Fig. 12

Contoured frequency plots of spiral height (δX) versus axial length (δY) for G. menardii in keel view at Hole 925B from 0 to 7.96 Ma. The contour intervals (int) are in specimens per grid cell as indicated in the upper right corner of each diagram. The n indicates the number of specimens represented in each diagram. The diagonal line in each diagram was suggested in Knappertsbusch (2007) to distinguish between morphotype alpha and morphotype beta in sediments younger than about 0.22 Ma. In that study morphotype alpha was tentatively associated with G. menardii menardii and morphotype beta with G. menardii cultrata including G. fimbriata. The same separation line is redrawn here for comparison reasons. Vertical gray auxiliary lines at δX = 300 μm help to compare the secondary frequency modes between samples. The grid cell size is ΔδX = 50 μm and ΔδY = 100 μm. Measurements of δX and δY from individuals can be read from Table 4a in the electronic supplementary materials