Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Clickable Guide
Moths Butterflies Flies Caterpillars Flies Dragonflies Flies Mantids Cockroaches Bees and Wasps Walkingsticks Earwigs Ants Termites Hoppers and Kin Hoppers and Kin Beetles True Bugs Fleas Grasshoppers and Kin Ticks Spiders Scorpions Centipedes Millipedes

Sponsor
The Coleopterists Society supports BugGuide.

Calendar
Upcoming Events

Discussion, insects and people from the 2018 BugGuide Gathering in Virginia, July 27-29

Photos of insects and people from the 2015 gathering in Wisconsin, July 10-12

Photos of insects and people from the 2014 gathering in Virginia, June 4-7.

Photos of insects and people from the 2013 gathering in Arizona, July 25-28

Photos of insects and people from the 2012 gathering in Alabama

Photos of insects and people from the 2011 gathering in Iowa

Photos from the 2010 Workshop in Grinnell, Iowa

Photos from the 2009 gathering in Washington

TaxonomyBrowse
Info
ImagesLinksBooksData

Species Orconectes immunis - Calico Crayfish

crawfish - Orconectes immunis defensive crayfish - Orconectes immunis
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Crustacea (Crustaceans)
Class Malacostraca (Malacostracans)
Superorder Eucarida (Eucarida (Crabs, Crayfish, Shrimp, etc.))
Order Decapoda (Crabs, Crayfishes, Lobsters, Prawns, and Shrimp)
Infraorder Astacidea (Crayfishes and Lobsters)
Superfamily Astacoidea (Crayfishes)
Family Cambaridae
Genus Orconectes
No Taxon (Subgenus Trisellescens)
Species immunis (Calico Crayfish)
Other Common Names
Papershell Crayfish
Identification
Rostrum acuminate, acarinate and with converging margins lacking marginal spines or shoulders; cervical spines present; areola narrow with 2-3 punctations in narrowest part; male with hooks on ischia of 3rd pereiopods; male first pleopod terminating in 2 subparallel elements less than 25% length of pleopod, curved throughout length but distal 1/3 more pronounced so that apices of both elements directed at about 90 degrees to main axis of pleopod (Page, 1985). [LENGTH: to 50 TCL; to 95 TL] [WIDTH: to 25] (MFG)

O. immunis have characteristically long, slender chelae with a very splotchy coloration, but these features are a bit difficult to use as diagnostic characters without a few reference specimens. The easiest way to distinguish between O. immunis and O. virilis is the notch near the base of the dactyl, or 'thumb' of the cheliped--O. immunis has it, O. virilis does not. (MFG)
Range
O. immunis has a widespread North American native range from southern Quebec, Canada and New England westward across the upper Midwest to Wyoming and eastern Colorado and the Dakotas and south to extreme northwestern Tennessee (Hobbs, 1989; Pflieger, 1996). Montana's eastern plains populations are the furthest reported western extent this species ranges.
Habitat
Lentic environments; Ponds, roadside ditches, and sluggish streams.
Food
This species is an omnivorous detritivore and a scavenger, feeding by shredding large pieces of organic materials and shredding them up.