HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by AMANO, K. Search for Related Content GeoRef GeoRef Citation

TEMPORAL PATTERN OF NATICID PREDATION ON GLYCYMERIS YESSOENSIS (SOWERBY) DURING THE LATE CENOZOIC IN JAPAN

¹ Department of Geoscience, Joetsu University of Education, 1 Yamayashiki, Joetsu City, Niigata Prefecture, 943-8512, Japan amano{at}juen.ac.jp

No temporal trend in the intensity of drilling by naticids on Glycymeris yessoensis can be recognized during the late Cenozoic. Drilling sites shifted from the umbo to the center of the valve during the late Cenozoic. This shift might reflect the change of predators from Glossaulax in the Miocene to Cryptonatica or Euspira in the Pleistocene. Borehole sites in the middle Pleistocene were more stereotyped than in the early Pleistocene population despite the same predators. Edge drilling, which is a faster drilling method, first appeared in the population showing high drilling intensities in the early Pleistocene. Because a prediction of the hypothesis of escalation is that changes in predators' behavior developed through time, these changes in drilling location may be the results of escalation. In contrast with the stereotypic trend of borehole sites, correlation coefficients of predator-prey size decreased from the early to the middle Pleistocene.