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.

Crangonyx pseudogracilis
Crangonyx pseudogracilis
(northern river crangonyctid)
Native Transplant

Copyright Info
Crangonyx pseudogracilis Bousfield, 1958

Common name: northern river crangonyctid

Taxonomy: available through www.itis.govITIS logo

Native Range: It is widely distributed in east-central United States and southern Canada, occurring largely west of the Appalachians, extending approximately from the Great Lakes region, south and southwest to Louisiana and Texas (Zhang and Holsinger, 2003 cited in Encyclopedia of Life).

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 Crangonyx pseudogracilis are found here.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
CA200220031Central Coastal
OR200220021Lower Willamette
WA200220021Lower Columbia-Clatskanie

Table last updated 2/27/2023

† Populations may not be currently present.

References: (click for full references)

Encyclopedia of Life (http://eol.org/pages/344045/details)

Revision Date: 8/26/2015

Citation Information:
U.S. Geological Survey, 2023, Crangonyx pseudogracilis Bousfield, 1958: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=2387, Revision Date: 8/26/2015, Access Date: 3/31/2023

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.


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. [2023]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [3/31/2023].

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