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Hammerhead shark: labial (left) and lingual view of a relatively large
hammerhead shark tooth (15mm wide, 12.5mm heigh). Hammerhead teeth are very
similar in shape to C. brachyurus. To tell them apart, note the lack
of serrations (some large teeth have very weak serrations on the shoulder),
the sharp angle between the distal shoulder and the straight distal cutting
edge of the crown, which often creates a
distinct notch, and the broad prominent nutrient groove. In this particular specimen, the distal shoulder is rather straight. In many other teeth it has a more curved, blade-like appearance. |
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For comparison, the picture on the left shows a C. brachyurus or
Copper shark tooth with
a very similar overall shape. Note that the distal shoulder and crown meet in
a smooth curve. Some C. brachyurus teeth have a notch where the coarser
serrations on the shoulder meet the finer serrations on the crown, but they
do not have the sharp angle seen in hammerheads. Also note the lack of a
prominent nutrient groove.
A very worn Copper shark tooth may have lost its serrations, and look very
similar to a hammerhead. It is easy to tell wear and tear from a true smooth
cutting edge by comparing teeth through a magnifying glass. The cutting
edge of a hammerhead is smooth, but very sharp. A worn copper shark
tooth would be smooth, but the edge would also look rounded, and not sharp.
This is another reason to separate worn and broken teeth from your nice
finds (you don't have to throw them away, just keep them separate...).