The division of the Mygalomorphae into two clades, Atypoidea and Avicularioidea, has been established in many studies.
[1] The name is based on the family name "Aviculariidae", a junior synonym of Theraphosidae,[6] ultimately deriving from the genus Avicularia.
The Atypoidea retain some vestiges of abdominal segmentation in the form of dorsal tergites; the Avicularioidea lack these.
Relationships within the Avicularioidea are not settled as of September 2018[update].
[2] The families included in the Avicularoidea as of January 2024[update] are:[2][3][4] Also included is the extinct family Fossilcalcaridae (Cretaceous)[8] and the incertae sedis genera Cretamygale (Cretaceous) and Rosamygale (Triassic).