Snail with 3 arms?? What is this??

[burtmacklinfbi]

I picked up a local macro algae here in florida. Wild caught. And one of the hitchhikers looks like a snail. But has 3 appendages that seem to be a defense system. flare orange when disturbed and can also use them to flip itself over. The snail is green. Green shell with blue dots. I’m at a complete loss as to what it could be. Any ideas?

 

[twelvefive]

Maybe a juliidae?

 

[EeyoreIsMySpiritAnimal]

@ISpeakForTheSeas

 

[ISpeakForTheSeas]

Maybe a juliidae?

Pretty close taxonomically (same super family, but a different family); this looks to be a Lobiger sp. that’s missing one of its four “arms” (I’m not at my computer or I might be able to to ID the species).

It’s a Sacoglossan Slug, OP - an algae eater.

The two species I’ve seen diets for (I haven’t looked in depth at these guys yet) suggest that they eat feed on Caulerpa (one specifically C. racemosa). I don’t know if they need their specific algae species to survive, or if it’s just a strong preference like with Elysia spp., which from what I’ve heard will feed on most green algae species in our aquariums.

You’re right about appendages being defense mechanisms - they unfold/unfurl to show off that orange color and make the slug look bigger, and - if they feel threatened enough - the appendages (tentacles) can secrete a sticky substance, detach from the slug (autotomize), and writhe around for while to distract and slow down predators.

Edit: Overall, a super cool find.