The polyclad flatworm, Thysanozoon nigropapillosum is a tropical flatworm species that belongs to the Pseudocerotidae family. This species can be found in the warm waters of Indo – Western Pacific region and has been recorded from South Africa, the Rea Sea, Indonesia, Malayasia, Papua New Guinea and the Great Barrier Reef in Australia. This species can be recognised by its black velvet body that is covered in small yellow tipped papillae and it has a white margin around the edge. This species is generally found on coral reefs from depths of 1 metre to 30 metres.
Thysanozoon nigropapillosum is known to grow to at least 8cm in length.