Aspredinidae
Encyclopedia
The Aspredinidae are a small South America
n family
of catfish
es (order
Siluriformes) also known as the banjo catfishes.
, Orinoco
, Amazon
, São Francisco
, Paraguay
-Paraná
, and Uruguay
). Bunocephalus
is the only genus found in rivers west of the Andes
including the Atrato
, San Juan
, and Patia River
s.
in the family Aspredinidae. A few of these genera have been described relatively recently, including Acanthobunocephalus in 1995, Micromyzon in 1996, and Pseudobunocephalus
in 2008. These genera are categorized into three subfamilies. Pseudobunocephalus, the most recently described genus, is the most basal
genus in the family; it was not assigned to any of the three subfamilies.
Aspredinidae is often recognized as a part of the primarily Asia
n superfamily Sisoroidea
as the sister group
to the family Erethistidae
. However, other authors find that they are sister to the superfamily Doradoidea, which includes Doradidae
, Auchenipteridae, and perhaps Mochokidae
.
. Banjo catfishes lack an adipose fin. Most species lack the dorsal spine-locking mechanism. Though their bodies are scaleless, their skin is completely keratin
ized and is covered by large, unculiferous tubercle
s arranged in longitudinal rows; the entire outer layer of skin may be shed. Size ranges from less than 2.0 centimetres (.79 in) SL
in Hoplomyzon papillatus
to Aspredo aspredo
at about 38 centimetres (15 in) SL
, though most are less than 15 cm. Most species exhibit cryptic coloration. Aspredinids have a loss of alarm cells and the fright reaction that is present in other ostariophysans
.
Sexual dimorphism
is exhibited in most species in that mature females are typically larger than males; this is, however, reversed in Hoplomyzon sexpapilostoma
. Also, in Aspredo and Platystacus the dorsal fin spine is much longer in males than in females.
, during the day often resting slightly buried in leaf litter or other soft substrates. Members of the subfamily Aspredininae inhabit coastal rivers and brackish water habitats such as mangrove swamps.
In general, most species are cryptically pigmented, benthic
, and rather sluggish unless disturbed. Like most fish, they are able to swim by undulating their bodies; however, they also propel themselves by pumping water through their gill openings to skip along the substrate. Some species are able to produce sounds by moving their pectoral fin spines back and forth when they are agitated. Most aspredinids are generalized omnivore
s that feed on aquatic and terrestrial invertebrate
s and organic debris; however, members of Amaralia appear to specialize in feeding on the eggs of other catfishes.
A peculiarity of the catfishes in the subfamily Aspredininae is that after the female's eggs are fertilised by the male, she attaches them to her belly and carries them to shallow water to hatch. In Pterobunocephalus, the eggs are directly attached to the body, while in the other three genera of the subfamily, the eggs are attached to cotylephores, which are fleshy stalks that develop seasonally on the underside of the body that may function in exchange of materials between the mother and her developing embryos. It has been hypothesised that because these catfish live in muddy environments, this behaviour gives the eggs better access to oxygenated water.
Accounts of reproduction in Bunocephalus vary; some sources state that they are egg-scatterers without any parental care, while others note them to build a depression for a nest and guard the eggs.
n fish, preferring slightly acidic, not too hard water maintained at 20–25°C (68–77°F). Since these species are nocturnal burrowers, they need an aquarium with a soft, sandy substrate into which they will hide during the daytime and forage in at night. Sharp sand or coarse gravel will damage their whiskers. Although not schooling
fish they are tolerant of their own kind and also get along with other small aquarium species.
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
n family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of catfish
Catfish
Catfishes 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 heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...
es (order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Siluriformes) also known as the banjo catfishes.
Distribution
Aspredinids are found throughout the major tropical rivers of South America (e.g., MagdalenaMagdalena River
The Magdalena River is the principal river of Colombia, flowing northward about through the western half of the country. It takes its name from the biblical figure Mary Magdalene. It is navigable through much of its lower reaches, in spite of the shifting sand bars at the mouth of its delta, as...
, Orinoco
Orinoco
The Orinoco is one of the longest rivers in South America at . Its drainage basin, sometimes called the Orinoquia, covers , with 76.3% of it in Venezuela and the remainder in Colombia...
, Amazon
Amazon River
The Amazon of South America is the second longest river in the world and by far the largest by waterflow with an average discharge greater than the next seven largest rivers combined...
, São Francisco
São Francisco River
The São Francisco is a river in Brazil. With a length of , it is the longest river that runs entirely in Brazilian territory, and the fourth longest in South America and overall in Brazil...
, Paraguay
Paraguay River
The Paraguay River is a major river in south central South America, running through Brazil, Bolivia, Paraguay, and Argentina...
-Paraná
Paraná River
The Paraná River is a river in south Central South America, running through Brazil, Paraguay and Argentina for some . It is second in length only to the Amazon River among South American rivers. The name Paraná is an abbreviation of the phrase "para rehe onáva", which comes from the Tupi language...
, and Uruguay
Uruguay River
The Uruguay River is a river in South America. It flows from north to south and makes boundary with Brazil, Argentina, and Uruguay, separating some of the Argentine provinces of the Mesopotamia from the other two countries...
). Bunocephalus
Bunocephalus
Bunocephalus is a genus of catfishes of the family Aspredinidae. Currently not a natural grouping, Bunocephalus contains species of an undescribed genus Pseudobunocephalus. B...
is the only genus found in rivers west of the Andes
Andes
The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...
including the Atrato
Atrato River
The Río Atrato is a river of northwestern Colombia. It rises in the slopes of the Western Cordillera and flows almost due north to the Gulf of Urabá , where it forms a large, swampy delta....
, San Juan
San Juan River (Colombia)
San Juan River is an important river of Colombia. It quoted source is in the Cordillera Occidental and has a length of 380 km...
, and Patia River
Patía River
The Patía River is a river in southwestern Colombia. It flows over 400 kilometers to drain into the Pacific Ocean north of Tumaco. The Patía River is the longest river on the Colombian Pacific Coast. The last 90 kilometers is navigable by boat.-Geography:...
s.
Taxonomy
There are 13 generaGenus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
in the family Aspredinidae. A few of these genera have been described relatively recently, including Acanthobunocephalus in 1995, Micromyzon in 1996, and Pseudobunocephalus
Pseudobunocephalus
Pseudobunocephalus is a genus of catfishes of the family Aspredinidae.-Taxonomy:The species of Pseudobunocephalus were originally classified in the genus Bunocephalus, but after further study it was found that these fish were unrelated to the type species Bunocephalus verrucosus or any of the...
in 2008. These genera are categorized into three subfamilies. Pseudobunocephalus, the most recently described genus, is the most basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
genus in the family; it was not assigned to any of the three subfamilies.
Aspredinidae is often recognized as a part of the primarily Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
n superfamily Sisoroidea
Sisoroidea
Sisoroidea is a superfamily of catfishes . It contains the four families Amblycipitidae, Akysidae, Sisoridae, and Erethistidae; many sources also include Aspredinidae. With Aspredinidae, this superfamily includes about 42 genera and 230 species.-Taxonomy:Sisoroidea is sister to the Loricarioidea...
as the sister group
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
to the family Erethistidae
Erethistidae
Erethistidae are a family of catfishes that originate from southern Asia.-Taxonomy:This family includes species previously placed in Sisoridae. They were removed because they were thought to be more closely related to the neotropical Aspredinidae than to the remaining sisorids due to a number of...
. However, other authors find that they are sister to the superfamily Doradoidea, which includes Doradidae
Doradidae
Doradidae is a family of catfishes also known as thorny catfishes or talking catfishes. These fish are native to South America, primarily in Brazil, Peru, and the Guianas.Doradids are omnivorous.-Taxonomy:...
, Auchenipteridae, and perhaps Mochokidae
Mochokidae
The Mochokidae are a family of catfishes that are known as the squeakers and upside-down catfish. There are 10 genera and about 188 species of mochokids. All the mochokids are freshwater species originating from Africa....
.
Description
The common name of the family "banjo catfishes" refers to their overall body shape, with a depressed head and slender caudal peduncle, that in some species gives the appearance of a banjoBanjo
In the 1830s Sweeney became the first white man to play the banjo on stage. His version of the instrument replaced the gourd with a drum-like sound box and included four full-length strings alongside a short fifth-string. There is no proof, however, that Sweeney invented either innovation. This new...
. Banjo catfishes lack an adipose fin. Most species lack the dorsal spine-locking mechanism. Though their bodies are scaleless, their skin is completely keratin
Keratin
Keratin refers to a family of fibrous structural proteins. Keratin is the key of structural material making up the outer layer of human skin. It is also the key structural component of hair and nails...
ized and is covered by large, unculiferous tubercle
Tubercle
A tubercle is generally a wart-like projection, but it has slightly different meaning depending on which family of plants or animals it is used to refer to....
s arranged in longitudinal rows; the entire outer layer of skin may be shed. Size ranges from less than 2.0 centimetres (.79 in) SL
Fish measurement
Fish measurement refers to the measuring of the length of individual fish and of various parts of their anatomy. These data are used in many areas of ichthyology, including taxonomy and fisheries biology.-Overall length:...
in Hoplomyzon papillatus
Hoplomyzon papillatus
Hoplomyzon papillatus is a species of catfish of family Aspredinidae....
to Aspredo aspredo
Aspredo aspredo
Aspredo aspredo is the only species of catfish in the genus Aspredo of the family Aspredinidae.This species originates from the lower portions of rivers from Venezuela to northern Brazil. It occurs in the Orinoco delta, through the Guianas, to the Amazon River.A...
at about 38 centimetres (15 in) SL
Fish measurement
Fish measurement refers to the measuring of the length of individual fish and of various parts of their anatomy. These data are used in many areas of ichthyology, including taxonomy and fisheries biology.-Overall length:...
, though most are less than 15 cm. Most species exhibit cryptic coloration. Aspredinids have a loss of alarm cells and the fright reaction that is present in other ostariophysans
Ostariophysi
Ostariophysi is the second-largest superorder of fish. Members of this superorder are called ostariophysians. This diverse group contains almost 8,000 species, about 28% of known fish species in the world and 68% of freshwater species, and are present on all major continents except Antarctica...
.
Sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
is exhibited in most species in that mature females are typically larger than males; this is, however, reversed in Hoplomyzon sexpapilostoma
Hoplomyzon sexpapilostoma
Hoplomyzon sexpapilostoma is a species of catfish of family Aspredinidae....
. Also, in Aspredo and Platystacus the dorsal fin spine is much longer in males than in females.
Ecology
Aspredinids live in a variety of habitats ranging from shallow backwaters to deep river channels to tidal estuaries. Some aspredinids appear to be semi-fossorialFossorial
A fossorial organism is one that is adapted to digging and life underground such as the badger, the naked mole rat, and the mole salamanders Ambystomatidae...
, during the day often resting slightly buried in leaf litter or other soft substrates. Members of the subfamily Aspredininae inhabit coastal rivers and brackish water habitats such as mangrove swamps.
In general, most species are cryptically pigmented, benthic
Benthos
Benthos is the community of organisms which live on, in, or near the seabed, also known as the benthic zone. This community lives in or near marine sedimentary environments, from tidal pools along the foreshore, out to the continental shelf, and then down to the abyssal depths.Many organisms...
, and rather sluggish unless disturbed. Like most fish, they are able to swim by undulating their bodies; however, they also propel themselves by pumping water through their gill openings to skip along the substrate. Some species are able to produce sounds by moving their pectoral fin spines back and forth when they are agitated. Most aspredinids are generalized omnivore
Omnivore
Omnivores are species that eat both plants and animals as their primary food source...
s that feed on aquatic and terrestrial invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s and organic debris; however, members of Amaralia appear to specialize in feeding on the eggs of other catfishes.
A peculiarity of the catfishes in the subfamily Aspredininae is that after the female's eggs are fertilised by the male, she attaches them to her belly and carries them to shallow water to hatch. In Pterobunocephalus, the eggs are directly attached to the body, while in the other three genera of the subfamily, the eggs are attached to cotylephores, which are fleshy stalks that develop seasonally on the underside of the body that may function in exchange of materials between the mother and her developing embryos. It has been hypothesised that because these catfish live in muddy environments, this behaviour gives the eggs better access to oxygenated water.
Accounts of reproduction in Bunocephalus vary; some sources state that they are egg-scatterers without any parental care, while others note them to build a depression for a nest and guard the eggs.
In the aquarium
A few banjo catfishes are kept as aquarium fish, predominantly the smaller members of the subfamily Aspredininae. Their requirements are similar to those of other tropical South AmericaSouth America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
n fish, preferring slightly acidic, not too hard water maintained at 20–25°C (68–77°F). Since these species are nocturnal burrowers, they need an aquarium with a soft, sandy substrate into which they will hide during the daytime and forage in at night. Sharp sand or coarse gravel will damage their whiskers. Although not schooling
Shoaling and schooling
In biology, any group of fish that stay together for social reasons are said to be shoaling , and if, in addition, the group is swimming in the same direction in a coordinated manner, they are said to be schooling . In common usage, the terms are sometimes used rather loosely...
fish they are tolerant of their own kind and also get along with other small aquarium species.
Further reading
- Editore, Arnoldo. Freshwater and Marine Aquarium Fishes. Simon and Shuster, New York, NY, 1976.