Embryonic keratinization in vertebrates in relation to land colonization

The embryogenesis and cytology of the epidermis in different vertebrates is variable in relation to the formation of a stratum corneum of different complexity. The latter process was essential for land colonization during vertebrate evolution and produced an efficient barrier in amniotes. Keratinocytes are made of cross‐linked keratins associated with specific proteins and lipids that are produced at advanced stages of embryogenesis when the...