Tapellaria isidiata is a species of corticolous lichen in the family Lecanoraceae.

Found in Cameroon, it was described as a new species in 2021 by lichenologists Klaus Kalb and André Aptroot.

The type was collected from Campo (South Province), where it was found growing on tree bark on a beach.

The lichen has a glossy, mineral-grey thallus with whitish patches, and is bordered by a black hypothallus measuring 0.2–0.6 mm wide.

The specific epithet isidiata refers to the presence of isidia, a characteristic of this species: it is the first in genus Tapellaria to have vegetative propagules.