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The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

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Common name: ripsaw catfish

Synonyms and Other Names: Pseudodoras niger, black doradid, black shielded catfish, blue dolphin, dolphin catfish, fork-snout catfish, terushuki, cuiu-cuiu, sierra negra

Taxonomy: available through www.itis.gov

Identification: Higuchi (1992) gave diagnostic characters of the genus. Somewhat dated keys to the genera and species of Doradidae, including O. niger, were provided by Eigenmann (1925) and Schultz (1944), with more recent information in Sabaj and Ferraris (2003). Distinguishing characteristics, color photographs of live fish, and a key to doradid genera were given by Burgess (1989).

Size: 120-cm fork length and 20 kg.

Native Range: South America. Very common in the Guiana region, São Francisco and Essequibo River basins, and entire Amazon basin of South America from Peru to the Brazilian state of Para (Higuchi 1992). Possibly in the Orinoco River basin.

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Ecology: Oxydoras niger is primarily a benthic omnivore, consuming aquatic invertebrates, plant material, and detritus (Mérona et al. 2001).

Means of Introduction: This species was probably an aquarium release, as many species of Doradidae are popular in the aquarium trade.

Status: Failed in Florida.

Impact of Introduction: The impacts of this species are currently unknown, as no studies have been done to determine how it has affected ecosystems in the invaded range. The absence of data does not equate to lack of effects. It does, however, mean that research is required to evaluate effects before conclusions can be made.

Remarks: There is some confusion in the literature concerning the Florida record and the positive identification of the Florida specimen. The listing for Florida of Oxydoras sp. (Courtenay et al. 1986) and Florida listings of Oxydoras niger or Pseudodoras niger (Courtenay et al. 1984; 1991; Courtenay and Stauffer 1990; Robins et al. 1991b; Courtenay and Williams 1992) most likely represent the same record. Pseudodoras niger is a name sometimes used for Oxydoras knerii, a species distinct from O. niger (C. Ferraris, personal communication). The whereabouts of the Florida specimen is not known.

References: (click for full references)

Burgess, W. E. 1989. An atlas of freshwater and marine catfishes: a preliminary survey of the Siluriformes. Tropical Fish Hobbyist Publications, Inc., Neptune City, NJ.

Courtenay, W. R., Jr., and J. R. Stauffer, Jr.. 1990. The introduced fish problem and the aquarium fish industry. Journal of the World Aquaculture Society 21(3):145-159.

Burgess, W. E. 1989. An atlas of freshwater and marine catfishes: a preliminary survey of the Siluriformes. Tropical Fish Hobbyist Publications, Inc., Neptune City, NJ.

Courtenay, W.R., Jr. and J.D. Williams. 1992. Dispersal of exotic species from aquaculture sources, with emphasis on freshwater fishes Pages 49-81 in A. Rosenfield and R. Mann, eds. Dispersal Of living organisms into aquatic ecosystems. Maryland Sea Grant College Park, MD.

Courtenay, W. R., Jr., D. A. Hensley, J. N. Taylor, and J. A. McCann. 1984. Distribution of exotic fishes in the continental United States. Pages 41-77 in W. R. Courtenay, Jr., and J. R. Stauffer, Jr., editors. Distribution, biology and management of exotic fishes. Johns Hopkins University Press, Baltimore, MD.

Courtenay, W. R., Jr., D. A. Hensley, J. N. Taylor, and J. A. McCann. 1986. Distribution of exotic fishes in North America. Pages 675-698 in C. H. Hocutt, and E. O. Wiley, editors. The zoogeography of North American freshwater fishes. John Wiley and Sons, New York, NY.

Courtenay, W. R., Jr., D. P. Jennings, and J. D. Williams. 1991. Appendix 2: exotic fishes. Pages 97-107 in Robins, C. R., R. M. Bailey, C. E. Bond, J. R. Brooker, E. A. Lachner, R. N. Lea, and W. B. Scott. Common and scientific names of fishes from the United States and Canada, 5th edition. American Fisheries Society Special Publication 20. American Fisheries Society, Bethesda, MD.

Eigenmann, C.H. 1925. A review of the Doradidae, a family of South American Nematognathi, or catfishes. Transactions of the American Philosophical Society 22:280-365.

Higuchi, H. 1992. A phylogeny of South American thorny catfishes (Osteichthyes; Siluriformes; Doradidae). PhD dissertation, Harvard University, Cambridge, MA.

Mérona, B. de, G.M. dos Santos, and R.G de Almeida. 2001. Short-term effects of Tucurui Dam (Amazonia, Brazil) on the trophic organization of fish communities. Environmental Biology of Fishes 60:375-392.

Robins, C. R., R. M. Bailey, C. E. Bond, J. R. Brooker, E. A. Lachner, R. N. Lea, and W. B. Scott. 1991. World fishes important to North Americans exclusive of species from the continental waters of the United States and Canada. American Fisheries Society Special Publication 21. American Fisheries Society, Bethesda, MD.

Sabaj, M.H. and C.J. Ferraris Jr., 2003. Doradidae (Thorny catfishes). 456-469 in R.E. Reis, S.O. Kullander and C.J. Ferraris, Jr., eds. Checklist of the freshwater fishes of South and Central America. Porto Alegre: EDIPUCRS, Brasil.

Schultz, L. P. 1944. The catfishes of Venezuela, with descriptions of thirty-eight new forms. Proceedings of the U.S. National Museum 94(3172):173-338.

Other Resources:
US Fish and Wildlife Service Ecological Risk Screening Summary for Oxydoras niger

Author: Leo Nico, Matt Neilson, and Bill Loftus

Peer Review Date: 10/3/2012

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.