African clawed frog
Epibolic movements have been conserved in vertebrates. Though most work on epiboly has been done in fish, there is also a body of work concerning epiboly in the African clawed frog, "Xenopus laevis". Comparisons of epiboly in amniotes, teleosts and "X. laevis" show that the key movement of epiboly in the fish and frog is radial intercalation while in amniotes it would appear to be cell division in the plane of the epithelium. All groups undergo cell shape changes such as the characteristic flattening of cells to increase surface area.