Figure 3 in Cranial skeletogenesis of one of the largest amphibians, Andrias japonicus, provides insight into ontogenetic adaptations for feeding in salamanders

Figure 3. Cranial skeletogenesis (dorsal view) in Andrias japonicus, Hynobius nebulosus, Pleurodeles waltl and Ambystoma mexicanum. Pink elements are bone. Blue elements are cartilage. Scale bars are 1 mm, except those for phase XIII An. japonicus and Am. mexicanum, which are 10 mm. Abbreviations: cl, columella; exo, exoccipital; fr, frontal; ma, maxilla; na, nasal; oc, otic capsule; opi, opisthotic, osph, orbitosphenoid; pa, parietal; pfr, prefrontal; pma, premaxilla; po, prootic; psph, parasphenoid; pt, pterygoid; q, quadrate; seth, sphenothmoid; sq, squamosal; vo, vomer.