This suture is considered homologous to the intracranial joint in coelacanths (with the addition of a neoformation, the posterior parietal intercalated between the anterior parietal and the postparietal)42, which indeed shows a craniosynostosis in Foreyia and Rieppelia. The Shh glycoprotein, secreted from the zone of polarising activity (ZPA) in tetrapods and teleosts37,44,46, and expressed in the dorsal fin of teleosts46, plays a role in branching morphogenesis mechanism in the zebrafish44. This evidence concerns the gene SHH and craniosynostosis.