Pterygoplichthyini
Encyclopedia
Pterygoplichthyini is a tribe
of catfish
es (order
Siluriformes) 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. Pterygoplichthyines are known from nearly the entire range of loricariids except for the Guyanas
and coastal streams in southeastern Brazil
.
Pterygoplichthyini is sister
to the tribe Ancistrini
, which shares the derived
presence of an evertible patch of plates on the cheek.
Pterygoplichthys and the H. annectens group differ most obviously in the number of dorsal fin rays (7 in the H. annectens group and 9+ in Pterygoplichthys). The two genera are supported as sisters by only one derived characteristic: a modified stomach that is attached to the abdominal wall by a net of connective tissue.
This modified stomach allows these fish to breathe air. The stomach is vascularized. A white net of connective tissue surrounds the organ, leaving a circular area in the middle of the stomach free; this connective tissue firmly holds the stomach to the body wall and is better developed in adults. It may also function as a hydrostatic organ, allowing the fish to remain buoyant midwater.
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...
. It includes two genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
, Pterygoplichthys
Pterygoplichthys
Pterygoplichthys is a genus of the armored catfish family Loricariidae. These fish are commonly known as sailfin armoured catfish or sailfin plecs.-Taxonomy:This genus was described in 1858 by Theodore Nicholas Gill...
and the currently undescribed genus referred to as the Hemiancistrus annectens group. This group was earlier misspelled as Pterygoplichthini. Pterygoplichthyines are known from nearly the entire range of loricariids except for the Guyanas
Guyanas
Guyana is a country in South America.Guyana, Guayana, or Guiana may also refer to:*Guayana Esequiba, the territory of Guyana claimed by Venezuela*Guayana Region, an administrative region of Venezuela...
and coastal streams in southeastern Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
.
Pterygoplichthyini 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
Ancistrini
Ancistrini is a tribe of catfishes of the family Loricariidae.-Taxonomy:Ancistrini has previously been considered a loricariid subfamily. However, it was realized that the subfamily Hypostominae would be paraphyletic if Ancistrinae continued to be recognized...
, 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.
Pterygoplichthys and the H. annectens group differ most obviously in the number of dorsal fin rays (7 in the H. annectens group and 9+ in Pterygoplichthys). The two genera are supported as sisters by only one derived characteristic: a modified stomach that is attached to the abdominal wall by a net of connective tissue.
This modified stomach allows these fish to breathe air. The stomach is vascularized. A white net of connective tissue surrounds the organ, leaving a circular area in the middle of the stomach free; this connective tissue firmly holds the stomach to the body wall and is better developed in adults. It may also function as a hydrostatic organ, allowing the fish to remain buoyant midwater.