This large nudibranch species is easily mistaken for a Dendrodoris carbunculosa and I must admit to doing so the first time I found one of these animals. The difference can be subtle, especially if you have no access to the underside of the animal. The D. carbunculosa lacks markings whereas the D. turberculosa has obvious white spots, its notum is more transluscent and its tubercles more ornate. When Cory Pittman caught my mistake in identification he noted that these animals also have diffraction lines present, tubercles that are more complex and marginal folds that extend to the edge. This is why I always direct people to Pittman and Fiene’s Sea Slugs of Hawaii site for further information!
