ID sea hare with shell?

[Peter Houde]

Please help ID with hitchhiker that came in on red "fireball" macroalgae from Florida and showed up in QT after about a week. At first glance I thought it was a Stomatella snail because it is mostly bare and slug-like, but it definitely has a small thin shell that sits up like a bump towards its tail end. It isn't a snail at all because it lacks tentacles (stalked eyes) and has no ventrally directed mouth. It has a delineated "head shield" that is markedly separate anteriorly from a lower extension of what I interpret as part of the foot. Together, the two look like lips that are fairly constantly "gulping". The mouth appears to be between the lips, facing anteriorly. There are two well developed black eye spots surrounded by an unpigmented region. The entire rest of the body is covered with pigment spots. Overall, it is about 12 mm (1/2 inch) long, 3-4 mm wide, equally tall anteriorly, taller at the shell posteriorly, and with a flat beaver-like tail end. It's not a flatworm because apart from the vey tail end it is not flat. Kind of cute and creepy all at the same time.

 

[Peter Houde]

Nevermind, I found it: Haminoea sp. Perhaps not from Florida at all because it more closely resembles some West coast (of North America) species like H. vesicula than it does H. antillarum. My guy might be a youngster. Some species that have been studied have narrow diets of cyanobacteria, diatoms, algal detritus, and foraminifera, but the following table was published by Malaquias et al. For the most part, this guy appears to be reef safe. I might keep him ... maybe in QT.

Malaquias, Manuel & Condinho , Silvia & Cervera, Juan Lucas & Sprung , Martin . (2004). Diet and feeding biology of Haminoea orbygniana (Mollusca: Gastropoda: Cephalaspidea). Journal of the Marine Biological Association of the UK. 84. 767 - 772