''Panaque bathyphilus'' is an Amazonian

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 ...

of armoured

catfish Catfish (or catfishes; order Siluriformes or Nematognathi) 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 three largest species alive, ...

from the family Loricariidae. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

of the species was collected in the Solimões River, upstream of its

confluence In geography, a confluence (also: ''conflux'') occurs where two or more flowing bodies of water join to form a single channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river (main stem); o ...

with the Purus River. This species has been known in the aquarium trade, at least since 1992, as papa panaque or under 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 ...

code L090. It reaches up to about in length. This species, ''

Peckoltia pankimpuju ''Peckoltia pankimpuju'' is a species of armored catfish from the family Loricariidae, native to the Marañón River in the upper Amazon basin of Peru. It is commonly called the coal pleco, Peruvian lyre-tail, and L350 under the L-number, L-numbe ...

'', ''

Panaqolus nix ''Panaqolus nix'' is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the Madeira River and the Mamoré River in Brazil, as well as the Madre de Dios River drainage basin in Peru. It is reported t ...

'', ''

Loricaria spinulifera ''Loricaria spinulifera'' is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the Rio Negro basin in Brazil, including the Branco River and the Jauaperi River. It is typically seen in deep chann ...

'' and '' L. pumila'' are the only loricariid catfish species known to occur in a deep water form with reduced pigment and eyes (similar to cavefish), and another "normal" form in shallower waters. ''P. bathyphilus'' and a few other loricariid catfish species of the mainstream of large South American rivers have greatly elongated streamers on their tail. It is speculated that this may serve as an early warning system against the large predatory catfish that also roam their habitat. Positioned with the head towards the water current, as typical of loricariid catfish, the long tail streamers of ''P. bathyphilus'' are the first to be contacted by a large predator that hunts against the current, perhaps allowing it to escape.

References

{{Taxonbar, from=Q6409736 Ancistrini Catfish of South America Endemic fauna of Brazil Fish of the Amazon basin Freshwater fish of Brazil Environment of Amazonas (Brazilian state) Fish described in 2008 Taxa named by Nathan Keller Lujan