Fig. 4.

Phylogeny for the Globigerina lineage as per Aze et al. (24). Taxa are grouped in the same lineage based on overlap in the frequency distributions of morphotypes (24), but three lines of evidence indicate that Globigerina bulloides and Globigerina falconensis are reproductively isolated, and therefore independently evolving taxa: SSU rDNA genetic divergence is 22.9% (34), habitat preferences differ (62), only G. falconensis has symbionts (63). (Scale bars in gray, 100 µm for Globigerina praebulloides and Globigerina umbilicata and 50 µm for G. bulloides and G. falconensis.) Pt, Pleistocene. [G. praebulloides image reprinted from ref. 64, Copyright (2004), with permission from Elsevier. G bulloides image reprinted with permission from ref. 65. G. umbilicata image reprinted from ref. 66, Copyright (2003), with permission from Elsevier. G. falconensis image reprinted with permission from ref. 67.]