?? shark tooth

[drbush]

Hi friends, I wish you all good health, can you help me with this?  I went to Khrase city, Rus formation, Eocene, to the east of Riyadh and found many shark teeth. It was a surface find.

can you kindly help me identify the species. It is 10mm from root lobe to crown tip , root is 10mm. 

 could it be Carcharhinus underwoodi or other sp.

[Tidgy's Dad]

Nice tooth, but looks more like Galeocerdo to me. 

Let's see what the shark tooth specialists say. 

[caldigger]

Are both sets of pictures of your same specimen or are you doing a comparison post? 

[Miocene_Mason]

It looks like a Triakid shark tooth to me. My first guess would be Galeorhinus ypresiensis, which is about this size, has those prominent serrations, and is from the time period.

[drbush]

the photo for the same tooth

[drbush]

Her I am comparing between 3 sp. this might help to reach to clear identification of the species. 

[Natalie81]

I also would lean to Galeorhinus 

[Al Dente]

These types of Eocene teeth can be difficult because different publications will have completely different IDs for similar teeth. It is not likely Galeorhinus because Galeorhinus will have an enamel apron hanging over the root that this tooth lacks. It is most likely one of the Physogaleus species or Galeocerdo species. There are several Galeocerdo species named from the Eocene including G. eaglesomei, G. latidens, G. alabamensis, G. clarkensis and G. latidens. Physogaleus has a similar number. What makes this difficult is there are differences in upper and lower teeth and also differences between male and female. Some authors have synonyimized several of these species while others have kept them separate.  Luckily a recent publication has tried to sort some of this out, at least for teeth from Alabama, but it can be extended to other places. The publication is "Taxonomy and biostratigraphy of the elasmobranchs and bony fishes of the lower to middle Eocene Claiborne Group in Alabama....." Using this publication as a guide, I would call this tooth "Physogaleus alabamensis" which was previously know as G. alabamensis. Here's a screenshot of several specimens from the publication.