From the Greek roots tribo, meaning "grinding" or "pounding", and sphen, meaning "shearing" or "cutting". Tribosphenic molars have both grinding and cutting components. The early marsupials and the placentals have one kind of cheek teeth, the tribosphenic molars. These teeth combine a grinding cusp called the protocone that fits like a pestle on the mortar-like basin known as the talonid heel. These allow animals with them to crush seeds, pulp fruit, and grind leaves, as well as being able to eat insects. These teeth are believed to be a key evolutionary advantage that enabled marsupials and placentals to diversify during the Mesozoic age.