Unknown Cretaceous find

[coled18]

Hi all,

 

This was found by my brother at he Niobrara chalk earlier in W Kansas.  I have no idea what it is, so could you all help? I am thinking it is a bone fragment of some kind although it has the general shape of a limpet. 

[Miocene_Mason]

I’ve got no idea what this is, so for curiosity’s sake I’m going to follow this thread. Sorry I can’t help, hope someone else can!

[coled18]

I think I found the answer out myself. I think that it is a mostly complete tooth from a Ptychodus Mortoni, a shell-crushing shark that lived in the Late Cretaceous. I am envious of my brothers find!!!

[Fruitbat]

I don't think that's a Ptychodus tooth.  Unfortunately, I'm not quite sure what it IS!

 

-Joe

[doushantuo]

Ptychodus teeth ,and ultrastructure after acidolysis

good depiction of enamel:

 

 

 

 

 

 

 

[doushantuo]

articulated P decurrens/Cretaceous(Cenomanian of Germany):

 

schlotheimii holotype:

 

[doushantuo]

paleoichtyology ,Niobrara(Smoky Hill)

 

Edaphodon,Ptychodus,Johnlongia,Cretalamna,Cretoxyrhina,Pseudocorax,Squalicorax,Micropycbodon,Palaeobalistum,Rhinobatos,Protosphyraena,

Paraliodesmus,Asarotus,Gillicus,Ichthyodectes,Xiphactinus,Prosaurodon,Saurocephalus,Saurodon,Syntegmodus,Niobraria,Martinichthys,Bananogmius

(Pseudo)thryptodus,Plethodes,Zanclites,Dixonanogmius,Palelops,Urenchelys,Apsopelyx,Pachyrhizodus,Leptecodo,Stratodus,Enchodus,Kansius,Omosoma,

Laminospondylus,Aethocephalichthys

 

Some can obviously be ruled out beforehand.

Is it an ichthyolith?

 

[Coco]

Hi,

 

The pics are vague, but that could be a big buckle  of ray ? A plate / patch with a spine above, I don't remember any more the name in English...

 

http://www.paleomania.com/article-boucle-de-raie-dasyatis-du-neogene-d-anvers-122387002.html

 

Coco

[Rockwood]

3 hours ago, doushantuo said:

Is it an ichthyolith?

Has my vote.

[Anomotodon]

I think it is a ray dermal denticle or something similar to Peyeria, that is sometimes considered a Sclerorhynchid dermal denticle rather than a sawfish rostral tooth. Definitely does not look like Ptychodus though.

 

Here is a picture of Rhina ancylostoma (modern guitarfish) spines.

[coled18]

I know that most Ptychodus teeth look fairly different from what I have, and I think that ray denticle is also a possibility, so thank you all for that insight. However, I still think that Ptychodus Mortoni is still an option, since I initially compared my find to these Mortoni teeth found in the same county. My pictures are not of great quality, namely the first one which does leave out a lot of detail. From what I know, Ptychodus teeth fossils are fairly common in the Niobrara chalk, whereas I cannot find anything concerning rays in the in the Smoky Hill chalk layer (I was hunting there). What do you all think? Would more better pictures help?