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Banjo Catfishes

John P. Friel
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taxon links [up-->]Acanthobunocephalus [up-->]Aspredo [up-->]Micromyzon [up-->]Platystacus [up-->]Bunocephalus [up-->]Pterobunocephalus [up-->]Pseudobunocephalus [up-->]Amaralia [up-->]Dupouyichthys [up-->]Hoplomyzon [up-->]Xyliphius [up-->]Aspredinichthys [up-->]Ernstichthys [down<--]Siluriformes Interpreting the tree
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modified from Friel (1994).

Containing group: Siluriformes


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).

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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).

Discussion of Phylogenetic Relationships

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.

Geographic Distribution

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.

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Key to Genera

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

Other Names for Aspredinidae


Baskin, J. N. 1972. Structure and relationships of the Trichomycteridae. Ph.D. thesis, City University of New York, XXI + 389 pp.

Böhlke, J. E. 1959. Results of the Catherwood Foundation Peruvian Amazon expedition. Petacara, a new genus for the bunocephalid catfish, Bunocephalus dolichurus Delsman. Notulae Naturae, 318: 1-6.

Chardon, M. 1968. Anatomie comparée de l'appareil de Weber et des structures connexes chez les Siluriformes. Annales de Muse Royale de l'Afrique Centrale, Ser. 8, Sciences Zoologiques, 169: 1-227.

Chen, X. 1994. Phylogenetic studies of the amblycipitid catfishes (Teleostei, Siluriformes) with species accounts. Ph.D. thesis, Duke University, XX + 471 pp.

Cope, E. D. 1874. On some Batrachia and Nematognathi brought back from the upper Amazon by Prof. Orton. Proceedings of the Academy of Natural Sciences of Philadelphia, 120-137.

Eigenmann, C. H. 1910. Catalogue of the fresh-water fishes of tropical and South America. Reports of the Princeton University Expeditions to Patagonia, 1896-1899, 3(2):375-484.

Ferraris, C. 1989. On the interrelationships between the Aspredinidae and the Akysidae (Ostariophysi, Siluriformes). Abstracts of the 1989 Annual Meeting of the American Society of Ichthyologists and Herpetologists at San Francisco StateUniversity, p. 86.

Fowler, H. W. 1943. Zoological results of the second Bolivian expedition for the Academy of Natural Sciences of Philadelphia 1936-1937. Part II. - Additional new fishes. Notulae Naturae,(120): 1-7.

Friel, J. P. 1989. Epidermal keratinization and molting in the banjo catfishes (Siluriformes: Aspredinidae). Abstracts of the 1989 Annual Meeting of the American Society of Ichthyologists and Herpetologists at San Francisco State University, p. 89.

Friel, J. P. 1992. A phylogenetic revision of Amaralia, a genus of oophagous banjo catfishes. Abstracts of the 1992 Annual Meeting of the American Society of Ichthyologists and Herpetologists at the University of Illinois at Urbana-Champaign, p. 104.

Friel, J. P. 1994. A phylogenetic study of the Neotropical banjo catfishes (Teleostei: Siluriformes: Aspredinidae) Ph.D.thesis, Duke University, Durham, NC, 256 pp.

Friel, J. P. 1995. Acanthobunocephalus nicoi, a new genus and species of miniature banjo-catfish from the upper Orinoco and Casiquiare Rivers, Venezuela. (Siluriformes: Aspredinidae). Ichthyological Explorations of Freshwaters, 6(1): 89-95.

Friel, J. 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.

Friel, J. P. & Lundberg, J. G. 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.

Günther, A. 1864. Catalogue of the Physostomi, containingthe families Siluridae, Characinidae, Haplochitonidae, Sternoptychidae, Scopelidae, Stomiatidae in the collection of the British Museum. Vol. 5, British Museum, London, XXII+ 455 pp.

Howes, G. J. 1983. The cranial muscles of loricarioid catfishes, their homologies and value as taxonomic characters (Teleostei: Siluroidei). Bulletin of the British Museum of Natural History, (Zoology), 45(6): 309-345.

Kner, R. 1855 . Ichthyologische Beiträge. I. Über die Gattungen Aspredo und Chaca C. V. aus der Familie der Welse (Siluroidei). Sitzungsberichte der Mathematisch- Naturwissenschaftlichen Classe der Kaiserlichen Akademie der Wissenschaften, 8: 92-105.

Mees, G. F. 1987. The members of the subfamily Aspredininae, family Aspredinidae in Suriname (Pisces, Nematognathi). Proceedings of the Koninklijke Nederlandse Akademie van Wetenschappen, 90(2): 173-192.

Mees, G. F. 1988. The genera of the subfamily Bunocephalinae (Pisces, Nematognathi, Aspredinidae). Proceedings of the Koninklijke Nederlandse Akademie van Wetenschappen, 91(1):85-102.

Mees, G. F. 1989. Notes on the genus Dysichthys, subfamily Bunocephalinae, family Aspredinidae (Pisces, Nematognathi). Proceedings of the Koninklijke Nederlandse Akademie van Wetenschappen, 92(2): 189-250.

Mo, T. 1991. Anatomy, relationships and systematics of the Bagridae (Teleostei: Siluroidei) with a hypothesis of siluroid phylogeny. Theses Zoologicae 17, Koeltz Scientific Books, Koenigstein, vii + 216 pp., 63 figs.

Myers, G. S. 1960. The genera and ecological geography of the South American banjo catfishes, family Aspredinidae. Stanford Ichthyological Bulletin, 7(4): 132-139.

Pinna, M. C. C. 1993. Higher-level phylogeny of Siluriformes, with a new classification of the order (Teleostei, Ostariophysi). Ph.D. thesis, The City University of New York,xi + 482 pp.

Pinna, M. C. C. 1996. A phylogenetic analysis of the Asian catfish families Sisoridae, Akysidae and Amblycipitidae, with a hypothesis on the relationships of the neotropical Aspredindae (Teleostei, Ostariophysi). Fieldiana. No. 4:1-83.

Sullivan, J. P., Lundberg, J. G. and Hardman, M.. 2006. A phylogenetic analysis of the major groups of catfishes (Teleostei: Siluriformes) using rag1 and rag2 nuclear gene sequences, Molecular Phylogenetics and Evolution, 41(3): 636-662.

Wetzel, J., Wourms, J. and Friel, J. 1977. Modifications of the skin epidermis in the skin-brooding catfish, Platystacus cotylephorus. Environmental Biology of Fishes 50(1):13-25.

Information on the Internet

Title Illustrations
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Scientific Name Bunocephalus coracoideus
Image Use creative commons This media file is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0.
Copyright © 1995 John P. Friel
About This Page

John P. Friel
Cornell University Museum of Vertebrates, Ithaca, New York, USA

Page: Tree of Life Aspredinidae. Banjo Catfishes. Authored by John P. Friel. The TEXT of this page is licensed under the Creative Commons Attribution License - Version 3.0. Note that images and other media featured on this page are each governed by their own license, and they may or may not be available for reuse. Click on an image or a media link to access the media data window, which provides the relevant licensing information. For the general terms and conditions of ToL material reuse and redistribution, please see the Tree of Life Copyright Policies.

Citing this page:

Friel, John P. 2009. Aspredinidae. Banjo Catfishes. Version 02 March 2009 (under construction). http://tolweb.org/Aspredinidae/15208/2009.03.02 in The Tree of Life Web Project, http://tolweb.org/

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