THE SHARKS

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Hammerhead
Sphyrna laevissima (Cope)
Sphyrna laevissima (Cope) is synonymized with S. zygaena (Linnaeus)

Age - Miocene  Commonality - Uncommon

The hammerhead ( Sphyrna laevissima ) tooth is an unusual find in New Jersey. The teeth of this well known shark range in size from ¼ of an inch up to an inch, with the average being a little less than ½ inch. The cutting edge is smooth with a distinctive notch on the distal side often referred to as the “hammerhead notch”. The root posses a strong nutrient grove.  I've found the teeth of Sphyrna laevissima tend to be on the smaller side in NJ and most will slip thru the standard 1/4 inch screening. Most of my examples have been found using a finer mesh screen.

 


 


Recent studies suggest that the placement of  eyes on this curious creature give the hammerhead outstanding binocular vision and an ability to see through 360 degrees.
 


 

Labial and lingual views of the same tooth
Monmouth County, NJ
This is my only relatively complete NJ specimen.


 


Strongly notched distal margin and lack of serrations
are two characteristics of Sphyrna laevissima.


 

A pair of hammerheads collected from Calvert Cliffs, MD.
Sphyrna laevissima was first described from the Calvert Cliffs
area.

 


 

Note the distinctive “hammerhead notch” and lack of serrations on the crown.
The notch on the root is formed by the strong nutrient grove
Calvert Cliffs, MD
 

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