PLEISTOCENE FOSSILS 123 



Sphaeriidae: beaks almost in the center of the hinge, their sculpture 

 like that of the remainder of the shell; cardinal teeth almost directly 

 under the beaks; two groups of lateral teeth, one at each end of the 

 hinge; adults less than one inch long. 



Unionidae: Beaks near one end of the hinge, their sculpture different 

 from that of the remainder of the shell; one group of teeth (called 

 pseudocardinals, but usually referred to as cardinals) under the beaks 

 and another (laterals) parallel to the hinge and behind the beaks; one 

 or both of these groups of teeth may be lacking; adults more than one 

 inch long. 



1. 



a) 





b) 



2. 



a) 





b) 



3. 



a ) 





b) 



4. 



a) 





b) 



5. 



a) 





b) 



6. 



a) 





b) 



7. 



a) 





b) 



8. 



a) 





b) 



9. 



a) 





b) 



Key to the Commoner Pleistocene Unionidae of Ohio 

 (see p. 4 for use of keys) 



Hinge without teeth Anodonta 



Hinge with one or more teeth 2 



Length 1. 5 times or more the height 3 



Length and height almost equal 7 



Teeth consisting of indistinct swellings Strophitus 



Teeth distinct and prominent 4 



Shell with flutings at one end Lasmigona 



Shell without flutings 5 



Shell much thicker at one end Elliptio 



Shell not noticeably thicker at one end 6 



Shell convex, almost cylindrical Ligumia 



Shell compressed Lampsilis 



Shell winged 8 



Shell not winged 9 



Teeth under beaks poorly developed; shell solid Proptera 



Teeth under beaks well developed; shell thin and fragile Leptodea 



Shell almost round in outline; beaks low; teeth large and 



solid Obovaria 



Shell oval in outline; beaks swollen; teeth small Lampsilis 



