The post-Paleozoic Asterozoa include the Asteroidea and the Ophiuroidea. Various workers believe the arguments in support of a common Paleozoic ancestry for the two are very strong and rank them as subclasses of the class Stelleroidea. Other workers feel asteroids and ophiuroids are worthy of class-level recognition, either stressing their disparate early development or because living representatives are thought to be distinctive at the class level on par with the other living classes.