Cretaceous Shark Tooth from Kansas... Archeolamna perhaps ??

[fossilsonwheels]

I am not sure what species this Cretaceous shark tooth belonged to. It comes from Kansas but I really do not have much more information. It is 2 cm on the slant. It is really a nice tooth and it was a bargain. My best guess is Archeolamna which I believe is found in the chalk in Kansas. I do not think it is robust enough to be Cardabiodon and I do not know what other species it would match from the area.  Any help would be appreciated.

[The Amateur Paleontologist]

Is the tooth definitely from the Niobrara Chalk of Kansas?

-Christian

[Anomotodon]

I would go with Scapanorhynchus sp. for this one, although a labial side picture would help the ID.

[fossilsonwheels]

50 minutes ago, The Amateur Paleontologist said:

Is the tooth definitely from the Niobrara Chalk of Kansas?

-Christian

Christian- No. That is how it was labeled but it looks different from the Cretoxyrhina and Ptychodus teeth I have from Kansas. I actually think it may be from Texas.

[fossilsonwheels]

49 minutes ago, Anomotodon said:

I would go with Scapanorhynchus sp. for this one, although a labial side picture would help the ID.

I will get one up tomorrow.

[Innocentx]

This page may help, if you haven't seen it already.

 

http://oceansofkansas.com/ks-sharks.html

[The Jersey Devil]

It’s a Scapanorhynchus upper lateral.

[KansasFossilHunter]

I'm really not so sure on the Scapanorhynchus ID. The ones I've found in the Kansas chalk have been very small and narrower than this one. Here are some other tri-cuspate teeth from the chalk that I haven't identified but they seem somewhat similar to the one in question. Thoughts?

 

 

I also think the two teeth in the lower part of the picture may be different than the top tooth (which seems to have more distinct cusps). 

 

-KS

[KansasFossilHunter]

13 hours ago, Innocentx said:

This page may help, if you haven't seen it already.

 

http://oceansofkansas.com/ks-sharks.html

 

Great resource!  Compare between the Scapanorhynchus seen on Oceans of Kansas vs the one in question here.

[The Jersey Devil]

34 minutes ago, KansasFossilHunter said:

I'm really not so sure on the Scapanorhynchus ID. The ones I've found in the Kansas chalk have been very small and narrower than this one. Here are some other tri-cuspate teeth from the chalk that I haven't identified but they seem somewhat similar to the one in question. Thoughts?

 

 

I also think the two teeth in the lower part of the picture may be different than the top tooth (which seems to have more distinct cusps). 

 

-KS

 

The first tooth is a Cretalamna.

[MikaelS]

The bottom two are juvenile Cretoxyrhina. Need a basal view of the root as well as a profile view to give a meaningful opinion on the Cretalamna tooth. What do you mean by 'Kansas Chalk'? Do you mean the Greenhorn or perhaps the Smoky Hill Chalk? 

[The Jersey Devil]

12 hours ago, MikaelS said:

The bottom two are juvenile Cretoxyrhina. Need a basal view of the root as well as a profile view to give a meaningful opinion on the Cretalamna tooth. What do you mean by 'Kansas Chalk'? Do you mean the Greenhorn or perhaps the Smoky Hill Chalk? 

 

Are the basal and profile views most helpful with judging just the thickness of the tooth or are there other factors that those views help with? Are the two smaller teeth Cretoxyrhina juveniles because of the distinct reduced cusplets and more V-shaped, angled root lobes (moreso than in many Cretalamnas)?

[fossilsonwheels]

A couple of different views of the tooth. I compared quite a bit and I am fine going with the majority opinion that it is Scapanorhynchus.

[TNCollector]

I don't agree with the Scapanoryhynchus ID, I think it is Cretalamna. It does not have the deep nutrient groove in the root that Scapanoryhynchus has.

[MikaelS]

12 hours ago, The Jersey Devil said:

 

Are the basal and profile views most helpful with judging just the thickness of the tooth or are there other factors that those views help with? Are the two smaller teeth Cretoxyrhina juveniles because of the distinct reduced cusplets and more V-shaped, angled root lobes (moreso than in many Cretalamnas)?

Well the root is very important for correct identification of Cretalamna species. It needs to be well preserved though.

https://www.app.pan.pl/archive/published/app60/app20120137.pdf

Bit difficult to explain why those two are Cretoxyrhina. To me its very obvious as identifying Cretaceous shark teeth is literally my profession. Cusplet shape is one character that sets them apart though. If you cleaned them properly (i.e. removed all chalk used strongly buffered acetic acid) you would also notice other differences, such as labial vascularisation and the very thin enameloid towards the root/crown boundary in Cretoxyrhina.

[MikaelS]

1 hour ago, TNCollector said:

I don't agree with the Scapanoryhynchus ID, I think it is Cretalamna. It does not have the deep nutrient groove in the root that Scapanoryhynchus has.

That's probably because the root is so corroded.

[Macrophyseter]

2 minutes ago, MikaelS said:

Bit difficult to explain why those two are Cretoxyrhina. To me its very obvious as identifying Cretaceous shark teeth is literally my profession. Cusplet shape is one character that sets them apart though. If you cleaned them properly (i.e. removed all chalk used strongly buffered acetic acid) you would also notice other differences, such as labial vascularisation and the very thin enameloid towards the root/crown boundary in Cretoxyrhina.

For C. mantelli (and maybe C. agassizensis?), is it a distinguished characteristic that the teeth that posses lateral cusplets have them in more blunt form, like they're not pointy compared to those found in sharks like Cretalamna? What are usually the major dental morphological differences between a juvenile and adult C. mantelli besides frequency of lateral cusplets?

 

 

[Praefectus]

@fossilsonwheels

 

I believe your tooth came from Carcharias amonensis. I'm not 100% certain on that ID. Your tooth is too wide too wide for Scapanoryhynchus. I don't think your tooth is Cretolamna. Cretolamna have more rectangular roots with equilateral-triangle shaped cusps. The curve at the tip of the blade also doesn't support Cretolamna. 

[Anomotodon]

54 minutes ago, Praefectus said:

@fossilsonwheels

 

I believe your tooth came from Carcharias amonensis. I'm not 100% certain on that ID. Your tooth is too wide too wide for Scapanoryhynchus. I don't think your tooth is Cretolamna. Cretolamna have more rectangular roots with equilateral-triangle shaped cusps. The curve at the tip of the blade also doesn't support Cretolamna. 

 

Haimirichia amonensis teeth are completely different - compare with this associated dentition, in addition it is unknown from Coniacian (Kansas Smoky hill chalk) - Campanian (Texas formations, preservation looks quite similar) interval. This is a Scapanorhynchus lateroposterior.

 

[MikaelS]

2 hours ago, Macrophyseter said:

For C. mantelli (and maybe C. agassizensis?), is it a distinguished characteristic that the teeth that posses lateral cusplets have them in more blunt form, like they're not pointy compared to those found in sharks like Cretalamna? What are usually the major dental morphological differences between a juvenile and adult C. mantelli besides frequency of lateral cusplets?

 

 

In C. mantelli cusplets are occasionally present in juvenile lateroposterior teeth (using my 1999 terminology). Also the anterior teeth are broader and more robust in large individuals. Those two small teeth look more like Greenhorn Limestone (Fairport Mb) than Smoky Hill Chalk. If so it would be C. agassizensis (imo). In this species anterior teeth of small individuals often have incomplete cutting edges (not reaching the base of the cusp). Lateral cusplets are commonly present in lateroposterior teeth of this species; usually with an angular apex and the outer cutting edge much longer than the inner one. In the older C. denticulata, lateral cusplets are more commonly rounded. The type material of C. denticulata is most likely upper part of the lower Cenomanian (give or take half a sub-stage). Contrary to popular belief the largest C. mantelli are not of Smoky Hill Chalk age but of mid- to late Turonian age. Its just that these really large individuals are not present in the WIS in the Turonian but they do occur in Europe.

[Macrophyseter]

15 minutes ago, MikaelS said:

Its just that these really large individuals are not present in the WIS in the Turonian but they do occur in Europe.

Speaking of large European individuals, in your 2012 talk at the Royal Tyrrel Museum, you stated that fossils of large Cretoxyrhina individuals outside of the WIS could reach "up to 8, possibly 9 meters". As far as my knowledge goes, the only Cretoxyrhina fossil I currently know of that suggests a length of 8+ meters is NHMUK PV OR 4498, the syntype mentioned in Newbrey et al. (2015). Out of curiosity, are there any other Cretoxyrhina fossils that also suggests these larger lengths?

[MikaelS]

5 hours ago, Macrophyseter said:

Speaking of large European individuals, in your 2012 talk at the Royal Tyrrel Museum, you stated that fossils of large Cretoxyrhina individuals outside of the WIS could reach "up to 8, possibly 9 meters". As far as my knowledge goes, the only Cretoxyrhina fossil I currently know of that suggests a length of 8+ meters is NHMUK PV OR 4498, the syntype mentioned in Newbrey et al. (2015). Out of curiosity, are there any other Cretoxyrhina fossils that also suggests these larger lengths?

Based on cusp size that tooth would have been roughly 80mm in height, which is huge by Cretoxyrhina standards. There is a paper in press on multiple Turonian Cretoxyrhina (associated remains) from Italy (Cretaceous Research). All them are large to very large. Not quite as large as the English syntype but the average size of Cretoxyrhina in offshore mid-to late Turonian chalks of Europe is considerably larger than in the Smoky Hill Chalk.

[fossilsonwheels]

I love the Cretoxyrhina conversation that sprouted from the tooth ID. It is really informative !!! Thanks to everyone for the information and thoughts about my tooth.

[The Jersey Devil]

21 hours ago, MikaelS said:

Well the root is very important for correct identification of Cretalamna species. It needs to be well preserved though.

https://www.app.pan.pl/archive/published/app60/app20120137.pdf

Bit difficult to explain why those two are Cretoxyrhina. To me its very obvious as identifying Cretaceous shark teeth is literally my profession. Cusplet shape is one character that sets them apart though. If you cleaned them properly (i.e. removed all chalk used strongly buffered acetic acid) you would also notice other differences, such as labial vascularisation and the very thin enameloid towards the root/crown boundary in Cretoxyrhina.

 

Thanks for the explanation and the link to your paper. What species would you say the latest Campanian Cretalamna teeth of New Jersey are? There’s definitely more than just one or two species.

[MikaelS]

I have seen evidence for at least two species of genuine Cretalamna in the middle to late Campanian of the eastern coastal plain area. One is either C. borealis or possibly C. bryanti (would need basal views to separate them) and the other is intermediate in time and morphology between C. sarcoportheta and C. lata. It is possible that there are three species (C. sarcoportheta/lata, C. borealis and C. bryanti). Please note that this is based on examination of photographs as opposed to first hand examination of actual specimens (which adds an additional element of uncertainty). I would have been in a much better position to answer your question if this was part of a research project of mine (but then of course I would have said nothing until the work was published).

 

I don't think I would go as far as saying that there is definitely more than two at this stage.