Hostname: page-component-8448b6f56d-cfpbc Total loading time: 0 Render date: 2024-04-16T07:15:23.673Z Has data issue: false hasContentIssue false

Life positions of fossil naticid opercula (Mollusca: Gastropoda)

Published online by Cambridge University Press:  14 July 2015

Ryuichi Majima*
Affiliation:
Institute of Geoscience, University of Tsukuba, Ibaraki 305, Japan

Abstract

Two life positions of fossil naticid opercula are recognized in Pliocene deposits of Hokkaido, northern Japan. In one position, the operculum seals the aperture. In the other position, the operculum is pressed against the shell base adjacent to the aperture. The death position of the head-foot mass can be reconstructed from the two opercular positions, which coincide, respectively, to naticids that died with the head-foot mass retracted into the shell, and those that died with it entirely extended from the shell.

Type
Research Article
Copyright
Copyright © The Paleontological Society 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Graham, J. 1965. Association of operculum with Magnatica planispira (Suter). New Zealand Journal of Geology and Geophysics, 8(5):853CrossRefGoogle Scholar
Jenkins, H. M. 1863. On some Tertiary Mollusca from Mount Sela, in the Island of Java. Quaternary Journal of Geological Society of London, 20:4573.CrossRefGoogle Scholar
Majima, R. 1984. Observations on occurrences of Japanese Neogene naticids (Gastropoda) bearing calcareous opercula. Transactions and Proceedings of the Palaeontological Society of Japan, new series, (134):361373.Google Scholar
Marincovich, L. Jr. 1977. Cenozoic Naticidae (Mollusca: Gastropoda) of the northeastern Pacific. Bulletins of American Paleontology, 70(294):169453.Google Scholar
Pavia, G. 1980. Gli opercoli calcarei delle Naticidae (Mollusca, Gastropoda) nel Pliocene Norditaliano. Bollettino Malacologico, 16(7–8):225275.Google Scholar
Schileyko, A. A. 1977. Data on the anatomy of naticoidea and problems of taxonomy of the subfamily (Mollusca: Mesogastropoda). Transactions of the Institute of Oceanology, 108:7797. (In Russian with English summary.)Google Scholar
Woodring, W. P. 1957. Geology and paleontology of the Canal Zone and adjacent parts of Panama. U.S. Geological Survey Professional Paper 306-A, 145 p.Google Scholar