The pharyngeal teeth are the ones you hear when they're chomping on pellets. He'll crunch away on them and sound like a human eating really firm carrots or nuts or something.
Nope, didn't photoshop them in. They're often hidden by the lips. I always thought that the teeth on the jaws were more like bumpy plates until Homer flipped out one day. He was living with a small pair of breeding nics in a 75 gal. They'd give him a hard time if he went into their corner of the tank and the fact that someone was standing up to him had him ticked off. During a water change he bit me and drew blood. Later he was gnashing his teeth at the glass and I was surprised to see those chompers.
Sold the pair of nic's and sent their fry to a few lfs's. Homer lives very peacefully with subordinates, but will not tolerate anyone else establishing territory in his tank. Besides, he's too big now for others to live with him.