What is this.

[vetteguy53081]

This is a polynoidae which include many species of short and flat marine worms found all over the world.
They’re characterised by scales that cover their bodies called elytra, and while little is known about their eating habits, researchers have suggested that they’re active hunters, which is good news for pretty much no one. And here’s the best bit.. . . . The part that looks like a head with no eyes is actually a retractable proboscis which is a tubular sucking mouthpart that the scale worm usually turns inside-out and folds up into its body.
Like an actual Xenomorph, when it’s ready to feed, it unfurls this appendage and tears apart its prey with its sharp mouthparts.
These tiny carnivores feed on small prey such as crustaceans, echinderms, other polychaetes, and snails. They also feed on sponges. Yours is a , Lepidonotus melanogrammus. This scale worm is very often seen crawling over the Banded Brittle Star (Ophionereis schayeri), but the nature of the association between the two species is unknown. Both the brittle star and the scale worm can also often be found by themselves.

 

[Kanshi]

So, I found this, but the distribution says southern Australia. My rock came from Florida gulf.

 

[ssunthar]

there is something to the weight of 900 different species, I'd assume it is possible a couple species could hunt a starfish, but I have not read about it yet, some eat sponges, some hunt various pods, some scavenge. why do you ask?

Just wanted to know if we need to be careful about scale worms.

 

[king aiptasia]

So, I found this, but the distribution says southern Australia. My rock came from Florida gulf.

you are correct, the mentioned one is an australian species. I personally would not pin any identification on your animal yet, I simply don't have experience identifying them further. ust know that if it has been there so long without issue, whatever it is eating is likely inconspicuous itself.

Just wanted to know if we need to be careful about scale worms.

i would not be concerned, I have not heard of them being common active hitchhikers, pests or risks, despite being abundant animals with huge distributions, and for some species reported predatory habits

 

[king aiptasia]

Just wanted to know if we need to be careful about scale worms.

one report i was reading yesterday mentioned amphipods, sponge spicules, assorted small animal parts in the stomachs of dissected worms. I'd assume actually some aquarists wouldn't mind a guest that munches assorted microfauna, keeping populations in check

 

[ssunthar]

Hermodice carunculata is one of the most commonly encountered worm that is not starfish safe, but this is an amphinomidae

Thanks for the clarification.. so it is the bearded fire worm that we need to be careful with. Researched a little and looks like some scale worms have symbiotic relationship with starfish... thanks.

 

[ssunthar]

This is a polynoidae which include many species of short and flat marine worms found all over the world.
They’re characterised by scales that cover their bodies called elytra, and while little is known about their eating habits, researchers have suggested that they’re active hunters, which is good news for pretty much no one. And here’s the best bit.. . . . The part that looks like a head with no eyes is actually a retractable proboscis which is a tubular sucking mouthpart that the scale worm usually turns inside-out and folds up into its body.
Like an actual Xenomorph, when it’s ready to feed, it unfurls this appendage and tears apart its prey with its sharp mouthparts.
These tiny carnivores feed on small prey such as crustaceans, echinderms, other polychaetes, and snails. They also feed on sponges. Yours is a , Lepidonotus melanogrammus. This scale worm is very often seen crawling over the Banded Brittle Star (Ophionereis schayeri), but the nature of the association between the two species is unknown. Both the brittle star and the scale worm can also often be found by themselves.

Very interesting, thanks.

 

[king aiptasia]

Thanks for the clarification.. so it is the bearded fire worm that we need to be careful with. Researched a little and looks like some scale worms have symbiotic relationship with starfish... thanks.

yeah they got a reputation as coral killers but in nature they really are more predictable at eating some sea urchins and some starfish, some even mention them as a natural biological control for some echinoderms perhaps even the crown of thorns starfish

 

[vetteguy53081]

So, I found this, but the distribution says southern Australia. My rock came from Florida gulf.

Common in australia but confined to these waters. Its possible also that it was pre-existing and exploring your caribbean rock.