Fig. 1.

Phylogenetic framework for the discussion provided in the present paper and the comparison between the head and neck muscles of the genera listed in Tables 1–4 and shown in Figs 3–17, based on Shoshani et al. (1996), Kardong (2002), Sargis (2002a,b, 2004), Dawkins (2004), Kemp (2005), Marivaux et al. (2006), Diogo (2007), Janeka et al. (2007), and Silcox et al. (2007). N.B. When we use the term reptiles we refer to the group including taxa such as turtles, tuataras, lizards, snakes, crocodiles, and Aves, which, despite some controversy, continues to be considered a monophyletic taxon by most taxonomists and in most general textbooks (e.g. Kardong, 2002; Dawkins, 2004; Diogo, 2007); the Primates, Dermoptera (including colugos or ‘flying lemurs’) and Scandentia (including tree-shrews) are placed in an unresolved trichotomy, because the relationships between these three groups remains mainly unresolved (some authors continuing to group colugos with tree-shrews, others group tree-shrews with primates, and yet others group colugos with primates: e.g. Sargis, 2002a,b, 2004; Dawkins, 2004; Marivaux et al. 2006; Janeka et al. 2007; Silcox et al. 2007).