The suborder Archaeobactrachia is the primitive frog and toad suborder. The suborder contains only four families with under 30 total species in total. These frogs are primitive because they have characteristics common with extinct frogs and toads and that are not present in the other frog families. The common thing that all frogs and toads of Archaeobactrachia have in common is free vertebrae instead of fused vertebrae. Fused vertebrae means that the vertebrae is attached to the ribs while free vertebrae are not fused.