Is this just teeth clacking together with little in the middle? Hollow wood, like those percussive frogs you can buy in music stores, might be a starting point, although it might also be too tuned/chromatic/musical. Using actual bone-on-bone impacts that are pitched down might be a useful layer, too. And of course, metallic clacking sounds could be great if you need more weight or high-freq content, if used judiciously in the mix.

Seems like other opportunities for richness, though, could come from a forceful exhalation of breath, tongue/saliva/mouth slaps and other wet sounds, or a grunt/groan that would coincide with a creature's toothy lunge. As you said, meaty hits will do well for filling out the mid-lows. Start hitting those stacks of phonebooks! :-)