Journal cover Journal topic
Journal of Micropalaeontology An open-access journal of The Micropalaeontological Society
J. Micropalaeontol., 36, 174-182, 2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
31 Mar 2017
Effect of gross morphology on modern planktonic foraminiferal test strength under compression
Janet E. Burke and Pincelli M. Hull Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT 06511, USA
Keywords: planktonic foraminifera, morphology, predation, pelagic ecology, iterative evolution Abstract. Planktonic foraminifera are a source of important geochemical, palaeoceanographic, and palaeontological data. However, many aspects of their ecology remain poorly understood, including whether or not gross morphology has an ecological function. Here, we measure the force needed to crush multiple planktonic foraminiferal morphotypes from modern core top and tow samples. We find significant differences in the resistance of different morphotypes to compressional force. Three species, Globorotalia tumida (biconvex, keeled), Menardella menardii (discoidal, keeled), Truncorotalia truncatulinoides (conical, keeled), require on average 59% more force (1.07 v. 0.47 N) to crush than the least resistant species (Orbulina universa and Trilobatus sacculifer) in core-top samples. Towed samples of pre-gametogenic individuals also show significant differences of the same magnitude (0.693 v. 0.53 N) between the conical (T. truncatulinoides) and globular/ spherical morphologies (Globoconella inflata and O. universa). We hypothesize that the greater compressional strength of certain shapes confers a fitness advantage against predators and could contribute to the repeated, convergent evolution of keeled, conical and bi-convex forms in planktonic foraminifer lineages.

Citation: Burke, J. E. and Hull, P. M.: Effect of gross morphology on modern planktonic foraminiferal test strength under compression, J. Micropalaeontol., 36, 174-182,, 2017.
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