Morphometric variability in the extant coccolithophores: Implications for the fossil record

Abstract

This detailed quantitative study shows significant intraspecific morphologic variability in species within modern calcareous nannoplankton communities. The link between depth of habitat and particular morphological components may indicate morphological adaptation and functionality. I use fine scale morphological characteristics to differentiate species variants or conversely, to identify polymorphism within species. Rhabdospheres and rhabdoliths of species within the family Rhabdosphaeraceae are analyzed as shallow photic zone proxies and reveal significant intra- and interspecific variability, whereas coccospheres and coccoliths of species in the deep photic zone show notably less variability in size and structure. The intra- and interspecific morphological variability that is noted with depth stratification is applicable to the fossil record in paleoceanographic reconstruction. I compare the extant species of the deep photic zone to the Miocene Minylitha convallis and find parallels that imply similar habitats (depth and stratification).%%%%