Pseudimatidium gomescostai is a species of beetle of the family Chrysomelidae. It is found in Argentina (Misiones) and Brazil (Rio Grande do Sul).
The recorded host plants for this species are Arecastrum romanzoffianum, Cocos eriospatha, Phoenix canariensis, Washingtonia filifera, Phoenix roebelenii, Pritchardia filamentosa, Phoenix humilis, Phoenix roebeleni and Phoenix dactylifera.