Hinge Teeth
Alasmidonta heterodon unique with 2 lateral teeth in the right valve, 1 in the left |
Elliptio complanata sharp, prominent laterals and large pseudocardinals | The hinge "teeth" are small structures of irregular shape and size that hold the two halves of the shell together. |
Alasmidonta undulata laterals may be vestigial, with heavy, triangular pseudocardinals |
Margaritifera margaritifera large, conspicuous, triangular pseudocardinals; laterals absent | The principal teeth are the pseudocardinals and the laterals; a few species have a third type, the interdental, that lies between the two. |
Lampsilis radiata laterals may be weak but clearly defined; interdentals present |
Strophitus undulatus some species have all teeth poorly defined or absent | Each type of tooth may be absent or vestigial, and their presence, absence and combination can be definitive for species identification. |