''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 Loricariidae is the largest family of catfish (order Siluriformes), with 92 genera and just over 680 species. Loricariids originate from freshwater habitats of Costa Rica, Panama, and tropical and subtropical South America. These fish are not ...

. 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 sever ...

of the species was collected in the

Solimões River Solimões () is the name often given to upper stretches of the Amazon River in Brazil from its confluence with the Rio Negro upstream to the border of Peru. Geography The Amazon / Solimões river just above the confluence of the Solimões and ...

, upstream of its confluence with the

Purus River The Purus River (Portuguese: ''Rio Purus''; Spanish: ''Río Purús'') is a tributary of the Amazon River in South America. Its drainage basin is , and the mean annual discharge is . The river shares its name with the Alto Purús National Park and ...

. This species has been known in the aquarium trade, at least since 1992, as papa panaque or under the L-number code L090. It reaches up to about in length. This species, '' Peckoltia pankimpuju'', '' Panaqolus nix'', '' Loricaria spinulifera'' 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 Cavefish or cave fish is a generic term for fresh and brackish water fish adapted to life in caves and other underground habitats. Related terms are subterranean fish, troglomorphic fish, troglobitic fish, stygobitic fish, phreatic fish and ...

), 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