What is this?

[UmpaLumpa]

I've been cooking some rock and have noticed a few of these attached. This one fell off. What is it?


http://i109.photobucket.com/albums/n73/umpalumpa_04/whatisthis.jpg

http://i109.photobucket.com/albums/n73/umpalumpa_04/whatisthis2.jpg

http://i109.photobucket.com/albums/n73/umpalumpa_04/whatisthis3.jpg

[UmpaLumpa]

I should mention that this appears to be some kind of filter feeder.

The top part opens up as shown in the picture below.

ETA: ugh I ment to enlarge that part, oh well you get the idea.

http://i109.photobucket.com/albums/n73/umpalumpa_04/opens.jpg

[chrismunn]

is it a mollusk?

[scrmbld33]

tagging along, had something similar a while back, but nobody knew what he was.

heres mine


http://i27.photobucket.com/albums/c187/scrmbld33/fish002a.jpg

[Rendos]

Barnacle?

[UmpaLumpa]

i don't think its a barnacle after googling a few pages of pictures of barnacles

[pagojoe]

It's an Ark Clam (family Arcidae) but I can't tell which species for absolutely certain. The best view for a species-level ID is horizontal so you can see the length-to-width ratio and the overall outline of one of the valves (shells). My best guess is that it's a baby Turkey Wing, Arca zebra:

http://www.jaxshells.org/turkey.htm

Scrmbld33's also looks to be a clam, but I don't think it's in the same family, since it appears to have flutes on the shell. Do you have other pics of it? It might be a venerid clam in the same family as this one (with rather exaggerated flutes):

http://www.george-shells.com/upd4/callanaitis_disjecta_39.jpg

and (disregard the non-shell pics):

http://images.google.com/images?um=1&hl=en&q=bassina&btnG=Search+Images

If you have side-view pics, I can probably narrow down the ID.

Cheers,



Don

[pagojoe]

Here are a couple more species for Umpa to consider, both Indo-Pacific rather than Florida/Caribbean:

http://www.conchology.be/en/availableshells/searchresultsgallery.php?family=ARCIDAE&species=Arca navicularis#f

http://www.conchology.be/en/availableshells/searchresultsgallery.php?family=ARCIDAE&species=Arca ventricosa#f

The crosshatched sculpture looks more like Arca ventricosa, but the shape is closer to Arca zebra or Arca navicularis. It could also be a different species that I haven't come across in my cursory internet search (maybe more likely). I'll let you know if I find a better match.

Cheers,




Don

[UmpaLumpa]

<a href=showthread.php?s=&postid=13767581#post13767581 target=_blank>Originally posted</a> by pagojoe
It's an Ark Clam (family Arcidae) but I can't tell which species for absolutely certain. The best view for a species-level ID is horizontal so you can see the length-to-width ratio and the overall outline of one of the valves (shells). My best guess is that it's a baby Turkey Wing, Arca zebra:

http://www.jaxshells.org/turkey.htm

Scrmbld33's also looks to be a clam, but I don't think it's in the same family, since it appears to have flutes on the shell. Do you have other pics of it? It might be a venerid clam in the same family as this one (with rather exaggerated flutes):

http://www.george-shells.com/upd4/callanaitis_disjecta_39.jpg

and (disregard the non-shell pics):

http://images.google.com/images?um=1&hl=en&q=bassina&btnG=Search+Images

If you have side-view pics, I can probably narrow down the ID.

Cheers,



Don

I can take as many pics as you need. I will take a large side view when I get off work.

[pagojoe]

Hey Umpa,

I can see yours well enough that I would probably recognize the animal if I found it, assuming it's not one of the species I already mentioned. Scrmbld's clam is a different matter, since I can only see it from the edge. I'll actually check some books this evening and see if I can come up with a better ID on yours.

Cheers,




Don

[UmpaLumpa]

<a href=showthread.php?s=&postid=13771025#post13771025 target=_blank>Originally posted</a> by pagojoe
Hey Umpa,

I can see yours well enough that I would probably recognize the animal if I found it, assuming it's not one of the species I already mentioned. Scrmbld's clam is a different matter, since I can only see it from the edge. I'll actually check some books this evening and see if I can come up with a better ID on yours.

Cheers,




Don

Your the closest one so far but this "clam" is triangular. its like a boat almost. It has a "hull" and a "deck" Its all hard shell too. The "deck" opens up on on the "bow" side like with the "stern" side acting like the hinge. It opens up like a beak on a bird but the top beak would be flat like a "deck" would be on a boat, whereas the hull would be the lower part of the beak.

[UmpaLumpa]

Ok here are the requested side pictures. I also have one in my tank of the side of a rock that happened to be open when I was taking the side pics. Yes I know I have an algae problem, thus the reason I am cooking my rock.


http://i109.photobucket.com/albums/n73/umpalumpa_04/detail.jpg

http://i109.photobucket.com/albums/n73/umpalumpa_04/detail2.jpg

http://i109.photobucket.com/albums/n73/umpalumpa_04/detail3.jpg

BTW does anyone know what kind of worm that is off to the left of the "clam"

[justinl]

Arcidae clams are triangular. your worm is a sipunculid; a peanut worm. harmless detritivore.

[pagojoe]

Yes, it's an Ark Clam for sure. The closest one I've found is Guido Poppe's "Arca species" (meaning he's not sure of the ID, although it may be a variation of Arca avellana):

http://www.conchology.be/en/availableshells/shellsforsaledetails.php?uniquenumber=418333#f

More pics, Arca avellana with and without periostracum:

http://www.conchology.be/en/availableshells/shellsforsaledetails.php?uniquenumber=143452#f

http://www.conchology.be/en/availableshells/shellsforsaledetails.php?uniquenumber=148352#f

Cheers,



Don