Unravelling the evolution of extraordinary long-range planktonic foraminifera species based on image processing analysis

Roni Tadir, Nimrod Shneor, Sigal Abramovich, Danna Titelboim, Sarit Ashckenazi-Polivoda

Research output: Contribution to journalArticlepeer-review


The recent growing interest in Late Cretaceous biserial planktonic foraminifera (heterohelicids) has greatly enhanced their use as paleoceanographic and biostratigraphic markers. Pseudotextularia nuttalli, one of the most common cosmopolitan planktonic foraminifera, has an exceptionally long evolutionary range (Turonian-Maastrichtian). The image processing procedure we developed in this study enabled us to document changes in the growth pattern of Ps. nuttalli over time and between different oceanic provinces, and to identify possible speciation events within this lineage. The analysis was complemented by morphometric measurements of the penultimate chamber and test. The morphometric analyses do not indicate an early speciation event within this lineage, and thus, do not support splitting to Planoheterohelix praenuttalli (Turonian-Coniacian) and Pseudotextularia nuttalli (Coniacian-Maastrichtian). Our results indicate a gradual phyletic increase in mean test size from the Santonian through the Maastrichtian, along with increasing morphological diversification. This trend seems to coincide with the global cooling that culminated in the Late Cretaceous. Comparing between Ps. nuttalli from different oceanic provinces reveals that the Southern Tethys specimens are significantly less developed than their counterparts from the two tropical oceanic localities. This adaptive responsiveness suggests a negative correlation between test size and high productivity conditions in the upper water column. The case of Ps. nuttalli lineage exemplifies how extraordinary long-range species (>30 My) can evolutionarily change over time from “primitive” to “developed” forms, without showing a morphological gap. Such species may also show adaptive morphological diversification in response to different environments and, thus, are valuable for palaeoceanographic and paleoecologic reconstructions.

Original languageEnglish
Article number102015
JournalMarine Micropaleontology
StatePublished - 1 Jun 2021


  • Growth pattern
  • Late Cretaceous
  • Long-range species
  • Morphometric analyses
  • Phyletic trends
  • Planktonic foraminifera

ASJC Scopus subject areas

  • Oceanography
  • Paleontology


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