Common name: Rio pearlfish
Synonyms and Other Names: White's pearlfish, Cynolebias whitei Myers 1942, Pterolebias elegans Ladiges 1958
available through www.itis.gov
Identification: Costa (1995) provided diagnostic characters and included this species in his identification keys to the genera and species of the subfamily Cynolebiatinae. Color photographs appeared in Axelrod et al. (1985) and Costa (1995). This species, formerly known by the name Cynolebias whitei, was assigned to the genus Simpsonichthys by Costa (1996), and to the genus Nematolebias by Costa (1998).
Size: 9 cm.
Native Range: Tropical America. South America in the coastal plains of Rio de Janeiro State, between Rio das Ostras and Marica, southeastern Brazil (Costa, personal communication).
Hydrologic Unit Codes (HUCs) Explained
Puerto Rico &
Interactive maps: Point Distribution Maps
This pearlfish has been listed as a nonestablished species known from open waters of California (Courtenay et al. 1986, 1991; Courtenay and Williams 1991; Williams and Jennings 1991). That listing likely based on its introduction into experimental rice plots and ponds on lands of the Butte County Mosquito Abatement District in 1973 and 1974 (e.g., Shapovalov et al. 1981; Dill and Cordone 1997), and at the Agricultural Experiment Station on the University of California Riverside (Dill and Cordone 1997).
Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Nematolebias whitei are found here.
Table last updated 11/29/2023
† Populations may not be currently present.
Means of Introduction: Intentionally stocked to assess its ability as a mosquito control agent, especially in ricefields (Dill and Cordone 1997). These studies were with the approval of the Fish and Game Commission (Dill and Cordone 1997).
Status: Failed in California (Moyle 1976). As in the case of the black pearlfish Austrolebias nigripinnis, Dill and Cordone (1997) concluded that there is no evidence that this pearlfish species was ever an inhabitant of open waters (see Remarks section).
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.
References: (click for full references)
Axelrod, H.R., W.E. Burgess, N. Pronek, and J.G. Walls. 1985. Dr. Axelrod's atlas of freshwater aquarium fishes. Tropical Fish Hobbyist Publications, Inc., Neptune City, NJ.
Costa, W.J.E.M. 1995. Pearl kililfishes - the Cynolebiatinae: systematics and biogeography of the neotropical annual fish subfamily. T.E.H. Publications, Neptune City, NJ.
Costa, W.J.E.M. 1996. Phylogenetic and biogeographic analysis of the Neotropical annual fish genus Simpsonichthys (Cyprinodontiformes: Rivulidae). Journal of Comparative Biology 1:129-140
Costa, W.J.E.M. 1998. Phylogeny and classification of Rivulidae revisited: origin and evolution of annualism and miniaturization in rivulid fishes (Cyprinodontiformes: Aplocheiloidei). Journal of Comparative Biology 3:33-92.
Courtenay, W.R., Jr., D.A. Hensley, J.N. Taylor, and J.A. McCann. 1986. Distribution of exotici fishes in North America. 675-698 in Hocutt, C.H., and E.O. Wiley, eds. 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. 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.
Dill, W.A., and A.J. Cordone. 1997. History and status of introduced fishes in California, 1871-1996. California Department of Fish and Game Fish Bulletin, volume 178.
Moyle, P. B. 1976. Inland fishes of California. University of California Press, Berkeley, CA.
Shapovalov, L., A.J. Cordone, and W.A. Dill. 1981. A list of freshwater and anadromous fishes of California. California Fish ad Game 67(1):4-38.
Williams, J.D. and D.P. Jennings. 1991. Computerized data base for exotic fishes: the western United States. California Fish and Game 77(2):86-93.
Leo Nico, and Matt Neilson
Revision Date: 4/30/2018
Peer Review Date: 3/1/2012
Leo Nico, and Matt Neilson, 2023, Nematolebias whitei (Myers, 1942): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=882, Revision Date: 4/30/2018, Peer Review Date: 3/1/2012, Access Date: 11/29/2023
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.