Re: NANFA-- Crayfish ID

Dave Neely (rheopresbe_at_hotmail.com)
Sun, 02 Jan 2000 10:21:44 CST

Dave,

>One of the crayfish is completely different than any I have
>collected or kept. It was collected from Catoctin Creek in Frederick >Co
>MD(as are all the others). The crayfish is about 4" long and a
>deep,uniform blue color. The large claws are more slender and sharper >the
>other crayfish I have collected and kept.

Keith Crandall's site, which Ron posted a link to, is really good. The
section on WV crayfishes is a good place to start. However, accurate
identification of crayfishes is pretty dependent on male naughty bits, and
then only of Form I males. Pictures are nice, but color can be a deceiving
character.

If you flip your crayfish over, and look at the legs under the tail, they
are easy to sex - the pair of legs nearest the abdomen are modified into an
intromittent organ in males- they lie close to the body and project towards
the head. The terminal end of it is variously modified, with from one to
several projections, and may be bent at various angles, or even hook-like.
In females they look like the other legs under the tail.

Most of the crayfish in the MD area are in the Form I stage during late Fall
and early winter- right now. When I get back to Alabama (a couple of days
from now), I can send you a photocopy of a key to MD/WV crayfishes. You
should be able to ID it relatively easily with just a magnifying glass.

Cheers,
Dave

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