Crustospathula was
circumscribed by lichenologist
André Aptroot in 1998, with
Crustospathula cartilaginea as the
type species. This species was discovered by Aptroot in
Madang Province,
Papua New Guinea in an undisturbed
tropical lowland
rain forest. It was, according to Aptroot, the known instance of a
crustose lichen with stalked, cartilaginous, labriform
soralia. For this reason, it could not be assigned to any known genera, and
Crustospathula was created to hold it. Aptroot initially assigned the genus tentatively to the family
Bacidiaceae, because of the resemblance of generative structures with certain species of
Bacidia. It was later in the
Ramalinaceae, until
molecular phylogenetic analysis determined that its true placement belonged in the Malmideaceae. ==Description==