Plocamopherus margaretae has a pink or red background color heavily speckled all over the body with large white spots and black, almost oval spots. The white spots are of various sizes and are regularly scattered on the notum.

This rare dorid is characterised by the reddish pink background, with large and sparse black spots, and 3 pairs of lateral appendages of which only the last pair seems to possess light-emitting ‘globes'. Furthermore, the anterior body is significantly more dorso-ventrally flattened (like a Chromodoris) than any other member of Plocamopherus and the papillae around the anterior margin of the head are relatively very small. It was previously only known from two specimens – from Myanmar and the United Arab Emirates, so these specimens from Indonesia represents a significant new range extension into the tropical western Pacific Ocean.