This species was first described by Alfred Philpott in 1926 and named Selidosema fluminea. Philpott and Stewart Lindsay discovered this species at Flora River on the track to Mount Arthur tableland at an altitude of approximately 1000m. In 1928, in his book The Butterflies and Moths of New Zealand, George Hudson discussed the species as a synonym of Selidosema productata. Later in 1928 Philpott stated that the moth he described in 1926 was a separate species explaining that although both productata and fluminea were variable, fluminea could be distinguished from the former species by its shorter antennal pectinations and the difference in the male genitalia. Hudson accepted this and discussed and illustrated the species under the name S. fluminea in his 1939 publication A supplement to the butterflies and moths of New Zealand. In 1988 John S. Dugdale assigned the species to the genus Pseudocoremia. The hototype specimen is held at the New Zealand Arthropod Collection.