The Aspredinidae are known as banjo catfishes due to their overall body shape, a depressed head and slender caudal peduncle which somewhat resembles a banjo. They occur throughout the tropical rivers of South America. Local names for aspredinids include "banjaman" or "banjo-man" (Guyana), "croncron" (French Guiana), "rabeca" (Brazil), and "guitarillo" (Venezuela). Banjo catfishes maybe found in habitats ranging from shallow backwaters to deep river channels to tidal estuaries. In general, most species are cryptically pigmented, benthic and sluggish unless disturbed. Many are semi-fossorial, during the day often resting just beneath the substrate surface.
Approximately 6O extant species of banjo catfishes have been described. A large proportion of these species are now considered subjective junior synonyms of earlier described species. As currently recognized the family contains approximately 35 nominal species placed in 13 genera. In addition there are several undescribed species mostly in the genus Bunocephalus. Despite the relatively small number of species in this family as compared to other catfish families, aspredinids are quite diverse in their morphology. They range from miniature armored species such as Hoplomyzon papillatus, less than 20 mm in length, to large elongate species such as Aspredo aspredo, reaching up to 380 mm in length.
Aspredinids are a highly derived group of catfishes and display some very unusual features. Their skin is completely keratinized and covered with tubercles. Periodically the entire outer layer of skin is shed just like that of amphibians and reptiles (Friel, 1989).
This SEM micrograph shows rows of enlarged tubercles which run longitudinally along the bodies of aspredinids. The light spots covering the tubercles are unicellular keratinized processes called unculi (Roberts, 1982). The horizontal field of view of this image is 1.68 mm.
While aspredinids can swim by typical undulatory movements, they can also use jets of water thrust from their opercular openings to skip along the substrate. When agitated, some species produce audible stridulatory sounds by repeatedly abducting and adducting their pectoral spines.
Very little is known about the general ecology of aspredinids. Based on little published work and personal observation, most aspredinids appear to be generalized omnivores and their stomachs often contain aquatic invertebrates, terrestrial insects and organic debris. One notable exception are members of the genus Amaralia. Based on stomach contents they appear to feed on the eggs of other catfishes (Friel, 1992).
Few specifics are known about reproduction of aspredinids. Parental care is known with certainty in one clade which contains Pterobunocephalus, Platystacus, Aspredo, and Aspredinichthys. Females of this clade carry their developing embryos attached to the ventral surface of their bodies. In Pterobunocephalus, the eggs are directly attached to the body whereas in Platystacus, Aspredo, and Aspredinichthys they are attached to fleshy stalks, called cotylephores, which grow out from the female (Friel, 1994). These develop seasonally and may function in the exchange of materials between the mother and her developing embryos (Wetzel, Wourms, & Friel, 1997).
List of Synonymies
|Original Description Name||Current Placement|
|Acanthobunocephalus nicoi Friel, 1995||Acanthobunocephalus nicoi|
|Agmus lyriformis Eigenmann, 1912b||Bunocephalus verrucosus|
|Aspredinichthys filamentosus Valenciennes, 1840||Aspredinichthys filamentosus|
|Aspredinichthys tibicen Valenciennes, 1840||Aspredinichthys tibicen|
|Aspredo aspredo Linnaeus, 1758||Aspredo aspredo|
|Aspredo batrachus Gronovius, 1854||Aspredo aspredo|
|Aspredo sexcirrhis Valenciennes, 1840||Platystacus cotylephorus|
|Aspredo sicuephorus Bleeker, 1858||Aspredo aspredo|
|Aspredo spectrum Gronovius, 1854||Platystacus cotylephorus|
|Bunocephalus albifasciatus Fowler, 1943||Pterobunocephalus depressus|
|Bunocephalus aleuropsis Cope, 1870||Bunocephalus aleuropsis|
|Bunocephalus amaurus Eigenmann, 1912b||Bunocephalus amaurus|
|Bunocephalus amaurus aloike Hoedeman, 1961||Bunocephalus amaurus|
|Bunocephalus amaurus sipaliwini Hoedeman, 1961||Bunocephalus amaurus|
|Bunocephalus bicolor Steindachner, 1882||Bunocephalus coracoideus|
|Bunocephalus bifidus Eigenmann, 1942||Pseudobunocephalus bifidus|
|Bunocephalus "boliviensis" Ma, 1977||Pseudobunocephalus amazonicus|
|Bunocephalus carvalhoi Miranda Ribeiro, 1944||Pseudobunocephalus iheringii|
|Bunocephalus chamaizelus Eigenmann, 1912b||Bunocephalus chamaizelus|
|Bunocephalus colombianus Eigenmann, 1912a||Bunocephalus colombianus|
|Bunocephalus coracoideus Cope, 1874||Bunocephalus coracoideus|
|Bunocephalus depressus Haseman, 1911||Pterobunocephalus depressus|
|Bunocephalus dolichurus Delsman, 1941||Pterobunocephalus dolichurus|
|Bunocephalus doriae Boulenger, 1902||Bunocephalus doriae|
|Bunocephalus "dorsolineatus" Ma, 1977||Pseudobunocephalus sp.?|
|Bunocephalus gronovii Bleeker, 1858||Bunocephalus verrucosus|
|Bunocephalus haggini Eigenmann & Allen, 1942||Bunocephalus coracoideus|
|Bunocephalus hypsiurus Kner, 1855||Amaralia hypsiura|
|Bunocephalus iheringii Boulenger, 1891||Pseudobunocephalus iheringii|
|Bunocephalus knerii Steindachner, 1882||Bunocephalus knerii|
|Bunocephalus larai von Ihering, 1930||Bunocephalus larai|
|Bunocephalus melas Cope, 1874||Bunocephalus aleuropsis|
|Bunocephalus minutus Güntert, 1942||Pseudobunocephalus iheringii|
|Bunocephalus retropinnis Eigenmann, 1942||Bunocephalus doriae|
|Bunocephalus rugosus Eigenmann & Kennedy, 1903||Pseudobunocephalus rugosus|
|Bunocephalus salathei Myers, 1927||Pseudobunocephlaus iheringii|
|Bunocephalus scabriceps Eigenmann & Eigenmann, 1889||Bunocephalus verrucosus|
|Bunocephalus "spieleri" Ma, 1977||Pseudobunocephalus sp.?|
|Cotylephorus blochii Swainson, 1838||Platystacus cotylephorus|
|Dupouyichthys sapito Schultz, 1944||Dupouyichthys sapito|
|Dysichthys amazonicus Mees, 1989||Pseudobunocephalus amazonicus|
|Dysichthys australe Eigenmann & Ward, 1907||Pseudobunocephalus rugosus|
|Dysichthys quadriradiatus Mees, 1989||Pseudobunocephalus quadriradiatus|
|Ernstichthys anduzei Fernández-Yépez, 1953||Ernstichthys anduzei|
|Ernstichthys intonsus Stewart, 1985||Ernstichthys intonsus|
|Hoplomyzon megistus Orcés, 1961||Ernstichthys megistus|
|Hoplomyzon atrizona Myers, 1942||Hoplomyzon atrizona|
|Hoplomyzon atrizona petroleus Schultz, 1944||Hoplomyzon atrizona|
|Hoplomyzon papillatus Stewart, 1985||Hoplomyzon papillatus|
|Hoplomyzon sexpapillostoma Taphorn & Marrero, 1990||Hoplomyzon sexpapilostoma|
|Micromyzon akamai Friel & Lundberg, 1996||Micromyzon akamai|
|Platystacus cotylephorus Bloch, 1794||Platystacus cotylephorus|
|Platystacus laevis Bloch, 1794||Aspredo aspredo|
|Platystacus nematophorus Bleeker, 1862||Platystacus cotylephorus|
|Platystacus verrucosus Bloch, 1794||Bunocephalus verrucosus|
|Pseudobuncephalus lundbergi Friel 2008 ||Pseudobuncephalus lundbergi|
|Siluris hexdactylus La Cepede, 1803||Platystacus cotylephorus|
|Siluris verrucosus Walbaum, 1792||Bunocephalus verrucosus|
|Xyliphius barbatus de Arámburu & Arámburu, 1962||Xyliphius barbatus|
|Xyliphius kryptos Taphorn & Lilyestrom, 1983||Xyliphius kryptos|
|Xyliphius lepturus Orcés, 1962||Xyliphius lepturus|
|Xyliphius lombarderoi Risso & Risso, 1964||Xyliphius lombarderoi|
|Xyliphius magdalenae Eigenmann, 1912a||Xyliphius magdalenae|
|Xyliphius melanopterus Orcés, 1962||Xyliphius melanopterus|
This Neotropical family of catfishes is found throughout the tropical rivers of South America (Magdalena, Orinoco, Amazon, São Francisco and Paraguay-Paraná), a few rivers west of the Andes (Atrato, San Juan, and Patia) and in brackish and marine waters between the Orinoco and Amazon River deltas.
Evolution and Systematics
Discussion of Phylogenetic Relationships
modified from Friel (1994).
As already mentioned, aspredinids are highly derived catfishes and their monophyly is well supported by many apomorphies. Some of these including: laminar processes of the pterotics directed laterally; vomer absent; mandibular lateralis canal does not enter lower jaw; opercle "L" shaped, resembles a branchiostegal ray; opercular apertures reduced to ventral slits; 5 or fewer branchiostegal rays; dorsal lamina of Weberian complex contacts dorsal surface of body; hemal canal forms de novo by vertebra 7 without a transformation series of rib parapophyses; abdominal vertebral with peg and socket articulations; parapophyses for ribs reduced or absent; 10 or fewer principal caudal-fin rays; expanded bases on outermost caudal-fin rays; muscles on the ventral surface of the pectoral girdle highly reduced or absent; basipterygia without anterior arms; posterior cartilage of basipterygia reduced; mental barbel bases reduced; rows of unculiferous tubercle present on body; and loss of alarm cells & fright reaction. For a complete list of synapomorphies see Friel (1994).
Friel's (1994) phylogenetic revision of the aspredinids revealed that the traditionally recognized subfamily Aspredininae is not the sister group to all other Aspredinidae but is nested higher up in the phylogeny of aspredinids. Furthermore, the subfamily Bunocephalinae sensu Myers (1960), tribe Bunocephalini sensu Myers (1960), Dysichthys sensu Mees (1988, 1989) and Aspredo sensu Mees (1987) are paraphyletic taxa. Major taxonomic and nomenclatural changes are necessitated as a result of this new phylogeny. Species originally placed in Bunocephalus Kner, 1855 and recently transferred to Dysichthys Cope, 1874 by Mees (1988, 1989) are reassigned to Pseudobunocephalus Friel 2008, Pterobunocephalus Fowler, 1943, and Bunocephalus Kner, 1855. In addition, several genera are synonymized. Petacara Böhlke, 1959 is a junior subjective synonym of Pterobunocephalus Fowler, 1943; Dysichthys Cope, 1874 is a junior subjective synonym of Bunocephalus Kner, 1855; and Bunocephalichthys Bleeker 1858 and Agmus Eigenmann, 1910 are junior objective synonyms of Bunocephalus Kner, 1855.
The phylogenetic relationship of the Aspredinidae to other catfishes remains controversial. Prior ideas on relationships are briefly summarized. Günther (1864) first suggested a relationship between the Aspredinidae and a clade containing the Neotropical loricarioids and the Asian Sisoridae. A relationship with loricarioid catfishes was also suggested by Chardon (1968). However Baskin (1972) and Howes (1983) both reviewed Chardon's evidence and concluded that the Aspredinidae are not closely related to loricarioids. Ferraris (1989) suggested that the Asian Akysidae are the sister group to the Aspredinidae. Mo (1991) placed the Aspredinidae either basal to or in a polytomy with a clade containing the Afro-Asian Clariidae, the African Amphiliidae, Neotropical loricarioids, and Asian sisoroids (Amblycipitidae, Akysidae and Sisoridae). Pinna (1993) placed the Aspredinidae in a polytomy with Amblycipitidae, Akysidae, Sisoridae, Amphiliidae and loricarioids. Chen (1994) placed the Aspredinidae as the sister group to Asian sisoroids. More recently, Pinna (1996) now places the Aspredinidae within the currently recognized Asian Sisoridae. Friel (unpublished) reanalyzes all prior evidence presented by others along with new character information and finds two equally parsimonious placements for the Aspredinidae. The sister group to the Aspredinidae are either the Asian sisoroid catfishes as has been suggested by others or the doradoid catfishes (the African Mochokidae, and the Neotropical Doradidae, Centromochlidae and Auchenipteridae). A most recent molecular phylogney (Sullivan et al. 2006) supports the hypothesis that aspredinids are the sistergroup to a clade containing the Neotropical Auchenipteridae and Doradidae.
Molecular Biology and Genetics
Statistics of barcoding coverage
Specimen Records: 30
Specimens with Sequences: 28
Specimens with Barcodes: 21
Species With Barcodes: 11
Public Records: 15
Public Species: 9
Public BINs: 9
Aspredinids are found throughout the major tropical rivers of South America (e.g., Magdalena, 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 Patía Rivers.
Of the 13 genera in the family Aspredinidae, a few genera have been described relatively recently, including Acanthobunocephalus in 1995, Micromyzon in 1996, and Pseudobunocephalus in 2008. These genera are categorized into three subfamilies.
The Aspredinidae are often recognized as a part of the primarily Asian 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.
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 banjo. Banjo catfishes lack an adipose fin. Most species lack the dorsal spine-locking mechanism. Though their bodies are scaleless, their skin is completely keratinized and is covered by large, unculiferous tubercles 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.
Aspredinids live in a variety of habitats ranging from shallow backwaters to deep river channels to tidal estuaries. Some aspredinids appear to be semifossorial, 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 omnivores that feed on aquatic and terrestrial invertebrates 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. Because these catfish live in muddy environments, this behaviour has been hypothesised to give 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 American 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 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.
|Wikimedia Commons has media related to Aspredinidae.|
|Wikispecies has information related to: Aspredinidae|
- Froese, Rainer, and Daniel Pauly, eds. (2011). "Aspredinidae" in FishBase. December 2011 version.
- Nelson, Joseph S. (2006). Fishes of the World. John Wiley & Sons, Inc. ISBN 0-471-25031-7.
- Friel, John P. (2008). "Pseudobunocephalus, a new genus of banjo catfish with the description of a new species from the Orinoco River system of Colombia and Venezuela (Siluriformes: Aspredinidae)". Neotropical Ichthyology 6 (3): 293–300. doi:10.1590/S1679-62252008000300001.
- Friel, John Patrick (1994-12-13). A Phylogenetic Study of the Neotropical Banjo Catfishes (Teleostei: Siluriformes: Aspredinidae) (PDF). Duke University, Durham, NC. Retrieved 2007-08-07.
- Friel, J (1995). "Acanthobunocephalus nicoi, a new genus and species of miniature banjo-catfish from the upper Orinoco and Casiquiare Rivers, Venezuela. (Siluriformes: Aspredinidae)". Ichthyological Exploration of Freshwaters 6 (1): 89–95.
- Friel, John P.; Lundberg, John G. (Aug 1, 1996). "Micromyzon akamai, Gen. et Sp. Nov., a Small and Eyeless Banjo Catfish (Siluriformes: Aspredinidae) from the River Channels of the Lower Amazon Basin". Copeia 1996 (3): 641–648. doi:10.2307/1447528. JSTOR 1447528.
- Ferraris, Carl J., Jr. (2007). "Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types" (PDF). Zootaxa 1418: 1–628. Retrieved 2009-06-24.
- Sullivan, JP; Lundberg JG; Hardman M (2006). "A phylogenetic analysis of the major groups of catfishes (Teleostei: Siluriformes) using rag1 and rag2 nuclear gene sequences". Mol Phylogenet Evol. 41 (3): 636–62. doi:10.1016/j.ympev.2006.05.044. PMID 16876440.
- Sands D.: South American Catfishes, Interpet 1988, ISBN 0-86101-348-4
- Monks N. (editor): Brackish Water Fishes, TFH 2006, ISBN 0-7938-0564-3
- Froese, Rainer and Pauly, Daniel, eds. (2007). "Platystacus cotylephorus" in FishBase. Aug 2007 version.
- Editore, Arnoldo. Freshwater and Marine Aquarium Fishes. New York: Simon and Schuster 1976, ISBN 0-671-22809-9
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