Invertebrate Identification Procedures

With the increasing amount of posts regarding identification of crayfish and mussels we have decided to post guidelines to follow for those who are requesting identification when accompanied by a picture. First and foremost, if you do not know the regulations of the state you were in regarding these taxa you should not keep/posess them, including shells of dead mussels. It is illegal in many states to possess their shells. Crayfish and mussels are not only two of the most difficult faunal groups to identifiy, but they are the most imperiled of the N.A. freshwater fauna. Widespread loss and extinction of crayfish and mussel fauna has occurred and is continuing throughout the country. Transportation and subsequent release of crayfish has resulted in loss of native fauna. All of that being said, there are methods and ethics for field observations that can contribute useful information to this group and science as a whole. There are various online keys (links are continually being complied) for several states/regions that include pictures and generalized life history.

- Mussels -
You should not disturb and remove live mussels from the substrate. Improper placement back into the substrate could cause them to become dislodged from suitable habitat and eventually result in mortality. If you find shells from a deceased specimen pictures of the exterior and interior of valve from a dead mussel are necessary. Shells should be as clean as possible and show anatomical features such as pseudocardinal and lateral teeth, ridges, knobs/pustules, ridges, beak scultpure, and umbos.

- Crayfish -
A dorsal (top) picture should show at least the carapace (head to rostrum). A ventral (bottom) picture should show a detailed picture of the gonopods (first swimmeret in males) or the annulus ventralus (receptacle in females). See this post regarding a HIGH quality image of gonopods. Other pictures such as full dorsal shots, mandibles, or claws are welcome and may be necessary. See this link on crayfish anatomy to understand terms used above.

Please include information such as state, drainage or watershed, county, and stream name where the specimen was observed. Send information to state authorities in malacology (mussels) and astacology (crayfish) with credible and accurate information when a rare species may have been encountered.

Again I will stress, if you don't know what it is and/or if it's legal, do not collect. When in doubt don't do it!

Professional malacological societies:
Freshwater Mollusk Conservation Society
American Malacological Society
Conchologists of America

Suggested literature for identification includes:

Freshwater Mussels of Tennessee (Parmalee and Bogan 1998)
Pearly Mussels of New York State (Strayer 1997)
The Pearly Mussels of Pennsylvania (Spoo 2008)
Freshwater Mussels of Alabama and the Mobile Basin in GA, MS, and TN (Williams and Bogan 2008)
Field Guide to the Freshwater Mussels of the Midwest (Cummings 1992)
Freshwater Uniocacean Clams (Burch 1975)

Online identification resources:

North Carolina
New York & New Jersey
Conn.
Hudson Bay & Lake Superior
Pacific Drainages
AR & MO - St. Francis
Mussels of the Pacific Northwest
Upper Mississippi River
Ohio River Basin

Picture galleries:
Unio Gallery