Complex sentence: The lower jaws were very deep and helped support massive chewing muscles to help chew coarse fibrous plants; a distinctive bar of bone projects downwards on the cheek, extending over the lower jaw, perhaps providing an anchor for powerful snout muscles.
Split into simpler sentences: The lower jaws were very deep and helped support massive chewing muscles to help chew coarse fibrous plants. A distinctive bar of bone projects downwards on the cheek, extending over the lower jaw, perhaps providing an anchor for powerful snout muscles.