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For some reason all of the crayfish I've been researching online doesn't match what crayfish I caught last spring in Fox River- in Illinois... I've been amazed by those two as they turned BLUE with color of the gravel being black/blue- until up to 2 months ago, they started to color up and still is pale color- they've been amazing specimens as I caught them when they were babies being able to hold them on my hand without being pinched however recently they've ripped each others legs off and I wanted to Identify what they are- from my research now I know both ARE males but they're in a 20g. long tank with MANY hiding spots, shares their home with firebelly toads(they never bothered the frogs) other crays from a different river *id is impossible at this point as they're still babies* and lined minnows along with a tadpole madtom. I removed them and put both of them in an observation tank to see if they're okay as I never bothered to keep crays that long as they were just fish food to me until those two came along and I think they're cool to look at now
instead of being a fish food.

First Male- this one has the dots randomly over his body







Second Male- no dots but has the bigger lone claw as the the 1st male still has both of his but littler





they're from the fox river in Illinois- please help this clueless newbie out

Interesting color. No idea about species though.

http://iz.carnegiemnh.org/crayfish/coun ... linois.htm

Based on your last photograph that shows a decent view of the carapace, rostrum, and cheliped (claw), I'd put my money on Orconectes immunis. It seems to be the best fit from the diagrams for the species in your state.

Of course, I'd still need to see a form I male under the microscope for a 100% positive ID because most of the other morphological characteristics can be somewhat variable in the population and the diagrams never seem to be perfect.

Here are the diagrams for this species from the illustrated checklist.

I would vote no. All immunis have a diamond patter down the back of their tails. Thats why they are also called diamond back crayfish.

The one with the white belly looksl like its about to molt.

is it possible I discovered new species?

KaiOnca wrote: is it possible I discovered new species?

It is always possible, but not likely.

Color variations are the most variable traits and are never used for a positive identification of a species, although they can still be very useful if you know the typical color pattern dominant in your location.

O. immunis is one of the most common species, as it exists in over half of the US states and 3 provinces of Canada.

If you look at the diagrams above, the 4 diagrams in the middle are the real key to identifying the species. Someone would need to see these reproductive structures of a form I male in order to really pin down the species.

After a little more investigation, I don't think this is Orconectes at all. Instead I think you have the "Prarie Crayfish", Procambarus gracilis. I should have looked further than just the Orconectes genus. . . .

It kind of looks like a digger crayfish species. The abdomen is rather small compared to the body