Suborders are an intermediate classification rank that sit below an order. There can be several closely related suborders in an order which might be further divided into either infraorders or families. All modern snakes are placed within a suborder (Serpentes). Theropoda is another suborder to which several of the famous carnivorous dinosaurs belong.
In biological classification, rank is the level in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, and class. Each rank subsumes under it a number of less general categories. The rank of species, and specification of the genus to which the species belongs is basic, which means that it may not be necessary to specify ranks other than these.