Post Oak Creek Cretaceous Shark Teeth Help

[Peat Burns]

Hello, 

 

Looking for help with these Upper Cretaceous shark teeth from Post Oak Creek, Sherman, Grayson Co., TX, USA (Warning:  Some of these are heavily eroded).

 

Thank you!

 

Squalicorax? Species?

 

 

Cretodus or Cretalamna?  Mix of both?

 

Scapanorhynchus sp?

 

 

@ThePhysicist

Edited October 31, 2023 by Peat Burns

[ThePhysicist]

4 hours ago, Peat Burns said:

Squalicorax? Species?

Indeed crow, I haven't cared to be more precise since some species are wastebaskets. @EPIKLULSXDDDDD may have studied crow species more than I.

 

4 hours ago, Peat Burns said:

Cretodus or Cretalamna?  Mix of both?

Most of these are goblins (ones with a lingual nutrient groove). The 3rd from left on the top row could be ginsu.

 

5 hours ago, Peat Burns said:

Scapanorhynchus sp?

Yes.

[Thomas.Dodson]

Lumping aside, the Squalicorax from the Eagle Ford are typically reported as Squalicorax falcatus.

[Peat Burns]

1 hour ago, ThePhysicist said:

Indeed crow, I haven't cared to be more precise since some species are wastebaskets. @EPIKLULSXDDDDD may have studied crow species more than I.

 

Most of these are goblins (ones with a lingual nutrient groove). The 3rd from left on the top row could be ginsu.

 

Yes.

Thank you very much.

[Peat Burns]

51 minutes ago, Thomas.Dodson said:

Lumping aside, the Squalicorax from the Eagle Ford are typically reported as Squalicorax falcatus.

Thanks very much.

[Mikrogeophagus]

I would just call it Squalicorax sp. The genus is a bit of a mess and much work needs to be done, especially for this portion of the Cretaceous. The better defined species I know of are mostly in the Cenomanian/Albian (S. priscoserratus, S. pawpawensis, S. baharijensis) and some later. If you prefer to put a wastebucket name like S. falcatus that's ok too.

 

Finding a Carcharhinus tooth in Hawaii opened my eyes to the difficulty of naming shark species based off of teeth alone, especially those of generalists such as Squalicorax. Around Hawaii alone, there are a handful of Carcharhinus species that do or do not overlap in habitat/appearance/behavior, yet possess virtually identical tooth morphologies. Even with living representatives, pinning a species level ID to a tooth is near impossible.

 

So for a generalist shark living nearly 100 mya, I doubt we will ever be close to accurately figuring the genus out, unless there is some crazy tech advancement. However, there are subtleties still noticeable even to us. I have a very shallow paleo water depth collecting spot in the Cenomanian that shares many of the same shark species as another deeper locale many miles away. Sharks like Cretodus semiplicatus, Meristodonoides sp., and Onchopristis dunklei are extremely common in the shallower locale as opposed to the deeper one where sharks like Cretoxyrhina agassizensis and Ptychodus spp. prevail. In regards to Squalicorax, there is a much higher occurrence of S. baharijensis in the shallow site as opposed to teeth that share the morphology of what you have pictured which is more so at the deeper one. It's fun to wonder if this phenomenon is akin to the distribution of the blacktip reef shark (C. melanopterus) of modern HI coastal waters versus the gray reef shark (C amblyrhynchos.) which is found in much farther out.

 

Sorry for yapping so much, but this is something I think is nice to wonder about. Hope this was informative!

[ThePhysicist]

2 hours ago, EPIKLULSXDDDDD said:

Finding a Carcharhinus tooth in Hawaii opened my eyes to the difficulty of naming shark species based off of teeth alone

Carcharhinus will certainly do that to a person! 

[Peat Burns]

15 hours ago, EPIKLULSXDDDDD said:

I would just call it Squalicorax sp. The genus is a bit of a mess and much work needs to be done, especially for this portion of the Cretaceous. The better defined species I know of are mostly in the Cenomanian/Albian (S. priscoserratus, S. pawpawensis, S. baharijensis) and some later. If you prefer to put a wastebucket name like S. falcatus that's ok too.

 

Finding a Carcharhinus tooth in Hawaii opened my eyes to the difficulty of naming shark species based off of teeth alone, especially those of generalists such as Squalicorax. Around Hawaii alone, there are a handful of Carcharhinus species that do or do not overlap in habitat/appearance/behavior, yet possess virtually identical tooth morphologies. Even with living representatives, pinning a species level ID to a tooth is near impossible.

 

So for a generalist shark living nearly 100 mya, I doubt we will ever be close to accurately figuring the genus out, unless there is some crazy tech advancement. However, there are subtleties still noticeable even to us. I have a very shallow paleo water depth collecting spot in the Cenomanian that shares many of the same shark species as another deeper locale many miles away. Sharks like Cretodus semiplicatus, Meristodonoides sp., and Onchopristis dunklei are extremely common in the shallower locale as opposed to the deeper one where sharks like Cretoxyrhina agassizensis and Ptychodus spp. prevail. In regards to Squalicorax, there is a much higher occurrence of S. baharijensis in the shallow site as opposed to teeth that share the morphology of what you have pictured which is more so at the deeper one. It's fun to wonder if this phenomenon is akin to the distribution of the blacktip reef shark (C. melanopterus) of modern HI coastal waters versus the gray reef shark (C amblyrhynchos.) which is found in much farther out.

 

Sorry for yapping so much, but this is something I think is nice to wonder about. Hope this was informative!

Very helpful.  Thank you very much.