodida. This assignment is also suggested by the cladistic analysis of the Nakagawa specimen compared with five upper jaw characters on 22 Recent cephalopod species. The Obira specimen differs from the Nakagawa specimen in having a much smaller jaw and a larger jaw angle, but its order-level assignment could not be determined because of imperfect preservation. The Nakagawa specimen shares several common features with the upper jaws of Recent Oegopsina; thus we assigned its higher systematic position to this suborder. Based on the extremely large upper jaw (97 mm maximum length), a new genus and species (Yezoteuthis giganteus) is proposed. This new taxon would have been as large as the modern giant squid Architeuthis, which commonly exceeds more than 5 m in body length. Our study postulates that studies of jaws are important to reconstruct the phylogeny of the Coleoidea.

This article has been cited by other articles:

				K. Tanabe, P. Trask, R. Ross, and Y. Hikida Late Cretaceous Octobrachiate Coleoid Lower Jaws from the North Pacific Regions Journal of Paleontology, March 1, 2008; 82(2): 398 - 408. [Abstract] [Full Text] [PDF]