Well my guess is this...
As many of you know, the word Tarutaru closely resembles the word Tarter Sauce™ in Japanese. Now if you will take note of the opening trailer, it shows a Galka fighting a bunch of fish creatures. So lets do the math.
I'm wanting the say that tarutaru are now extinct, because the fish ate them, and that's why the Galka is so upset and killing all the fish. It's obvious that this is a hidden teaser about FFXIV. The only way Tarutaru will exist in the game, is as Ghost type mobs, and only in Sea type Dungeons. I mean, it's obvious isn't it?
Long Live Vana Diel.