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SKATES, RAYS and FISH

 

EXTINCT SAWFISH
Ptychotrygon vermiculata (Cappetta )
Ptychotrygon cuspidata (Cappetta & Case)

Age  Cretaceous - Occurrence  Common

( Common terms for ray teeth )

Case and Cappetta¹ report two species of Ptychotrygon as being found in New Jersey, P. vermiculata and P. cuspidata. These teeth are small, averaging between 2 – 5 mm in width and rather distinct. The crowns are laterally expanded with a transverse crest or cutting edge and a  strong labial visor. The roots have a strong nutrient grove with a central foramen. There is a lateral foramen on the lingual face of each lobe. When viewed from the bottom, the roots are triangular in shape. The difference between the two species is most apparent in the crown.  P. cuspidata has a higher crown and lacks the extra transverse ridges of P. vermiculata. P. cuspidata has a more ornate crown that is best described as a series of bumps and wrinkles. Originally no rostral spines had been attributed to Ptychotrygon, this has changed in the past several years. (see Plate_2).

 


 

Ptychotrygon sp.

The teeth of the extinct sawfish are small, averaging between
2 to 5 mm across.
Monmouth County, NJ
 


 

Plate 2
Ptychotrygon rostral spine

 


 


Ptychotrygon rostral spine


 

The roots of Ptychotrygon have a lateral a lateral foramen on the lingual face
of each lobe (left) and a central foramen in the nutrient grove (right).
There is a a depression on the lingual face of the crown (blue arrow).

 


 

The triangular root lobe and strong nutrient grove.
Ruler in mm.


 

Ptychotrygon vermiculata

Ptychotrygon vermiculata - lingual view
Low crown
 

 


 

Ptychotrygon cuspidata

Ptychotrygon cuspidata -  lingual view
High Crown
 

 


 

Ptychotrygon cuspidata - occlusal view
The ornamentation on the labial visor (bottom of picture)
 


 

A random sample under a microscope.
A good portion of these teeth have some sort of root damage.
 

Author’s note: I’ve examined a significant number of specimens from New Jersey and found that while a number of teeth where easy to attribute to either P. vermiculata or P. cuspidata the vast majority seemed to fall into a no mans land between the two species. I could not assign these teeth to either species with any degree of certainty.

 



1.  Case, G., and H. Cappetta, 2004. Additions to the elasmobranch fauna from the Late Cretaceous of New Jersey (Lower Navesink Formation, Early Maastrichtian). Palaeovertebrata 33

 

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