Detailed analysis of the early evolutionary stage of Globigerina bulloides in Middle Miocene calcareous nannoplankton zones NN5 and NN6 shows no preference for sinistral or dextral coiling patterns despite seawater temperature variations (as inferred from stable isotope analyses of foraminifer shells). Accordingly, coiling direction was proportional or biased to sinistral.
- Received May 14, 2002.
- Accepted May 10, 2003.
- © 2003 The Micropalaeontological Society