SkaTES, RAYS and FISH

 

EOCENE SAWFISH
Pristis sp. (Linck)

Age  Eocene - Occurrence  Uncommon

The sawfish is not a shark but a skate. In Monmouth County, NJ, Pristis is known only from its rostral “teeth” or spines, little is know about the oral teeth. The "saw" itself is an elongated rostral projection from the cranium, bearing on each side a series of large tooth-like structures. The rostral teeth are embedded in deep sockets of hardened cartilage. These teeth are flattened with a slightly striate base and can reach lengths of over 3 inches. The anterior edge forms what can best be described as a dull cutting edge, while the posterior edge is concave. Pristis is known from the lower Eocene to the present, but is strictly found as an Eocene fossil in NJ.
Note: “Eocene Sawfish” is not an accepted common name outside of New Jersey.

Two examples of Pristis sawfish rostral "teeth" or spines.
 The spine on the left is 3/4's of an inch, the spine on the left checks in at 2 inches.

Modern sawfish often feed by attacking schools of fish, slashing sideways through
 the school and impaling or stunning their prey on their rostral teeth.

Monmouth County, NJ

A distinguishing characteristic of Pristis is the channel or grove on the
 posterior edge.
 

The rostral spines grow continuously, and growth rings may be visible
on spines that are not too stream worn.  
 

A head-on view (upper left), the grove or channel is clearly visible.
A large fragment (right). I'm guessing that if complete, this spine would
easily have exceeded 2 inches.
 

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