Ethmoidal region of cross-age series of the night monkey (Aotus nancymaae) in coronal view. A–D Histological serial sections of a newborn (Aotus108). Shown are the first and second ethmoturbinal (ET I, II) (A, C), and enlarged views of each (B, D); note some cartilage remains (*) in both turbinals. No ET III is visible in any newborn in our sample. E–G Coronal µCT slices in rostral view in that the ETs are highlighted on the left side of the nasal fossa. ET III is visible as a bony ridge in a 14-days-old A. nancymaae (Aotus104) (E), and is more elongated in an older infant (Aotus102; with full deciduous eruption) (F), and in an adult (Aotus1) (G). Abbreviations: LA, lamina anterior of ET I; LT, lamina terminalis; MT, maxilloturbinal; SF, sinus frontalis; SM, sinus maxillaris. Scale bars: 1 mm (A, C); 0.1 mm (B, D); 0.5 mm (E–G).