New Clam Pics

I have two corceas blue and purple. I also have a tear drop maxi, brown and just got this huge guy. He seems to be in good health. The lfs thought he was a derasa but I'm sure he is a squamosa. Any advice??? Do the other look good and healthy?? HE is under t5ho, and everything in my tank has done well. Growth and color wise.
the first pic is the new one, it looks kinda flat at the bottom because of the angle

 

sorry the last pic is hard too see, but I don't think the others are gapping or anything. They actually seem have gotten bigger.

 

awesome clams....

 

that is definatly a squamosa not a dersa if you look at the shell he will have ridges like scalloping dersas are smooth.niceeeeeeeeeee

 

good lookin clams!

 

so they are not gapping?

 

nice looking tank! how deep is it and what is your lighting set up? I see t5's....how many, size and name of bulbs all the good stuff....

 

Nice clam and great looking tank my friend. Luna

 

Derasa Clam (Tridacna derasa)
Not a Derasa clam as Derasa's have a smooth shell for the most part, plus they have mainly orange, tan, green and brown coloration with lines along the mantles surface. Squamosa clams have scutes or ridges as mentioned above and consist of numerous varying colored patterns that are mainly rounded in style.
The shell of a Derasa clam is more elongated whereas the shell of the Squamosa clam is more rounded. The mantle doesn't extend very far over the top of the shell on Derasa clams either as it does on Squamosa clams!

 

Thanks all, t5 ho 6x54 watt. no individual reflectors. 75 gal.