 In many groups, a fourth cusp, the hypocone (hypoconid), subsequently evolved (see below).Quadrate (also called quadritubercular or euthemorphic) molars have an additional fourth cusp on the lingual (tongue) side called the hypocone, located posterior to the protocone.Quadrate molars appeared early in mammal evolution and are present in many species, including hedgehogs, raccoons, and many primates, including humans.