Ancistrini is a tribe

Tribe (biology)

In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...

 of catfish

Catfish

Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...

es (order

Order (biology)

In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Siluriformes) of the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Loricariidae

Loricariidae

Loricariidae is the largest family of catfish , with almost 700 species and new species being described each year. Loricariids originate from fresh water habitats of Costa Rica, Panama, and tropical and subtropical South America. These fish are noted for the bony plates covering their bodies and...

.

Taxonomy

Ancistrini has previously been considered a loricariid subfamily. However, it was realized that the subfamily Hypostominae

Hypostominae

Hypostominae is a subfamily of catfishes of the family Loricariidae.Studies conducted with representatives of some genera of Hypostominae showed that within thisgroup, the diploid number ranges from 2n = 52 to 2n = 80...

 would be paraphyletic

Paraphyly

A group of taxa is said to be paraphyletic if the group consists of all the descendants of a hypothetical closest common ancestor minus one or more monophyletic groups of descendants...

 if Ancistrinae continued to be recognized. To continue recognizing the monophyly

Monophyly

In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...

 of this group while returning it to Hypostominae, Hypostominae was broken into several tribes. Pterygoplichthyini

Pterygoplichthyini

Pterygoplichthyini is a tribe of catfishes of the family Loricariidae. It includes two genera, Pterygoplichthys and the currently undescribed genus referred to as the Hemiancistrus annectens group. This group was earlier misspelled as Pterygoplichthini...

 is sister

Cladistics

Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...

 to the tribe Ancistrini, which shares the derived

Derived

In phylogenetics, a derived trait is a trait that is present in an organism, but was absent in the last common ancestor of the group being considered. This may also refer to structures that are not present in an organism, but were present in its ancestors, i.e. traits that have undergone secondary...

 presence of an evertible patch of plates on the cheek.

Description

Most Ancistrini species (except for some Pseudancistrus

Pseudancistrus

Pseudancistrus is a genus of catfishes of the family Loricariidae.-Taxonomy:Pseudancistrus is a genus in the tribe Ancistrini of the subfamily Hypostominae. It was described by Pieter Bleeker in 1862, and redescribed by Jonathan Armbruster in 2004...

and Spectracanthicus

Spectracanthicus

Spectracanthicus is a small genus of catfish of the family Loricariidae. It includes two species, S. murinus and S. punctatissimus.-Taxonomy:...

) can be separated from all other loricariids except the Pterygoplichthyini by the presence of evertible cheek plates with hypertrophied odontode

Odontode

Odontodes, or dermal teeth, are hard structures found on the external surfaces of animals or near internal openings. They comprise a soft pulp surrounded by dentine and covered by a mineralized substance such as enamel, a structure similar to that of teeth. They generally do not have the same...

s.