New records of coleoid cephalopod jaws from the Upper Cretaceous of Hokkaido, Japan, and their paleobiogeographic and evolutionary implications. (February 2017)

• Record Type: Journal Article
• Authors: Tanabe, Kazushige; Misaki, Akihiro; Hikida, Yoshinori; Nishimura, Tomohiro
• Is Part Of: Cretaceous research. Volume 70(2017)
• Page Start: 128
• Page End: 141
• Publication Date: 2017-02
• Subjects: Late Cretaceous -- Coleoidea -- Jaws -- Paleobiogeography -- Evolution -- North Pacific; Geology, Stratigraphic -- Cretaceous -- Periodicals; 551.77
• DOI: 10.1016/j.cretres.2016.10.009
• Languages: English
• ISSNs: 0195-6671

Abstract

Abstract: Seven coleoid jaws recovered from Santonian to lower Campanian (Upper Cretaceous) strata in Hokkaido, Japan were taxonomically studied. Based on the comparison with the jaws of modern and fossil coleoids, six of the seven jaw fossils are referred to the following two genera and three species, including one possible new species: Nanaimoteuthis jeletzkyi and N. yokotai of the order Vampyromorpha, and Paleocirroteuthis sp. nov. (?) of the order Cirroctopodida. The other single lower jaw is seemingly similar to those of modern octopods and teuthids with respect to the shape of the inner lamella, but its order-level assignment could not be determined because of its imperfect preservation. N. jeletzkyi has been described in the Upper Cretaceous fore-arc basin deposits in Hokkaido (Yezo Group) and Vancouver Island, Canada (Nanaimo Group), whereas N. yokotai occurs only in the Yezo Group. These findings, complemented by previous reports of coleoid jaws, gladii, and phragmocones from the Yezo and Nanaimo Groups, demonstrate that a highly diversified, non-belemnitid coleoid fauna including large teuthids had already appeared during the post-Albian Late Cretaceous, in the North Pacific region. Highlights: Seven Late Cretaceous coleoid jaws from Hokkaido, Japan were taxonomically studied. They are assigned to 2 genera and 3 species of Vampyromorpha and Cirrocotopodida. Non-belemnitid coleoids existed in the Late Cretaceous North Pacific region.