A new cell type in the epidermis of zebrafish, and a new role for the hypodermis in pigmentation.

Zebrafish skin is composed of three layers, each of which contains distinct cell types. For example, the dermis (the middle layer) contains fibroblast cells, pre-scale forming cells and scale forming cells; the latter two cell types support the growth of scale plates which, when coated with a matrix that allows calcification, will become scales. Aman et al. demonstrate the presence of a previously unknown cell type (blue) in the epidermis (the top layer) which expressed genes necessary for enamel formation. Aman et al. also confirm that the hypodermis (the bottom layer) is important for pigment production, being enriched with different types of pigment cells such as xanthophores, melanophores and iridophores.