Irregular echinoids with:
Lower Jurassic (Toarcian) to Recent.
Distinguished from Holectypoida by the lack of buccal notches and the presence of petals. The other major group of irregular echinoids, the Atelostomata, primitively have an elongate apical disc. Only Spatangoida have a compact apical disc like the Neognathostomata, but they have interambulacrum 5 differentiated as a plastron.