Fig. 5
Means of cross-sectional area in keel view (in mm2) through time (in Myrs) at Hole 925B for G. menardii (a), G. limbata (b), G. multicamerata (c), and the comparison of the three groups (d). Squares G. menardii (including G. menardii cultrata, G. menardii menardii, G. gibberula, transitional forms between G. menardii–G. exilis, G. menardii–G. pseudomiocenica, and G. menardii–limbata), circles G. limbata; triangles G. multicamerata. Open symbols are means. In a–c horizontal bars indicate the range from the lower to upper quartiles of the samples, and filled black squares represent sample medians. Left and right gray lines are sample minima and maxima, respectively. Dashed lines indicate 10 and 90 % sample percentiles. In a–c linear regression lines are drawn through sample means with equations indicated, and values of r 2 are linear regression coefficients. In case of G. limbata the single specimens of the five uppermost samples (i.e. at 1.95, 1.65, 0.86, 0.33 and at 0.20 Ma in b and d) were omitted for the calculation of the regression line because reworking cannot be excluded for these specimens, see explanation in the text. The same applies to the following Figs. 6, 7, 8, 9, 10 and 11. In d sample means are re-plotted together for G. menardii, G. limbata and G. multicamerata for easier comparison, with horizontal bars indicating ±95 % confidence intervals around the means per group. Gray shaded horizontal stripes represent intervals barren in menardiform globorotalids (0.51, 0.61, 1.12, 1.47, 1.8, 2.057, 2.154, 2.24, 2.266, and 2.91 Ma. Information for horizons at 0.61, 2.24 and 2.91 Ma are from Chaisson and Pearson (1997). Individual measurements are given in Table 4a–c. Statistics can be read from Table 5a–c. Table 6 provides explanations to these data. Tables 4a–c, 5a–c, and 6 can all be found in the electronic supplementary material