Seeking a better life in the plankton

Abstract

Foraminifers are single-celled, testate protists with a rich geologic record spanning at least 500 million years of Earth's most recent history. Their abundance, diversity, and diagnostic distribution patterns make them very useful to Earth scientists for purposes of relative age determination, correlation from one locality to another, and paleoenvironmental reconstructions. Benthic foraminifers occupy nearly every conceivable marine habitat ranging from coastal salt marshes and estuaries to marginal silled basins and deep-sea trenches. They range from pole to pole and are particularly diverse and abundant in shallow waters of the tropics. Planktic foraminifers have a shorter geologic history that begins ≈180 Ma in the late Early Jurassic. Traditional classification has assigned all of the planktic forms to a single suborder Globigerinina (1). Such a classification scheme implies a monophyletic origin for the planktic foraminifers, although many specialists have long suspected a polyphyletic origin from benthic ancestors.