The order Rodentia may be divided into suborders, infraorders, superfamilies and families. The families are classified over suborders and superfamilies as below. Of the presently recognized suborders, several may be paraphyletic, as well. Turtles are divided into two extant suborders&colon; Cryptodira and Pleurodira. Order Thysanoptera includes 5,500 species classified into two suborders distinguished by the ovipositor. Primates are divided into two distinct suborders (see diagram under History of terminology). Thyreophora includes various subgroups, including the suborders Ankylosauria and Stegosauria. The Vombatiformes are one of the three suborders of the large marsupial order Diprotodontia. Psocodea contains around 11,000 species, divided among seven suborders. Phthiraptera, the lice, includes 5,000 described species divided into 4 suborders. These make up one of two major primate suborders, haplorrhini, and this group includes humans. The 10 families belonging to Urodela are divided into three suborders. There are more than 5,500 species in 41 families in three suborders. Arachnologists currently divide spiders into two suborders with about 114 families. The order is divided into eleven suborders.