Large Tridacna Clam ID - I'm stumped

Bongo Shrimp

Bongo Shrimp

P. ceratophthalma
I have been trying to ID my new Tridacna and so far I have convinced myself it is at least two different species so I am stumped. I'm usually really good at IDing just about everything, but not clams. Now I know it has no foot but I have hear before that some species don't have a foot. I don't claim to be an expert on clams so if that's not true don't hate me :).

Edit: forgot to add that it's about 8"

Here are the pics:
IMG_8743_zpsf0308437.jpg


IMG_8742_zps87f96e2a.jpg


IMG_8748_zps080eefd6.jpg


IMG_8746_zpsb7ad80df.jpg


IMG_8745_zps5674ecae.jpg
 
Don't take my word on it, but I suspect that might be a Gigas.. which begs the question: Where in the world did you get that clam?

At the same time I also want to say it's a Derasa clam. Usually the "eyes" are outlined in blue (I think) and not completely colored in. The slightly protruding ridges on the shell also lead me to think it may be a Derasa.

As for the foot not being there... typically (If I remember correctly) once the larger species of clams reach a certain size (ie heavy weight) they simply lose their foot as they no longer need it to anchor them.
 
Electrobes said:
Don't take my word on it, but I suspect that might be a Gigas.. which begs the question: Where in the world did you get that clam?

As for the foot not being there... typically (If I remember correctly) once the larger species of clams reach a certain size (ie heavy weight) they simply lose their foot as they no longer need it to anchor them.
Click to expand...

I also came to the conclusion that it might be a gigas until I read that gigas don't have the fringy tentacles around the intake valve.

I also should not that the left area on the bottom of the clam is hard and not soft even though it looks like it might be soft.
 
I have heard of hybrids between Gigas and Derasas being found in the trade, but its quite rare. Maybe thats what he is?
 
Haleyf1024 said:
I have heard of hybrids between Gigas and Derasas being found in the trade, but its quite rare. Maybe thats what he is?
Click to expand...

Haleyf1024 said:
http://animal-world.com/Aquarium-Coral-Reefs/Gigas-Clam-Giant-Clam

This site briefly mentions it and says hybrids may have those tenticals like Derasas. It also says that Gigas clams can have the frills at young ages. Where did you get this clam?! Lol
Click to expand...

Hmm that's very interesting. Interesting, but making my head spin. Maybe this is indeed a hybrid?
 
Wild looking clam. Has the Gigas blue spots, the Deresa green fringing, and Squamosa coloration. Nice score! My guess is either a funky Deresa or a Deresa/Gigas hybrid.
 
it's a derasa. There are at least two 'types' of dersasas available in the inudustry; these (with the holes in the mantle, and the more traditional 'palau' derasasa with essentially come in two flavors (striped and blotched). The ones with the holes, as yours, tend to be more consistent in overall pattern...both 'kinds' of derasas have been available for many many years (20+) at least. Sometimes one kind dominates the market. Right now, seems to be more just the old school MMDC Palau kind (as offered at DFS)
 
wjgeese said:
it's a derasa. There are at least two 'types' of dersasas available in the inudustry; these (with the holes in the mantle, and the more traditional 'palau' derasasa with essentially come in two flavors (striped and blotched). The ones with the holes, as yours, tend to be more consistent in overall pattern...both 'kinds' of derasas have been available for many many years (20+) at least. Sometimes one kind dominates the market. Right now, seems to be more just the old school MMDC Palau kind (as offered at DFS)
Click to expand...

Do you have any links to identification of this type of derasa? I so far have found pictures of similar morphs on the forums, but have not found any non-forum post showing the difference. Even Giant Clams in the Sea and the Aquarium by James Fatheree is of no help. Also, the way I see it, is there is no real way to know if it is hybridization without some sort of DNA testing and comparison with known derasa and known gigas. Until I see evidence supporting the argument that it is not a hybrid, I can't discount that possibility. I have read multiple scientific articles which suggest that hybridization may be possible, but none which definitively say it happens. Also, there are quite a few articles (non-scientific) which explain that it probably happens.
s
Right now the clam is coloring up nicely and is indeed showing the classic short lines that other derasas have. So far I'm not convinced wither way. All I DO know is that others have had the same morph.
 
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