Olive Sapsucker, Hermaea oliviae
This beautiful little sapsucker is rarely seen and it was certainly a surprise to find this tiny Hermae oliviae feeding on some red filamentous algae in the shallows. This particular animal has a full set of cerata, something that seems to be fairly rare among the specimens I’ve seen documented. They tend to autotomize their cerata at the slightest provocation, so it’s pretty clear that this one was leading a pretty special life. They can vary in colour — anywhere from a dark olive brown to bright pink. I’m not sure how large they can get, but this one was around 15mm. As beautiful as this animal is, it is NOT a nudibranch; it is a sacoglossan — a herbivore. The Sea Slugs of Hawaii site offers up a good description of this order.