An ectodermal placode is a thickening of the ectoderm that is the primordium of many structures derived from the ectoderm[GO].

consder adding placodal ectoderm as a distinct class? Also place placodal ectoderm as develops_from ectoderm; need to check taxon-appropriateness

in GO, covers optic, otic, olfactory, mammary, hair, tooth, sebaceous - and also insect structures

uberon

epithelial placode

UBERON:0005085

http://purl.obolibrary.org/obo/uberon.owl, http://purl.obolibrary.org/obo/cl.owl

With the exception of the adenohypophysis, homologues of the nonneurogenic placodes (e.g. placodes giving rise to the teeth, hair follicles and lens), appear to be lacking in invertebrate chordates.