| Phreatobius | |
|---|---|
 | |
| Phreatobius n sp | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Siluriformes |
| Family: | Heptapteridae |
| Genus: | Phreatobius Goeldi, 1905 |
| Type species | |
| Phreatobius cisternarum Goeldi, 1905 | |
Phreatobius is a genus of very small catfishes (order Siluriformes) from tropical South America.
For quite some time Phreatobius cisternarum was the only species in the genus. However, two new species were described relatively recently in 2007, Phreatobius dracunculus and Phreatobius sanguijuela. [1] [2]
Phreatobius has been classified with a number of different families: Clariidae, Plotosidae, Trichomycteridae, Cetopsidae, and Pimelodidae. Most recently, it has been classified in Heptapteridae. Its phylogenetic position remains uncertain. [3] The family placement of the genus has remained problematic and thus it is not classified in any of the existing families, [4] though Fishbase treats it as a member of Heptapteridae. [5]
An undescribed species of Phreatobius lives in waterlogged leaf litter near (not in) streams. [3] [6] Phreatobius walkeri, a nomen nudum , is provided by the Guinness Book of World Records, to describe this fish that stays on land for extended periods of time. [7] Two additional quite distinctive species of Phreatobius, as yet undescribed, are known from the Río Negro basin of Brazil. [2]
There are currently three recognized species in this genus: [8]
The three scientifically described Phreatobius species all live underground and are known only from artificial wells penetrating near-surface aquifers of the Amazon basin. [1] [2] [3] The genus has one of the widest distribution of any hypogean fish genus, with P. sanguijuela from the upper Amazon, some 2000 km from reported locations of P. cisternarum near the Amazon River mouth, and P. dracunculus also approximately 1900 km from the Rio Branco drainage area. [1] [2]
This genus can be recognized by the combination of characteristics, such as their dorsal and anal fins being continuous with a rounded caudal fin, unbranched anal fin rays, a projecting lower jaw, bright red coloration, a lack of the dorsal fin spine locking mechanism, the first pectoral fin ray being soft instead of spinous. [1] [2] Most of these traits are rare or unusual among vast groups of catfish. [3]
All three species look extremely similar. However, in P. cisternarum the eyes are tiny, while P. dracunculus and P. sanguijuela lack eyes altogether. The two eyeless species can be differentiated by fin-ray and vertebrae counts. It is also described that P. dracunculus is lighter in color, while P. cisternarum and P. sanguijuela are described as bright red. [1] [2] [3]
Catfish 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, the Mekong giant catfish from Southeast Asia, the wels catfish of Eurasia, and the piraíba of South America, to detritivores, and even to a tiny parasitic species commonly called the candiru, Vandellia cirrhosa. Neither the armour-plated types nor the naked types have scales. Despite their name, not all catfish have prominent barbels or "whiskers". Members of the Siluriformes order are defined by features of the skull and swimbladder. Catfish are of considerable commercial importance; many of the larger species are farmed or fished for food. Many of the smaller species, particularly the genus Corydoras, are important in the aquarium hobby. Many catfish are nocturnal, but others are crepuscular or diurnal.
Trichomycteridae is a family of catfishes commonly known as pencil catfishes or parasitic catfishes. This family includes the candiru fish, feared by some people for its alleged habit of entering into the urethra of humans. They are one of the few parasitic chordates. Another species is the life monsefuano which was important to the Moche culture and still an important part of Peruvian cuisine.
The Pimelodidae, commonly known as the long-whiskered catfishes, are a family of catfishes.
Listrura is a genus of pencil catfishes native to South America.
The Chiapas catfish, Lacantunia enigmatica, is an unusual species of catfish from the Usumacinta River basin in the Mexican state of Chiapas and in Guatemala. It was scientifically described in 2005 and placed in its own family Lacantuniidae. While discovery of an undescribed species of catfish is not uncommon, discovery of a new family of any vertebrate group is a rare event. The Chiapas catfish mainly feeds on crabs, prawns, small fish, and large, tough plant seeds. This catfish is commonly fished in its natural habitat, where it is known as madre de juil, which means "mother of Rhamdia".
Trichomycterus is a genus of fish in the family Trichomycteridae, the largest genus of its family with over 170 species currently described. This genus is native to freshwater habitats in Central and South America. These fish are generally small, usually about 5 to 15 cm (2–6 in) in standard length, although the largest, T. rivulatus, can reach more than twice this size. Species differ from one another primarily in body proportions, fin ray counts and colouration. Despite their relatively small size, some, such as T. punctulatus, support fisheries and are important in the local cuisine.
Microglanis is a genus of fish in the family Pseudopimelodidae native to South America. This genus has the widest distribution within its family, with species ranging from the Guianas to Venezuela; western slope of the Andes in Ecuador and Peru to the Río de La Plata basin in Argentina. They occur eastward to the Orinoco and Amazon basins. It is also present in the eastern coastal rivers of Brazil.
Phreatobius cisternarum is a species of catfish in the genus Phreatobius. This Brazilian fish is one of the few fish species that live underground in phreatic habitats. It has proved problematic in its classification.
Horabagrus is a genus of catfish in the family Horabagridae endemic to rivers in the Western Ghats in Kerala and Karnataka, India. H. brachysoma is an important food fish and members of this genus can be found in the aquarium trade.
Parotocinclus is a genus of fish in the family Loricariidae native to South America. This genus is distributed through almost all hydrographic systems in South America from the Guyana Shield drainages and Amazon Shield tributaries to the coastal drainages of eastern and southeastern Brazil, including the rio São Francisco basin. Most species have the caudal peduncle oval in cross section. It has been found that Characidium species may interact with P. maculicauda. The small Characidium will follow grazing P. maculicauda, which release particulate matter dislodged from the catfish's foraging.
Malacoglanis gelatinosus is a species of catfish of the family Trichomycteridae, and the only species of the genus Malacoglanis. This fish grows to about 2.0 centimetres (.79 in) SL. and is native to the Caquetá River basin of Colombia. Stauroglanis is the sister group to a monophyletic group formed by Malacoglanis and Sarcoglanis.
Microcambeva is a genus of catfishes of the family Trichomycteridae.
Pygidianops is a genus of pencil catfishes native to South America.
Typhlobelus is a genus of pencil catfishes native to South America.
The Sarcoglanidinae are a subfamily of catfishes of the family Trichomycteridae. It includes six genera: Ammoglanis, Malacoglanis, Microcambeva, Sarcoglanis, Stauroglanis, and Stenolicmus.
Ituglanis is a genus of small freshwater fish in the family Trichomycteridae native to South America. Their greatest diversity seems to occur in the Amazon River basin. Most species inhabit leaf litter, with several species living in caves.
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 hypogean fish.
Phreatobius dracunculus is a species of catfish in the genus Phreatobius.
Phreatobius sanguijuela is a South American species of heptapterid catfish that lives in underground waters.
Bryconops piracolina is a small fish that inhabits the waters of Brazil. It is slender and silvery in color, like many fish in Bryconops, but can be distinguished from other members by way of its dorsal fin, which has a black patch of color extending up from the fin-base; congeners usually have light pigment in the dorsal fin, or a brighter color.