二枚貝類の体サイズ変化と大量絶滅の要因に関する一仮説

概要

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A number of studies concerning shell-size changes of bivalves in time and space are reviewed from an ecological viewpoint. Although various environmental factors may influence the body size of organisms, recent knowledge of deep-sea and submarine cave faunas indicates that food supply is of prime importance as a factor controlling the adult size and adaptive strategy of bivalves. Significant shell-size reduction of bivalves seems to have occurred at the same time with P/Tr and K/T mass extinctions, probably because large-sized species (or groups) were more or less selectively eliminated. I present here a hypothesis that oligotrophic conditions (especially reduction of primary production on a global scale) are responsible for these mass extinctions, even if such a condition may arise from various geologic and astronomical events.
日本古生物学会の論文
1997-06-30