Fig. 11
From: Analysis of septal spacing and septal crowding in Devonian and Carboniferous ammonoids
Ontogenetic trajectories of septal distances in six representatives of the Late Tournaisian Imitoceras. Respective phragmocone diameters (in mm) in the bottom boxes. A–C Imitoceras dimideum Korn, Bockwinkel & Ebbighausen, 2010a from Oued Temertasset. D–F Imitoceras ixion (Hall, 1860) from Rockford (Indiana) (11E after Miller et al., 1957)