The genusAcanthozoon is physically characterized by a dorsal side with small raised papillae and ruffled edges.
Their body is elongate oval. The species of this genus have a complex and very folded pharynx. They also have small pseudo-tentacles that prick up like ears.
Because of their papillated upper surface, they are easily confused with species from the genusThysanozoon, which are also endowed with dorsal papillae. However Acanthozoon possess only a single male copulative organ contrary to Thysanozoon.[2]
Collingwood, 1876, On thirty-one species of marine Planarians, collected partly by the late Dr Kelaart F.L.S. at Trincomalee, and partly by D. Collingwood F.L.S. in the Eastern Seas., Linnean Society of London, Transactions II, Zoology, vol.1, p 83-98.