Squamosa dying.

[Minh Nguyen]

You'll never see a maxima clam with the deep indentations of the shell or the large scutes that are displayed on this clam. It's distinctively squamosa. Most maxima clams are generally "straight" along the length of the shell or bulge in the middle. The shape and pattern of the mantle is also indicative of squamosa, but that's a secondary indication......

Greg

Greg,
Maxima and Squamosa have the most indentations of their shells and largest scutes. Tony’s picture show nothing that one can use to differentiate the two using the shell. It is not very prominent at all IMO. The mantle coloration is too destroyed to give clear differentiation between Maxima and Squamosa. It certainly can be c/w a gold Maxima. The spots on the edge of the mantels, however, make it more likely to be Maxima.
All in all, IMO, the picture indicated that it is more likely Maxima. If Tony can give a picture of the byssus opening (bottom of the shell). This will settle it (100%).
I really don't see how one can be 100% sure that the clam pictured by Tony is a Squamosa. IMO, it is much more likely to be a Maxima.

Both of the pictures you show, the first is clearly a Squamosa. The second picture is by not a picture one can use to positively ID the clam as a Squamosa. It has very many characteristic of a larger Derasa. In fact, without knowing anything else, I would have to say that the picture shows the clam to be a Derasa instead of a Squamosa. I got one just like it.

The coloration is typical of a Derasa, the lack of extensive indentaiton of the mantle and the narrowness of the valley between the mantles indicated that this is a Derasa.
Greg, are both of the clams picture are yours clams?

And maxima clams. The shells are generally straight and the mantles are a little "pinched" along the shell. It's easy to confuse crocea and maxima clams, but squamosa clams are distinctive.

Most of the clams are all pretty distinctive. However, without considering the coloration but only use the shape of the mantle, it is easy to tell a Crocea from Maxima and Squamosa because Crocea do not have the strong indentation or "pinched" as Squamosa and Maxima.
Minh

 

[GSchiemer]

The distance between the scutes are typical of squamosa. The scutes on maxima clams are much closer together. Also, squamosa clams can have "eyes" along the mantle. Take a look on page 24 in Knop's book for an example. I'm confident it's a squamosa clam. Willing to make a friendly wager?

You're correct on the second "squamosa" pic that I posted. It is a derasa. I attached the wrong picture. Here's the one I meant to attach. You can see the large scutes and the wide spacing, which is indicative of squamosa. This is my squamosa clam back in 1996. It's considerably larger now and in a position that makes it difficult to take a good picture.
The other pics are NOT my clams.

Greg

 

[Minh Nguyen]

Greg,
I love to wager with you. :lol:
Let wager a few frags, or a clam shall we

Tony,
If you can please post a picture of the byssus opening of your clam after it died. This would settle the wager between Greg and I.
I am very sorry about your clam, and sorry that we hijacked your thread.

The distance between the scutes are typical of squamosa. The scutes on maxima clams are much closer together

All depends on the individual clam growth rate. I certainly have Maxima with similar looking scutes.

Take a look on page 24 in Knop's book for an example

I saw that pictures also. However, I have my doubt that the pictured clam is an Squamosa. It would not be the only error in this otherwise great book. If you can find another picture of an Squamosa with similar eyespots, or if you can find a Maxima that lack these eyespots, then you got a case. Otherwise you, like I am, must consider the picture mentioned is in error.
Please keep in mind that I am not saying that only Maxima have these eyespots or Squamosa do not have these eyespots. However, Maxima have most prominent spots, then Crocea, then Derasa. Squamosa rarely have these spots and when they do, they never have them as prominent as the one in Tony's picture.
BTW, you do have a very beautiful Squamosa.

Minh

 

[jamesw]

This one's a tough call since the clam's mantle is in "sub-optimal" condition to say the least.

It could go either way.

Cheers
James

 

[Anonymous]

IIRC, he posted another picture of the same clam when it looked a bit better from the side. I'll try and find the thread. That pic looked like a maxima to me as well, but I'm certainly no expert.

 

[Anonymous]

http://reefs.org/phpBB2/viewtopic.php?t ... lacophoran

There's another pic of the clam in question here, taken from the side with a much better view of the shell.

 

[jamesw]

Thanks Matt.

In that shot, it looks like a Maxima to me. They do have scutes, but they are smaller and closer together than Squamosas.

Cheers
James

 

[Minh Nguyen]

It looks like an Maxima to me too. One way to tell for sure is the byssus opening.
Minh

 

[GSchiemer]

The second picture clinches it. The general shape of the shell (more triangular than oblong); the spacing of the scutes; and the size of the scutes are all indicative of T. squamosa. Still want to place a bet Minh?

Greg

 

[npaden]

I think it is a hybrid.

It definitely has characteristics of both maximas and squamosas IMO. The mantle shape and color lean toward a maxima, the scutes are large and there is decent spacing between them which would lean toward a squamosa, but I have had a maxima that had a very similar shell.

I think you can't tell from those 2 pics.

The clam looks pretty much gone in the first pic in this thread though.

FWIW, Nathan

 

[Minh Nguyen]

The second picture clinches it. The general shape of the shell (more triangular than oblong); the spacing of the scutes; and the size of the scutes are all indicative of T. squamosa. Still want to place a bet Minh?

Greg

You are on Greg.
Minh

 

[jamesw]

How can you guys bet if you both think it's a Squamosa???

Cheers
James

 

[Minh Nguyen]

James,
I think it is a Maxima.
Minh

 

[reefNewbie]

I am truly upset, I have suffered the loss of a clam and you guys are making bets.

lol...just kidding, let me get a picture of the bottom of the shell for you guys when i get home tonite. Can I place bets on this to? :lol:

 

[npaden]

I have seen one clam in the shape yours was in pull through though. Don't pull it out until it starts to stink. :?

 

[reefNewbie]

ok here it is.

 

[Minh Nguyen]

The second picture clinches it. The general shape of the shell (more triangular than oblong); the spacing of the scutes; and the size of the scutes are all indicative of T. squamosa. Still want to place a bet Minh?

Greg

You are on Greg.
Minh

:lol: :lol: Gotcha Greg!!! Payup!!! :lol: :lol:
Thanks Tony
Minh

 

[GSchiemer]

Actually, now it looks like a crocea clam!

The shape and size of the byssal opening changes as Tridacnid clams mature, so I can't conclude anything based on the picture. I don't have any reference that shows these changes by species. Do you know of one?

 

[Minh Nguyen]

Actually, now it looks like a crocea clam!

The shape and size of the byssal opening changes as Tridacnid clams mature, so I can't conclude anything based on the picture. I don't have any reference that shows these changes by species. Do you know of one?

Greg,
That byssus opening is too small for a Crocea, and certainly too big for a Squamosa. It looks just right for a Maxima. The porportion of the opening is about the same with each species even as they growth. Because the shell is open, it does looks a little larger than it actually is. I can't believe you wrote ....I can't conclude anything based on the picture...
We are all wrong sometime. Even I am wrong about clams some time :lol: . The thing to do is to admit it.
Minh

 

[GSchiemer]

Minh,

I'll admit when I'm wrong and I'm always glad to learn something new, but the picture is inconclusive. The byssal opening on squamosa, gigas and derasa clams gets smaller and smaller as the clams mature, to the point where it disappears. I don't see any reason why this couldn't be a small squamosa clam. For that matter, it could just as well be a large crocea clam. I recall a reference that shows the changes in shell shape and byssal opening over time. I'll have to see if I can locate it.

Greg