Figure S1: Changes in coiling and initial chamber size through time

(A) Diversity from the early Emsian to the late Eifelian with proportion of forms with openly coiled adult whorls and umbilical window (open + enclosed). The embryonic and post-embryonic whorls of representative taxa are shown of each category are shown (respectively Erbenoceras, Mimagoniatites and Agoniatites). (B-C) Boxplots showing the distribution and fluctuations of initial chamber size (initial chamber diameter PD in mm) within the Devonian (B) and in the Phanerozoic (C) from the Devonian until the Cretaceous (whiskers = minima and maxima excluding outliers, boxes = middle two quartiles, horizontal stripe = median value, dots = outliers). Abbreviations: E. Dev = Early Devonian, M. Dev. = Middle Devonian, L. Dev. = Late Devonian, Dev. = Devonian, Carb. = Carboniferous, Perm. = Permian, Tria = Triassic, Jura. = Jurassic, Cret. = Cretaceous. Histograms were produced in the freely available statistical environment R (http://www.r-project.org/).

(A) 埃姆斯期早期至艾菲尔期晚期的类群多样性，以及具开放式成年壳旋与脐窗的类群占比（涵盖开放式与封闭式类型）。各分类类群的代表性类群的胚胎壳旋与胚后壳旋均已展示（依次为Erbenoceras、Mimagoniatites与Agoniatites）。(B-C) 箱线图展示了泥盆纪内部（B）及显生宙（C，时间跨度为泥盆纪至白垩纪）的初始气室尺寸（以毫米为单位的初始气室直径PD）的分布与波动特征。其中，须线代表剔除异常值后的最小值与最大值，箱体对应上下四分位数区间，横向标线代表中位数，圆点代表异常值。缩写说明：E. Dev为早泥盆世，M. Dev.为中泥盆世，L. Dev.为晚泥盆世，Dev.为泥盆纪，Carb.为石炭纪，Perm.为二叠纪，Tria为三叠纪，Jura.为侏罗纪，Cret.为白垩纪。本研究中的直方图均在开源统计编程环境R（http://www.r-project.org/）中绘制完成。