Caribbean zoanthid and boring sponge

Another common subject - which hopefully is easy with the right book:

I guess that the zoanthids are: Parazoanthus parasiticus, but how do you tell these from P. catenularis?

And the sponge - I don't know. I don't find boring and encrusting sponges very interesting. But, I'd like to know this ones name.

Hopefully the relationship between the two and the Cayman Islands location should help.

Alex

I cant make a guess as to the sponge or the zoanthid. You need to zoom in on the polys and zoom out on the sponge.

But here's what Paul Humann says about the two types of zoanthids.

P. paracasiticus : Blunt tentacles numbering to 28 are brown, yellow-brown, light greenish-brown or greenish yellow; oral disk somewhat darker. Body white to grayish-white........P. catenularis, are distinguished [ from P. paracasiticus ] by 20 brown to yellow-brown, pointed tentacles; oral disk brown, darker toward center; body whiteish, usually deeper than 60 ft (P. paracasiticus is listed depth range 25-100ft).

Understood.

Here is a crop of the zoanthid:

I get between 22 and 24 tentacles on most of them. And given the fact it was shallow I'll go with P. paracasiticus.

And here is the sponge:

Alex