Biology 201
Molluscan Anatomy and Diversity
Clam Photographs
Here are some of the digital
images of the clam that I have. I am providing these here for you to make the exam
go more smoothly. Study these images, but remember that there is no substitute
for the real thing. I am not suggesting that all of these shots will be on the
exam, nor am I suggesting that these are the only shots I have. Click on the
thumbnail to see a larger image.
A Key to our Four Common Clams of the Unionidae
1. Pseudocardinal teeth
present.......................................................................................................................2
Pseudocardinal teeth
absent........................................................................................................................3
2. Periostracum considerably
worn, well beyond umbo; no radial lines on the shell
.......................................................................................................................Elliptio complanata (Eastern Elliptio)
Wear on periostracum usually restricted to the umbo or its
immediate vicinity; dark radial lines on periostracum
.......................................................................................................................Lampsilis radiata (Eastern Lampmussel)
3. Nacreous layer thickened at
antero-ventral margin; anterior muscle scar distinct
.......................................................................................................................Anodonta implicata (Alewife Floater)
Nacreous layer more or less of uniform thickness; anterior
muscle scar indistinct or absent entirely
.......................................................................................................................Pyganodon cataracta (Eastern Floater)
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R.F. Lauff |