Bathelium inspersomastoideum is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. Found in Bolivia, it was formally described as a new species in 2016 by lichenologists Adam Flakus and André Aptroot. The type specimen was collected from Plan de Manejo AISU in the Rios Blanco y Negro Wildlife Reserve (Guarayos Province, Santa Cruz Department) at an altitude of 242m (794feet); there, it was found growing on bark in a lowland Amazon forest. It is only known to occur in this and similar habitats in Bolivia. The species epithet refers to both its (i.e., interpenetrated with granules) and its resemblance to B. mastoideum.