What are hinge teeth?
Q: What are hinge teeth?
A: Hinge teeth are part of the inner surface of the shell of a bivalve mollusc.
Q: What are bivalves?
A: Bivalves are shellfish that have two valves (parts of the shell) joined together by a strong and flexible ligament on the hinge line at the dorsal (top) edge of the shell.
Q: Why do bivalves need hinge teeth?
A: In life, the shell needs to be able to open slightly to allow the foot and siphons to protrude, and then close again, without the valves moving out of alignment with one another. To make this possible, the two valves usually have hinge teeth (the "dentition").
Q: Where are hinge teeth located?
A: Like the ligament, the hinge teeth are along the hinge line of the shell.
Q: Are the two valves of a bivalve perfectly symmetrical with each other along the hinge line?
A: In most families, the two valves of the shell are almost perfectly symmetrical with one another along the hinge line, though the placement and shape of the teeth may differ slightly in the left valve and right valve so the two valves fit together properly.
Q: Why is examining the arrangement of the hinge teeth important?
A: Examining the arrangement of the hinge teeth in a bivalve shell is often essential for identification and classification because each group of bivalves tends to have distinctive hinge teeth.
Q: What is the function of the strong and flexible ligament that joins the two valves of a bivalve shell?
A: The strong and flexible ligament on the hinge line of the shell allows the shell to open slightly to allow the foot and siphons to protrude, and then close again, without the valves moving out of alignment with one another.
