Molding and carving cell surfaces: The joke of a fold and the origin and evolution of feathers

Abstract

Cornification of cells in the epidermis of amniotes is different from that of derivatives such as scales, feathers, hairs, horns, nails, claws etc. (Maderson, 1985; Wu et al., 2004). Eventually epidermal layers detach (shedding or molting) from the remaining epidermis. Molting occurs along intra epidermal regions made by cells with different types of keratinization, and this interface often produces microornamentation of variable shapes. © 2009 Springer Science+Business Media B.V.