Most spider species are Araneomorphae, which have fangs that face towards each other, increasing the orientations that they can employ during prey-capture.

They have fewer book lungs (when present) – usually one pair – and the females typically live one year.

The Mygalomorphae have fangs that face towards the ground, and which are parallel to the long axis of the spider's body, thus they have only one orientation they can employ during prey capture.

In older schemes, the Araneomorphae were divided into two lineages, the Hypochilae (containing only the family Hypochilidae), and the Neocribellatae.

[4] Hypochilidae Filistatidae Synspermiata Leptonetidae Austrochiloidea Palpimanoidea Entelegynae The blue bar to the right shows the former Haplogynae in the sense of Coddington (2005).