Fig. 1
From: Ancestral mesodermal reorganization and evolution of the vertebrate head
Comparison of amphioxus and vertebrate early development. a Adult female amphioxus (Branchiostoma japonicum). b Adult female shark (Scyliorhinus torazame). c, d Comparison of dorsal mesoderm formation between amphioxus (c) and Xenopus (d) embryos. The notochord progenitor is labelled in pink, with the somite in green and head mesoderm in red. nc notochord, s somite, hm head mesoderm