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.

Faxonius hylas
Faxonius hylas
(Woodland crayfish)
Native Transplant

Copyright Info
Faxonius hylas (Faxon, 1890)

Common name: Woodland crayfish

Synonyms and Other Names: Orconectes hylas (Faxon, 1890). Faxonius hylas 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.govITIS logo

Identification: The woodland crayfish is about 1-2.5 inches long, with a reddish tan or dark brown body covered in black specks and blotches. They have a narrow, crescent shaped band that extends across the rear margin of the carapace onto the first abdominal segment. The main distinguishing characteristic of this crayfish are it's blotches (Missouri Department of Conservation 2016).

Size: 1 - 2.5 inches (Missouri Department of Conservation 2016)

Native Range: Endemic to the Black River, and headwaters of the Meramec River and Big River drainages in Missouri (DiStefano et al. 2002).

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 Faxonius hylas are found here.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
MO198420081Upper St. Francis

Table last updated 8/17/2022

† Populations may not be currently present.

Ecology: Woodland crayfish prefer shallow pools and streams with substrate dominated by gravel, pebble, cobble and exposed bedrock (Westhoff and Rabeni 2013).

Means of Introduction: Possibly introduced in the St. Francis River drainage through bait bucket releases (DiStefano 2008).

Status: Established in the St. Francis drainage in Missouri (DiStephano et al. 2002).

Impact of Introduction: Two native crayfish species, O. peruncus and O. quadruncus, were eliminated from the areas in the St. Francis where O. hylas had invaded (Riggert et al. 2009; DiStephano et al. 2002). DiStephano et al. (2002) examined the native and introduced populations of O. hylas to determine the potential mechanism of exclusion. Hatchling O. hylas were found to grow faster than the native species, and fecundity was higher.


References: (click for full references)

Crandall, K.A. and S. De Grave. 2017. An updated classification of the freshwater crayfishes (Decapoda: Astacidea) of the world, with a complete species list. Journal of Crustacean Biology 37(5):615-653. https://doi.org/10.1093/jcbiol/rux070.

DiStefano, R.J. 2008. Conservation of imperiled crayfish-Orconectes (Procericambarus) peruncus (Creaser, 1931)(Decapoda: Cambaridae). Journal of Crustacean Biology 28(1): 189-192.

DiStefano, R. J., J. Young, and D.B. Noltie. 2002. A study of the life history of Orconectes hylas with comparisons to Orconectes peruncus and Orconectes quadruncus in Ozark streams, Missouri, USA. Freshwater Crayfish 13: 439-456.

Missouri Deparment of Conservation. 2016. Orconectes hylas. Available at: https://nature.mdc.mo.gov/discover-nature/field-guide/woodland-crayfish

Riggert, C. M., R.J. Distefano, and D.B. Noltie. 1999. Distributions and selected aspects of the life histories and habitat associations of the crayfishes Orconectes peruncus (Creaser, 1931) and O. quadruncus (Creaser, 1933) in Missouri. The American Midland Naturalist 142(2): 348-362.

Westhoff, J.T. and C.F. Rabeni. 2013. Resource selection and space use of a native and an invasive crayfish: evidence for competitive exclusion? Freshwater Science 32(4): 1383-1397.


Author: Hosabettu, M. and W.M. Daniel

Revision Date: 1/9/2018

Citation Information:
Hosabettu, M. and W.M. Daniel, 2022, Faxonius hylas (Faxon, 1890): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=2342, Revision Date: 1/9/2018, Access Date: 8/17/2022

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. [2022]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [8/17/2022].

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 general information and questions about the database, contact Wesley Daniel. For problems and technical issues, contact Matthew Neilson.