Can You Identify This Hybrid?

Sicklid

New member
Can you ID this Hybrid? . The mantle is conspicuously like a T. squamosa... but the shell does not have the characteristic worn scutes of a T. squamosa, and instead looks worn and ribbed like a T. derasa. Someone had written in to Bob Fenner asking, and I was wondering also.

Clam.JPG
 

K. Lee

Reefer
The shell looks like a T. gigas to me.

I think just like with corals color is a secondary characteristtic and a pretty weak tool for species identifivation in clams.

I thought "Teardrops" were only T. maxima, but, I was wrong. ;)
 

Peabody

Premium Member
Hmmm....it's not a Gigas "proper" because they don't extend their mantles beyond the shell.

I wouldn't have guess it is a hybrid. I would have thought a rather unique maxima or squamosa. Are you sure it's a hybrid?
 

K. Lee

Reefer
Peabody said:
Hmmm....it's not a Gigas "proper" because they don't extend their mantles beyond the shell.

I wouldn't have guess it is a hybrid. I would have thought a rather unique maxima or squamosa. Are you sure it's a hybrid?

T. gigas sure do. Hippopus sp. don't.

But on closer looking, it appears there are tentacles on the outer incurrent siphon which are absent on T. gigas. That could be a function of the coloration on the mantle however. A close look at or into the incurrent siphon would help, a lot. :D
 

Peabody

Premium Member
Really? On the gigas I've seen (which admittidly isn't many!) the mantle barely extended beyong the shell. Is this not usually the case?
 

Sicklid

New member
I called it a hybrid because Anthony at Wet Web Media called it a hybrid. Here is the original Q&A:



"Can you please identify this type of clam for me. It has a brownish look to it although it looks a little different in the picture. Thank You."

"I would need a better picture to be sure but you may have a very interesting clam here! Tridacnids are rather easy to identify but yours looks like it could be a hybrid of two species known to hybridize. The mantle is conspicuously like a T. squamosa... but the shell does not have the characteristic worn scutes of a T. squamosa, and instead looks worn and ribbed like a T. derasa. Still the picture is not clear enough. A close up of the shell and mantle separately would help if clear. Best regards, Anthony"
 

AQUAN8TOR

New member
That clam looks like a very interesting and unique squamosa to me. Except for the color, and scutes, the pattern is identical to my squamosa. The shell doesn't seem to be creased enough for a maxima. Maybe its a derasa; if it is, it's especially colorful and patterned. Most derasas I've seen aren't nearly as 'marbled'---unlike a teardrop clam, which looks nothing like this clam. Also, I've never seen gigas clams with their mantles much beyond the shell, either; even in Knop's book, there are very few pictures of gigas clams with their mantles past the edge of the shells.
 

K. Lee

Reefer
The clams pictured may have been startled. It is their nature to withdraw. Either shadows, or a camera flash would trigger a healthy giant clam to withdraw, or could.

Here's a pic I just took of my T. gigas.
 
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AQUAN8TOR

New member
nice clam. I definitely know about clam mantle contractions in all species, in response to shadow, movement, etc. I just had never seen one as open as yours apparently is, even in the MANY years I've been a hobbyist. I stand corrected. Thankyou.
 
jazzyreef- check out the "HYPER" mantle extension on my Tridacna {seen through this link on the front page of my website.}
http://home.rochester.rr.com/garysreef/
The mantle is so floppy some folks thought my clam was "gaping"!

sicklid- I think you have a T. squamosa with worn down scutes....
look at the frilly incurrent siphon. I believe T. derasa and T. squamosa have been known to interbreed...it's possible yours' might be a cross of the two.
 
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