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.

Elaphoidella bidens bidens
(a copepod)

Copyright Info
Elaphoidella bidens bidens (Schmeil, 1894)

Common name: a copepod

Taxonomy: available through www.itis.govITIS logo

Size: Less than 1 mm

Native Range: The genus has a worldwide distribution. However, Bruno et al. (2000) believe it may be introduced to North America from Eurasia as a large majority of records come from disturbed habitats.

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

Nonindigenous Occurrences:

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 Elaphoidella bidens bidens are found here.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
DC200520051Mid Atlantic Region
FL200520051South Atlantic-Gulf Region
GA200520051South Atlantic-Gulf Region
ME200520051New England Region
MD200520051Mid Atlantic Region
SC200520051South Atlantic-Gulf Region

Table last updated 9/16/2021

† Populations may not be currently present.

* HUCs are not listed for states where the observation(s) cannot be approximated to a HUC (e.g. state centroids or Canadian provinces).

Ecology: This species inhabits freshwater lakes, streams, reservoirs, and marshes; can tolerate eutrophic waters (Hudson and Lesko, 2003).

Means of Introduction: Unknown, but because it has also been found in the Great Lakes, ballast water may have been how it was introduced initially.

Status: Unknown.

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: Males are rarely encountered, and the most common mode of reproduction is parthenogenesis (Hudson and Lesko, 2003). This characteristic makes it different from all of its other North American congeners (Bruno et al., 2000). Adults are capable surviving complete desiccation for months; the nauplii of this species have been found in mud taken from the feet of shore birds (Hudson and Lesko, 2003).

References: (click for full references)

Bruno, M.C., J.W. Reid, and S.A. Perry. 2000. New records of copepods from Everglades National Park (Florida): description of two new species of Elaphoidella (Harpacticoida, Canthocamptidae), and supplementary description of Diacyclops nearcticus Kiefer (Cyclopoida, Cyclopidae). Crustaceana 73:1171-1204.

Hudson, P.L., and L.T. Lesko. 2003. Free-living and Parasitic Copepods of the Laurentian Great Lakes: Keys and Details on Individual Species. Ann Arbor, MI: Great Lakes Science Center Home Page. http://www.glsc.usgs.gov/greatlakescopepods/

McLaughlin, P.L. and 38 others. 2005. Common and scientific names of aquatic invertebrates from the United States and Canada: Crustaceans. American Fisheries Society Special Publication 31, Bethesda, Maryland.

Author: Benson, A.J.

Revision Date: 3/1/2013

Citation Information:
Benson, A.J., 2021, Elaphoidella bidens bidens (Schmeil, 1894): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=2772, Revision Date: 3/1/2013, Access Date: 9/16/2021

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.


The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Citation information: U.S. Geological Survey. [2021]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [9/16/2021].

Contact us if you are using data from this site for a publication to make sure the data are being used appropriately and for potential co-authorship if warranted. For queries involving fish, please contact Matthew Neilson. For queries involving invertebrates, contact Amy Benson.