The Araneomorphae, previously called the Labidognatha, are a suborder of spiders. They are distinguished by having chelicerae that point diagonally forward and cross in a pinching action, in contrast to the Mygalomorphae (tarantulas and their close kin), where they point straight down. Most of the spiders that people encounter in daily life belong to this suborder.
Note the difference in the orientations of the chelicerae (fangs) of the two spiders below, representatives of the Orthognatha and the Araneomorphae.
Sphodros rufines
Geolycosa sp.
This Sphodros rufines (left) is making a threat display, and by so doing shows very clearly the orientation of its chelicerae, which go up and down, parallel to the long axis of the spider's body. So it stands as a representative of the suborder Orthognatha.
This Burrowing Wolf Spider (right), Geolycosa sp., is also making a threat display, and with a little care you can see how the fangs slope toward each other. This alignment of the chelicerae is typical of the Araneomorphae. (Click here to see a closeup of the Geolycosa sp. which has been digitally enhanced to make the business end of the chelicerae more easily seen.)
Spiders, suborder Araneomorphae
Platycryptus undatus, a demure but very friendly type of jumping spider.
That is, she is part of a discrete group considered more 'primitive' (closer to the ancestral state) than the araneomorphs, or 'true' spiders.
Araneomorphs are labidognath - the chelicerae face each other and the fangs close in a pinching movement.
Thery're very big, compared to those of most araneomorphs, but her venom glands are small, being contained within the chelicerae (in araneomorphs, they extend back into and occupy a good bit of the body).
Araneomorph spiders: The more advanced spider families, most of which can survive indefinitely in webs or other open environments without suffering desiccation.
The advanced (araneomorph) spider families have one of these on each side of the abdomen close to its front end but primitive spiders (mygalomorphs) have a second pair behind the first.
It is easily seen in fully mature araneomorphs but not in mygalomorphs or immature araneomorphs.