Malmidea atlanticoides is a little-known species of corticolous (bark-dwelling), crustose lichen in the family Malmideaceae.

The type specimen was collected by the authors from the Parque Nacional Serra de Itabaiana [pt] (Sergipe) at an elevation of 190 m (620 ft).

The medulla of the verrucae and the thallus is orange-yellow, showing spot test reactions of K+ (orange to reddish) and P+ (vermilion).

The apothecial discs are flat to slightly concave, and their colour varies from beige to light brownish.

[1] Chemically, the species is characterised by the presence of atranorin as a major component, along with an unknown anthraquinone substance, detectable using thin-layer chromatography.