Loricariidae is the largest family of catfish (order Siluriformes), with 92 genera and just over 680 species. Loricariids originate from freshwater habitats of Costa Rica, Panama, and tropical and subtropical South America. These fish are noted for the bony plates covering their bodies and their suckermouths. Several genera are sold as "plecos", notably the suckermouth catfish, Hypostomus plecostomus, and are popular as aquarium fish. Common names Members of the family Loricariidae are commonly referred to as loricariids, suckermouth armoured catfishes, or armoured catfish. The name "plecostomus", and its shortened forms "pleco" and "plec", are used for many Loricariidae, since Plecostomus plecostomus (now called Hypostomus plecostomus) was one of the first loricariid species imported for the fish-keeping hobby. Some loricariids are not normally considered "plecostomus", such as Farlowella catfish. In their native range, these fish are known as cascudos or acarís. L-numbers Some types of loricariids are often referred to by their 'L-number'; this has become common since imports of loricariid catfish from South America often included specimens that had not been taxonomically described. Currently, L-numbers are used not only by fish-keeping enthusiasts, but also by biologists, since they represent a useful stopgap until a new species of fish is given a full taxonomic name. In some cases, two different L-numbered catfish have turned out to be different populations of the same species, while in other cases, multiple (but superficially similar) species have all been traded under a single L-number. Taxonomy and evolution Because of their highly specialized morphology, loricariids have been recognized as a monophyletic assemblage in even the earliest classifications of the Siluriformes, meaning they consist of a natural grouping with a common ancestor and all of its descendants. Loricariidae is one of seven families in the superfamily Loricarioidea, along with Amphiliidae, Trichomycteridae, Nematogenyidae, Callichthyidae, Scoloplacidae, and Astroblepidae. Some of these families also exhibit suckermouths or armor, although never in the same individual, as in loricariids. This is the largest catfish family, including about 684 species in around 92 genera, with new species being described each year. However, this family is in flux, and revisions are likely. For example, the subfamily Ancistrinae is accepted as late as the 2006 edition of Nelson's Fishes of the World; it later becomes grouped as a tribe, because of its recognition as a sister group to the Pterygoplichthyini. Under Ambruster, six subfamilies are recognized: Delturinae, Hypoptopomatinae, Hypostominae, Lithogeneinae, Loricariinae, and Neoplecostominae. Monophyly for