Infraorders are a subdivision of suborders, an intermediate rank of classification that group together related superfamilies and families. The tarsiers are an infraorder of primates containing a single extant family, whilst shrimps (Caridea) are an infraorder that encompasses many related superfamiles. Ceratopsia is the infraorder that contains all the horned dinosaurs.
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.