The RTA clade is a clade of araneomorph spiders, united by the possession of a retrolateral tibial apophysis – a backward-facing projection on the tibia of the male pedipalp. Most of the members of the clade are wanderers and do not build webs. Despite making up approximately half of all modern spider diversity, there are no unambiguous records of the group from the Mesozoic and molecular clock evidence suggests that the group began to diversify during the Late Cretaceous.
Families In 2005, Coddington included 39 families in a cladogram showing the RTA clade:
Agelenidae Amaurobiidae Ammoxenidae Amphinectidae (paraphyletic; merged into Desidae) Anyphaenidae Cithaeronidae Clubionidae Corinnidae Cryptothelidae Ctenidae Desidae Dictynidae Gallieniellidae Gnaphosidae Lamponidae Liocranidae Lycosidae Miturgidae (paraphyletic) Oxyopidae Philodromidae Phyxelididae Pisauridae Psechridae Salticidae Selenopidae Senoculidae Sparassidae Stiphidiidae Tengellidae (now merged into Zoropsidae) Thomisidae Titanoecidae Trechaleidae Trochanteriidae Zodariidae Zoridae (now a synonym of Miturgidae) Zorocratidae (no longer accepted; most genera now placed in Udubidae) Zoropsidae
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