Sexing Crays

[bettagurl]

I have a 'common' cray.. not sure of their name, but it's the same kind you can find all over in creeks, ponds, in feeder tanks(lol) and ect..
I wanted to know if there is a good way to tell male from female?

If it helps, I'll try to get a pic later..

[vampie]

I believe when viewed from underneath, males have additional appendages between their legs, while females don't.

[THE V]

http://www.crayfishworld.com/sexy.htm

Depending on the species there are different structures on the underside.

[bettagurl]

Thanks..

Nice link, I think I have a female.

[blazingazn]

http://www.crayfishworld.com/sexy.htm

Depending on the species there are different structures on the underside.

if i remember my invert class correctly, this statement is wrong. all macrurans (long bodied crustaceans such as lobsters, crayfishes, and shrimp) all have basically the same structures and the gonopods are in the same relative positions. males have a gonopore opening on the coxa of the T8's ("shoulders" on the last pair of walking legs). these are tiny and are hard to see. males also have a modified first swimmeret (the legs under the abdomen) it is longer and thicker than the rest and is used to deliver the spermatophore to the female. females, on the other hand, have their gonopore openings on the coxa of the T6's ("shoulders" on the second pair of walking legs) these openings are larger and easier to see.

in that link, u can see the male is on the left while the female is on the right side. the top left shows the male openings on the shoulder of the last pair of walking legs. and the two pix below that show a thicker and longer swimmeret that i was talking about. on the top right, it shows the female openings on the shoulder of the second pair of walking legs. compared to the males, the female openings are clearer. i hope i am clear on this.