"Becoming vegetarian? Isn't this called an omnivore?"
Not exactly --- but I had the same thought and looked up the definition.
"Omnivores" --- the most common example people humans and bears BTW --- have a pretty unique set of both meat-eating (front, tearing) teeth and plant eating (back, flat grinders).
This guy, in contrast, had flat teeth all around --- but possessed the BODY of a preditor --- legs, eyes-in-front (compare and contrast wolf vs. deer).
There are lean, mean, pointy-tooth machines just like this guy (sharing other family traits) earlier.
And fat wide-eyed flat-toothed guys (but still with same family traits) after.
Hence, "transitional" vs. settled omnivore.
Not the whole puzzle, but certainly "some evidence."
There goes my attempt at being funny... I'll leave that to DFU from now on...