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Recently I purchased these two Squalicorax sp. tooths from an auction website and both are currently on the way. I have a few questions about identification since I know very little about shark tooths and also please correct any misidentifications.

 

Seller A sold me this tooth and it was listed as Squalicorax hartwelli. It is collected from Niobrara formation in western Kansas.

 

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Is Squalicorax hartwelli considered a variation of Squalicorax falcatus? Do you agree with seller A's identification above?

 

Seller B sold me this tooth and it was listed as Squalicorax kaupi. It is collected from Lincoln Limestone member of Greenhorn Limestone formation.

 

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I suspect this tooth is misidentified and it should be Squalicorax falcatus, a paleobucket taxa for Squalicorax sp. variations. I thought Squalicorax kaupi is found from Santonian to Maastrichtian and Lincoln Limestone member is Cenomanian. 

 

I spent quite a bit looking up on here and Ocean of Kansas website comparing Squalicorax sp. tooths before posting! Although I am more confident in some of the members' identification skills than I am with mine.

 

Regardless of identifications (or misidentifications), I am happy with both and is excited to have them arrive soon!

 

 

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Really nice teeth. I’ve tried making sense of the different Squalicorax species, but the scientific literature contradicts itself quite a bit. The use of Squalicorax curvatus and Squalicorax falcatus as a paleobuckets has really complicated identification. I believe Squalicorax falcatus is a European species while Squalicorax hartwelli is an American species. Squalicorax curvatus is now defunct and synonymous with either Squalicorax baharijensis or Squalicorax falcatus.

 

For your teeth, I think the one sold to you as “Squalicorax hartwelli” is actually Squalicorax kapui. Looking over the pictures and illustrations of S. hartwelli, I can’t find any teeth that are as large as yours. I believe the tooth sold to you as “Squalicorax kapui” is actually Squalicorax hartwelli. If I’m right, all you have to do is switch the labels. :P

 

Wait and see what other TFF members have to say. Perhaps @Chase_E can help.

 

Regardless of the IDs, great teeth! Kansas Squalicorax are special. They will be great additions to your collection.

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@Darbi Can't help with id, but I just wanted to chime in and congratulate you on the great acquisitions. By the way, the plural of tooth is teeth, which is easier to say than tooths :)

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Greetings from the Lake of Constance. Roger

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On 8/19/2020 at 12:31 AM, Praefectus said:

Really nice teeth. I’ve tried making sense of the different Squalicorax species, but the scientific literature contradicts itself quite a bit. The use of Squalicorax curvatus and Squalicorax falcatus as a paleobuckets has really complicated identification. I believe Squalicorax falcatus is a European species while Squalicorax hartwelli is an American species. Squalicorax curvatus is now defunct and synonymous with either Squalicorax baharijensis or Squalicorax falcatus.

 

For your teeth, I think the one sold to you as “Squalicorax hartwelli” is actually Squalicorax kapui. Looking over the pictures and illustrations of S. hartwelli, I can’t find any teeth that are as large as yours. I believe the tooth sold to you as “Squalicorax kapui” is actually Squalicorax hartwelli. If I’m right, all you have to do is switch the labels. :P

 

Wait and see what other TFF members have to say. Perhaps @Chase_E can help.

 

Regardless of the IDs, great teeth! Kansas Squalicorax are special. They will be great additions to your collection.

Thank you for telling me your opinions and facts, but I don't know if I agree with your opinions. Like what you said about scientific literature contradicting itself, I also found a couple reputable websites that contradicts a part of what you said. You said S. hartwelli is an American species while S. falcatus is an European species, but why did paleontologists referenced in Elasmo on Squalicorax sp. also referred American Squalicorax as both S. hartwellii and S. falcatus? It is the same with Mike Everhart on his website, Oceans of Kansas (Squalicorax sp.). 

A seller who sold me a S. hartwellii tooth is a small, but well-known fossil museum in the western Kansas. Since it's against the rule for me to identify a seller on here and I do not know if that rule also applies to any museum that is a seller, I'll leave its name out. The owners of this small museum are also well-known and took a lot of people on the fossil hunt trips, I would assume they know well about local fossil species and identifications. Since they said it's S. hartwellii, I probably would lean more on their identification for time-being until paleontologists know more about Squalicorax sp. in the future and clears up the confusion on taxonomy.

I do not know anything about a seller who sold me a 'S. kaupi' tooth. I can't say if this seller is a paleontologist, amateur collector, etc. and I cannot gauge this seller's knowledge on fossil identifications. The websites I mentioned above caused me to suspect this seller misidentified the species due to different age of rock formation and where species can be found. Perhaps it's best if I label it as S. falcatus or just Squalicorax sp.?

Thank you for compliments, I really like these teeth regardless what species it actually is!

I hope the members with more knowledge on Squalicorax sp. will chime in!

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On 8/19/2020 at 1:43 AM, Ludwigia said:

@Darbi Can't help with id, but I just wanted to chime in and congratulate you on the great acquisitions. By the way, the plural of tooth is teeth, which is easier to say than tooths :)

Thank you for the compliment and correction! I was thinking 'tooths' as a group but individual teeth and 'teeth' as a group of teeth from a single individual. I'm probably just overthinking. Because of my profound hearing impairment,  the English language is in a way not my native language and I have to iron out some minor grammar misunderstandings. :headscratch:

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Really nice teeth, @Darbi. I vote S. kaupi for the first tooth and S. falcatus for the second. However, my id may be based on a now outdated book. 

On 8/19/2020 at 12:31 AM, Praefectus said:

Squalicorax curvatus is now defunct and synonymous with either Squalicorax baharijensis or Squalicorax falcatus.

Bummer. Now I need to change my display label for S. curvatus. :DOH:

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"Argumentation cannot suffice for the discovery of new work, since the subtlety of Nature is greater many times than the subtlety of argument." - Carl Sagan

"I was born not knowing and have had only a little time to change that here and there." - Richard Feynman

 

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  • 1 year later...

I think that second tooth is closer to falcatus/hartwelli than to kaupi because kaupi is a later species of the Campanian and it tends to have a shorter distal blade.

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