FIGURE 4 in A new multi-faceted framework for deciphering diplodocid ontogeny

FIGURE 4. Presence of the Postparietal Aperture within Diplodocidea (indicated by red arrows). 1-4, Diplodocid specimens with the Postparietal Aperture: 1, Suuwassea (ANS 21122); 2, Galeamopus (SMA 0011); 3, Apatosaurus sp. (BYU 17096) (Balanoff, et al., 2010); 4, Kaatedocus (SMA 0004). Note 1 and 3 are dorsal views while 2 and 4 are posterior views. 5-6, Diplodocid skulls illustrating the presence of the Postparietal Aperture in immature individuals (5- image courtesy of the Science Museum of Minnesota), and its absence in mature individuals (6). For 5, from left to right: Kaatedocus (SMA 0004), Diplodocus sp. (SMM P. 84.15.3), Apatosaurus sp. (MOR 700), Galeamopus (SMA 0011; this skull is partially damaged, so the morphology of the foramen may be distorted), Suuwassea (ANS 21122), and Diplodocus sp. (MOR 592). For 6, note that the Diplodocus and Apatosaurus skulls are stylized renderings based on multiple specimens (from Whitlock [2011b]; Diplodocus sp. to scale of USNM 2672, and Apatosaurus louisae to CM 11162). Skulls in 5 and 6 to scale.