''Acanthicus hystrix'', the lyre-tail pleco, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

armored catfish Armoured catfish may refer to: *Family Loricariidae: The armoured suckermouth catfish, also known as suckermouth catfish, armoured catfish or simply 'plecs' or 'plecos' *Family Callichthyidae: armoured catfish, includes the genera **''Corydoras'', ...

native to the

Amazon Amazon most often refers to: * Amazons, a tribe of female warriors in Greek mythology * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon River, in South America * Amazon (company), an American multinational technology c ...

Tocantins Tocantins () is one of the 26 states of Brazil. It is the newest state, formed in 1988 and encompassing what had formerly been the northern two-fifths of the state of Goiás. Tocantins covers and had an estimated population of 1,496,880 in 20 ...

– Araguaia and

Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers , with 76.3 percent of it in Venezuela and the remainder in Colombia. It is the fourth largest river in the wo ...

basins.Chamon, C.C. (2016): Redescription of ''Acanthicus hystrix'' Agassiz, 1829 (Siluriformes: Loricariidae), with comments on the systematics and distribution of the genus. ''Zootaxa, 4088 (3): 395–408.'' It is typically found at various depths on a rock or rock–gravel bottom in the main channel of rivers in places with moderate to strong current, although it also occurs in slow currents. The species is occasionally seen in the aquarium trade, but its adult size and territorially aggressive behavior means that a very large tank is required.

Appearance

It grows to in

standard length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish ...

, but may possibly reach . Its color ranges from medium-brown to near-black (especially those from the

Madeira ) , anthem = ( en, "Anthem of the Autonomous Region of Madeira") , song_type = Regional anthem , image_map=EU-Portugal_with_Madeira_circled.svg , map_alt=Location of Madeira , map_caption=Location of Madeira , subdivision_type=Sovereign st ...

, Branco and Xingu rivers are dark), and the underparts often have a vermiculated pattern. Some of the variants are commonly considered as separate,

undescribed species In taxonomy, an undescribed taxon is a taxon (for example, a species) that has been discovered, but not yet formally described and named. The various Nomenclature Codes specify the requirements for a new taxon to be validly described and name ...

in the aquarium trade (e.g., L193 from the Orinoco basin and L407 from the Branco basin; in the

L-number The L-number system is a semi-scientific classification system of catfish based on photographs of shipments of tropical catfish of the family Loricariidae published by the German aquarium magazine DATZ (Die Aquarien- und Terrarienzeitschrift (The ...

system), but there is extensive overlap in the

morphometrics Morphometrics (from Greek μορϕή ''morphe'', "shape, form", and -μετρία ''metria'', "measurement") or morphometry refers to the quantitative analysis of ''form'', a concept that encompasses size and shape. Morphometric analyses are co ...

of the different populations. Unlike the

polka dot lyre-tail pleco ''Acanthicus adonis'', the adonis pleco or polka dot lyre-tail pleco, is a large species of armored catfish.PlanetCatfish: Acanthicus adonis.' Retrieved 17 May 2013 It was originally described from the lower Tocantins River in Brazil, but individ ...

(''A. adonis''), ''A. hystrix'' never has white spots. Adults males are especially spiny with extensive

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 th ...

s on the cheeks and

opercle The operculum is a series of bones found in bony fish and chimaeras that serves as a facial support structure and a protective covering for the gills; it is also used for respiration and feeding. Anatomy The opercular series contains four bo ...

References

Ancistrini Catfish of South America Fish of the Amazon basin Freshwater fish of Brazil Freshwater fish of Peru Fish described in 1829 Taxa named by Achille Valenciennes {{Loricariidae-stub