Not to be rude, but what is this speculation based on again?
If it's that convenient "what was the name of the production during filming?" question that's fueling your speculation, then you're following a theory that was created and based on zero fact colletion efforts and zero evidence collection. The only thing that remotely hints that there could be a sea creature MUTO based on a Nautilus is that one of the MUTO's is multi-limbed, but that's not nearly enough evidence to support such a theory when so many other creatures and possibilities fall into that category.
There are four important facts that point to the MUTOs being land/air based creatures and not aquatic.
One, the numerous pictures of the sink holes. Two, none of the information leaks or shots in the trailer point to uniquely aquatic locations or settings. Three, the fact that both of the teasers were showing land based enemies. And four, the official information given thus far in the toys confirms a MUTO with wings.
The teasers weren't final in any way, that's true, but the fact that no aquatic creatures were shown or even hinted of in either one of them, let alone the official trailer, doesn't bode well for an aquatic MUTO. Sure the argument could be made that "they're trying to surprise us," but that's an incredibly flimsy argument and it has no evidence to support it that actually has merit.
Just sayin'.
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