''Parancistrus'' is a small

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of suckermouth armored catfishes native to

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

Taxonomy

Three species - ''Hypostomus aurantiacus'', ''H. nigricans'' and ''H. vicinus'' - were described by François Louis de la Porte, comte de Castelnau in 1855. ''Parancistrus'' was described by Pieter Bleeker in 1862 and ''P. aurantiacus'' designated as type. Later, ''P. nigricans'' and ''P. vicinus'' were deemed to be

synonyms A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

of ''P. aurantiacus'', making ''P. aurantiacus'' the only species of ''Parancistrus'' until ''P. nudiventris'' was described in 2005.

Species

There are currently two recognized species in this genus: * '' Parancistrus aurantiacus'' ( Castelnau, 1855) * '' Parancistrus nudiventris'' Rapp Py-Daniel & Zuanon, 2005

Appearance and anatomy

''Parancistrus'' is unique among loricariids due to the presence of fleshy folds on the naked area around the

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

and at the

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

points insertion in the breeding males. Breeding males also have elongated

odontode Odontodes, or dermal teeth, are hard structures found on the external surfaces of animals or near internal openings. They consist of a soft pulp surrounded by dentine and covered by a mineralized substance such as enamel, a structure similar to t ...

s on their bodies and pectoral fin spines. ''Parancistrus'' have stout bodies that are completely plated in adults. The dorsal fin membrane connects to the

adipose fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only b ...

spine. Their color is typically slate gray to black, occasionally with white streaks. They have large

gill A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow r ...

openings, which makes the genus different from all other loricariids except some '' Pogonopoma'' and '' Rhinelepis''.

References

{{Taxonbar, from=Q3363567 Ancistrini Suckermouth catfish of Brazil Catfish genera Taxa named by Pieter Bleeker Freshwater fish genera