Well. This started out as a sketch I swear. Also, I'm sure you will notice this is not a marine organism. I guess I have a hard time sticking to my word when it comes to what I will draw in what order haha. Also, I know at this angle it's a little hard to tell what the rest of the body looks like, but I will have a more referencey drawing up in the next little bit.
The Jaku's jaws evolved in a peculiar manner, unlike many Skathan creatures it not only has the split set of "jaws" but it also has a lower jaw. It's upper jaw however has become very reduced to accomodate the large set of split mandibles that take up a good portion of the head. The Jaku is bipedal, running on it's "front legs", which have evolved to become it's only legs. The mid set of legs has reduced to nothing more than colorful spurs on the sides of the body (not shown in picture). The back legs followed a similar route, though more of them is left over, two larger spurs are folded against the tail.
The Jaku is a fierce predator that lives in the shadow of the canopy of Tolaa stalks (more information on these later), it's general body color is dark, allowing it to blend in easily with the dark stalks of the Tolaa and other organisms. The biolights along it's sides and jaws are used in camouflage as well as in mating displays.