“…The cranial innervation system provides sensory cues to the brain while the carotid circulation system provides blood to sensory and other organs. Therefore, differences in cranial blood supply and innervation can give clues about the sensory capacities of animals (e.g., mechanoreception; Dehnhardt & Mauck, 2008;Muchlinski, 2008;George & Holliday, 2013), their physiology (e.g., thermoregulation; Porter & Witmer, 2015;Yu, Ashwell & Shulruf, 2019), the presence and type of cranial soft tissues in fossils (Benoit et al, 2018), as well as the evolution of these features along stem-lineages (Benoit, Manger & Rubidge, 2016;Benoit et al, 2018;Joyce, Volpato & Rollot, 2018;Evers, Barrett & Benson, 2019). Despite showing specific adaptations that often relate to ecological specializations, both the nervous and carotid systems are relatively conservative between major amniote clades in terms of their morphological evolution (Kardong, 1998;Müller, Sterli & Anquetin, 2011) and can therefore be used to examine variational patterns along deep diverging lineages, possibly providing phylogenetic character support for specific divergences.…”