Ray Tooth Id Needed

[John Hamilton]

Found this ray tooth in Lee Creek matrix. Could it be a pathologic female dasyatis?

Edited August 26, 2013 by John Hamilton

[Al Dente]

I think it is a male Dasyatis.

[John Hamilton]

I think it is a male Dasyatis.

Al,

What do you see that identifies this as a male tooth? I thought male teeth had high cusp and this tooth has a compressed globular crown with a cusp.

Edited August 27, 2013 by John Hamilton

[Al Dente]

Male Dasyatis will form pointed teeth during their breeding season and when the breeding season is over they will form teeth that are identicle to female teeth. There are intermediate teeth that are formed before the full breeding dentition is in place. I think your tooth might be this intermediate phase or it could be a worn or deformed breeding male tooth. Here is a comparison. The tooth on the left is female or non breeding male, the tooth on the right is breeding male and I've added your tooth for comparison.

A paper that demonstrates the change in Dasyatis dentition with the seasons is:

Seasonal Dynamics of Dental Sexual Dimorphism in the Atlantic Stingray Dasyatis sabina, Kajuira and Tricas, 1996, The Journal of Experimental Biology 199, 2297-2306.

[John Hamilton]

Male Dasyatis will form pointed teeth during their breeding season and when the breeding season is over they will form teeth that are identicle to female teeth. There are intermediate teeth that are formed before the full breeding dentition is in place. I think your tooth might be this intermediate phase or it could be a worn or deformed breeding male tooth. Here is a comparison. The tooth on the left is female or non breeding male, the tooth on the right is breeding male and I've added your tooth for comparison.

dasycomparison.jpg

A paper that demonstrates the change in Dasyatis dentition with the seasons is:

Seasonal Dynamics of Dental Sexual Dimorphism in the Atlantic Stingray Dasyatis sabina, Kajuira and Tricas, 1996, The Journal of Experimental Biology 199, 2297-2306.

After reading this paper I concur with your identification. Thanks for the help.

[MarcoSr]

Seasonal Dynamics of Dental Sexual Dimorphism in the Atlantic Stingray Dasyatis sabina, Kajuira and Tricas, 1996, The Journal of Experimental Biology 199, 2297-2306.

Thank you for the reference. I didn't know that the pointed male teeth were seasonal. I have a lot of what I thought were female teeth that might really be male teeth. Doing a little research on the web there are several on going studies looking at other rays and some sharks to see if the males also have breeding seasonal teeth. Now I wonder if fossil Raja male teeth or Rhinobatos male teeth with the pointed crowns were only seasonal. Have you come across any articles about them?

Marco Sr.