Trichoplax was discovered in 1883 by the German zoologist Franz Eilhard Schulze, in a seawater aquarium at the Zoological Institute in Graz, Austria.
Although from the very beginning most researchers who studied Trichoplax in any detail realized that it had no close relationship to other animal phyla, the zoologist Thilo Krumbach published a hypothesis that Trichoplax is a form of the planula larva of the anemone-like hydrozoan Eleutheria krohni in 1907.