Zetesima portentosa is a moth in the family Depressariidae. It was described by August Busck in 1914. It is found in Panama.[1]
The wingspan is about 16 mm. The forewings are dark brown with obscure, blackish brown markings and with light ochreous costal and terminal edges. There is a strong costal fold reaching nearly to the middle of the wing, which contains a cluster of long, broad, iridescent scales and there is a round black dot at the end of the cilia, edged by ochreous scales. A black, ill-defined streak is found on the outer and upper edge of the cell and there is a series of ill-defined, black, marginal spots around the costal, apical, and terminal edges. The hindwings are blackish brown with a light ochreous costal space covered by the forewings.[2]