SkaTES, RAYS and FISH

 

GUITARFISH
Rhinobatos casieri (Herman)

Age  Cretaceous - Occurrence  Scarce
 

The teeth of Rhinobatos casieri, also known as the Guitarfish, are small, averaging a little less than 2mm wide. Besides their size, the teeth of this skate have a few characteristics that make them difficult to confuse with any other species found in New Jersey. To me, what makes this tooth stand out is the root. The root is large with a very deep nutrient grove and when viewed from the side, angles towards the lingual side of the tooth. The crown is smooth with a transverse ridge and has a bizarre looking central uvula. There are also smaller lateral uvula to either side of the central uvula. On the labial side of the crown, two to three small depressions may be present.      

The teeth of Rhinobatos casieri are small, averaging under 2mm
at the widest point. A fine mesh screen is a definite must for these little
guys.
Left - Side view   Right - Lingual view
Monmouth County,  NJ
 

In-vivo wear on the crown can completely obscure the transverse ridge.
The tooth on the left shows almost no wear. The tooth on right shows
significant wear. All rays and skates seem prone to these wear patterns.

Side view of Rhinobatos casieri, the root angles towards the lingual
side of the tooth.

Looking at a guitarfish tooth from above. (A) the central uvula,
(B) lateral uvula.
Note: The root was digitally removed in this image.
 

The roots are unique looking, but very prone to breakage.
Note the depressions on the labial side of the tooth, two to three are
usually present.
 

Using a US dime for scale shows just how small these teeth are.
 

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