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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: Belted crayfish

Synonyms and Other Names: Orconectes harrisonii (Faxon, 1884), Big River Crayfish. Faxonius harrisonii underwent a reclassification in August 2017, changing the genus of non-cave dwelling Orconectes to Faxonius (Crandall and De Grave 2017).

Taxonomy: available through www.itis.gov

Identification: Faxonius harrisonii has a tan to a gold color body with a pattern of alternating olive-green and reddish-brown bands on the segments of the abdomen. This species received its common name from the distinctive presence of two blackish saddle marks on the anterior and posterior edges of the thorax. Unlike other crayfish within its range, the anterior saddle mark spans the junction of the head and thorax (cervical groove). The chelae (pincers) are narrow and not especially long (Williams 1954; MDC Discover Nature 2017).

Size: Total length maximum approximately 75mm (Chilton, Pers. Comm. 2018).

Native Range: Faxonius harrisonii is a narrow-range endemic found in Missouri's eastern Ozarks in both the Meramec River and Big River in St. Francis, St. Genevieve, and Washington Counties (Williams 1954; Hobbs 1974; Hobbs 1989; Pflieger 1996).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

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

Ecology: Faxonius harrisonii occurs in streams ranging in size from medium-sized creeks to large rivers. This species is often found beneath coarse rocks in stream segments with permanent flow but in the absence of strong currents (Pflieger 1996; MDC Discover Nature 2017). Faxonius harrisonii is possibly tolerant to habitat degradation, as it has been collected in large numbers in streams associated with cattle grazing, which lacked riparian vegetation and that had high flocculent algal growth (see Adams et al. 2010).

Mating typically occurs in the fall and females usually lay eggs in the spring. Females attach eggs to their swimmerets under the abdomen where the young remain attached after hatching. The female will “care” for the larvae for a period until they have completed two molts (MDC Discover Nature 2017).

Means of Introduction: Probable bait bucket introduction.

Status: Established in the upper St. Francis River, Missouri (DiStefano et al. 2015).

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: Faxonius harrisonii is a species of special concern in Missouri (Taylor et al. 1996).

References: (click for full references)

Adams, S., Schuster, G.A. & Taylor, C.A. 2010. Orconectes harrisonii. The IUCN Red List of Threatened Species 2010: e.T153942A4566958.

http://dx.doi.org/10.2305/IUCN.UK.2010-3.RLTS.T153942A4566958.en. Downloaded on 30 October 2017.

DiStefano, R. J., Imhoff, E. M., Swedberg, D. A., and T. C. Boersig III. 2015. An analysis of suspected crayfish invasions in Missouri, USA: evidence for the prevalence of short-range translocations and support for expanded survey efforts. Management of Biological Invasions. 6(4): 395-411.

Hobbs, H.H.Jr. 1974. A checklist of the North and Middle American crayfishes (Decapoda: Astacidae and Cambaridae). iSmithsonian Contributions to Zoology. 166: 1-161.
Hobbs, H. H., Jr. 1989. An illustrated checklist of the American crayfishes (Decapoda: Astacidae, Cambaridae, and Parastacidae). iSmithsonian Contributions to Zoology 480: 1- 236.

MDC Discover Nature. 2017. Missouri Department of Conservation. https://nature.mdc.mo.gov/discover-nature/field-guide/belted-crayfish-big-river-crayfish (Accessed on 6/20/2017).

Pflieger, W.L. 1996. The Crayfishes of Missouri. Missouri Department of Conservation, Jefferson City.

Taylor, C. A., Warren Jr, M. L., Fitzpatrick Jr, J. F., Hobbs III, H. H., Jezerinac, R. F., Pflieger, W. L., and H.W. Robison. 1996. Conservation status of crayfishes of the United States and Canada. Fisheries 21(4): 25-38.

Williams, A. B. 1954. Speciation and distribution of the Crayfishes of the Ozark Plateaus and Ouachita Provinces. The University of Kansas Science Bulletin 36(2): 803-918

Other Resources:
MDC Discover Nature: Belted Crayfish

Author: Daniel, W.M.

Peer Review Date: 3/20/2019

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.