Cretaceous Sharks

[Sélacien34]

Thank you for your help Jess, it really helps.

I don't think that tooth is haigi because i don't see folds on the lingual face.

That's true, even if the shape is very close. Thus i will name it Archaeolamna sp.

Another one like mine from the French Albien of Wissant :

Yes, I was unsure of the striatula identification and wondered if your tooth is worn. I could not match it to anything.

It doesn't appears to be worn, no more idea for this time either. I have seen a representation of Scapanorynchus raphiodon (not "prae" here) with a smooth lingual face in Occasional Papers of the Dallas Paleontological Society, that doesn't correspond to the diagnosis of Siversson.

It's close to mine with a narrow triangular crown, but it seems that it's a problematic taxa, in any case, i don't know exactly what it is.

I think the "early Cretodus" tooth follows the form of Cretodus but it may be a different species from semiplicatus because it does not have lingual folds. It is difficult to say because I have seen so few Cretodus teeth. If your tooth is Cretodus, it is the oldest one I have seen

That's right, the lingual surface is smooth. Ward describes C. semiplicatus from the Albian of UK, the roots are closer but it has lingual folds and longer and narrower cusplets. The french Cretodus semiplicatus has closer cusplets but lingual folds too. It doesn't match, so it seems that it's an other sp.

About the tooth that looks like Cretoxyrhina, it could have wore cusplets, the two sides of the crown are worn, it shows something like broken part on the 2 sides.

My tooth came from the Albian, but the shape of the tooth seems very close with Cretoxyrhina mantelli that came later in late Cretaceous. About the previous forms, like C. vraconensis from late Albian, the positions that i have seen and the diagnosis of Ward that i have read that describes large teeth, large triangular crown and large and well separated round or triangular cusplets, seems to be different from mine. I tried to compare it to C. mantelli, all from late Cretaceous, it looks close, i don't know what to think about that.

Cretoxyrhina seems to be the only candidat and it seems that it has been found in French Albien :

it is away from your home but the interest is eventually to know the first occurence

Lower Cretaceous of Wissant :

There also has lamellibranches as plicatula, Bankia (pectinata albensis, planata) of Protocardia, corals as Trochocyathus, Parasmilia, Neithea, Lucina, Entolium and brachiopods, as Burrirhynchia, Praelongithyris, Loriothyris, Cyclothyris deluci, Moutonithyris dutempleana, worms as Glomerula, Rotularia, and dental as well as very rare shark teeth of Cretoxyrhina type crabs Etyus martini and Notopocorystes stockesi, crinoids ...

This one, 5 cm, is from the Albien of Alpes de Hautes Provence

I haven't even thought to Cretalamna about the last tooth, yet it is a good track with these cusps shaped like cat ears but despite that i haven't found anything really close to it in Cretalamna, It looks vaguely to some positions of Cretalamna sarcoportheta sp. but this specie is from the early Campanien, the lobes of the root are too short on Cretalamna for all anterior positions from all species. It's seems that my tooth is closer from Dwardius from French Albien that have the same type of cusplets but they are under the base of the crown and well separated on my tooth. Nothing looks like to that tooth or i haven't found it yet, i will try to ask to M. Siversson.

Dwardius siversoni

Cretalamna sarcoportheta sp. Crown is too large or cusplets are not enough separated, not from Albian

Edited May 4, 2014 by Sélacien34

[Sélacien34]

No, I don't have a figure for an Archaeolamna dentition. It is a genus that ranges from the Early to Late Cretaceous and no natural dentitions are documented so it isn't always clear what you have. You have to piece together an image in your own mind from teeth from various articles and then leave room for variation. Siverson's 1992 and 1996 papers have helped me.

I don't think that tooth is haigi because i don't see folds on the lingual face.

Yes, I was unsure of the striatula identification and wondered if your tooth is worn. I could not match it to anything.

I think the "early Cretodus" tooth follows the form of Cretodus but it may be a different species from semiplicatus because it does not have lingual folds. It is difficult to say because I have seen so few Cretodus teeth. If your tooth is Cretodus, it is the oldest one I have seen

As for the last two teeth, the first one could be an early Cretoxyrhina but one that old would be expected to exhibit at least weak lateral cusplets.and your tooth seems very slender for that genus of that time. I think the second tooth could be an early Cretalamna.

Jess

Siverson, M. 1992

Biology, Dental Morphology and Taxonomy of Lamniform Sharks from the Campanian of the Kristianstad Basin, Sweden. Paleontology. Vol. 35 (3): 519-554.

Siverson, M. 1996.

Lamniform sharks of the Mid Cretaceous Alinga Formation and Beedagong Claystone, Western Australia. Palaeontology. 39 (4): 813-849.

Hi Jess, i have found a C. vraconensis from Albian / mid Cenomanian on the forum that came from North Texas-South Oklahoma. It seems that it was identified by an expert and It looks rather close to my tooth, I gave here to my tooth the cusplets that it is possible that it had, taking into account the sides which show a break. what is your opinion about it?

An other tooth for which i would like your opinion, it's came from the Albian of Kursk/Russia : 3,1 cm (diagonal)

Edited May 6, 2014 by Sélacien34

[Vball]

Sorry guys the C. vraconensis was not verified by the expert. That was from my collection and was my best guess. The Expert thought Dwardius siversoni or Archaeolamna but was not real sure. He studied the northern part of the seaway in Canada so he hadn't seen some of the teeth I had from Tx/Okl the southern part.

My problem was i had some different ones that were also IDed as Archaeolamna. The three I have match almost perfect to my slightly younger Cretoxyrhina teeth only with cusps. Case listed the C. vraconensis from this formation and I couldn't find any examples so I guessed. I am waiting for a good solid ID for them. After seeing this thread I'm leaning towards Dwardius siversoni for mine as well. Wish I could find a picture with more examples.

[Sélacien34]

Hi Vball , don't be sorry and thank you for your message that enlighten me a bit. So your tooth is probably not C. vraconensis , actually I couldn't find for my tooth the right elements of diagnosis described by Zhelezko who also said that these teeth are often confused with Dwardius and Cretolamna .

About D. siversoni he also said that these teeth are very difficult to distinguish from Archeolamna as you mentioned . Knowing more than your tooth comes from Texas Southern Oklahoma and mine of France , and mine has lost its cusps . D. siversoni have also been listed in the French Albian . The pictures corresponding to anterior teeth of Dwardius siversoni seem to have thicker roots, I do not know if that would be suitable for my tooth but it may be the solution. Please keep me informed if you learn more or you get other opinions about your tooth.

The last one I have presented ​​is supposed to be Cretalamna borealis .

Edited May 10, 2014 by Sélacien34

[MikaelS]

This is probably a relevant publication.

http://www.tandfonline.com/doi/abs/10.1080/03115518.2012.709440#.U3g6YcKKDIU

[Sélacien34]

Hello Mikael, thank you very much for your answer, i think that is obviously a very relevant publication. I would have to see it, thank you again. Mid-Cretaceous Cretoxyrhina (Elasmobranchii) from Mangyshlak, Kazakhstan and Texas, USA

Edited June 7, 2014 by Sélacien34