Any Permian/Carboniferous shark experts?

[fossilized6s]

Found this last Sunday. And i can't seem to narrow down who lost it, Xenacanthus or Orthacanthus. To my knowledge neither has been formally described from the location it was found. And, no, i will not say where. I'll simply say LaSalle county, IL. Still not sure if my site is Permian or Carboniferous. I'm 90% convinced it's Carboniferous. 

 

Any ID help is much appreicated. I'm leaning more towards Orthacanthus. 

 

Sorry, i'll add mm later. 

 

As found:

 

 

After some needle prep:

 

 

 

 

 

 

[old bones]

Wow, that's different, Charlie! 

[ynot]

Nice find!

The Xenacanthus teeth I have seen do not have serrations, as Yours does.

 

[fossilized6s]

1 hour ago, ynot said:

Nice find!

The Xenacanthus teeth I have seen do not have serrations, as Yours does.

 

I agree. But all of the Orthacantus i have in my collection don't either, but they're from Oklahoma. Maybe this just has a better preservation.....idk.

[Innocentx]

Great find.

Here's one from Oklahoma that does have serrations.

 

 

 

[westcoast]

That's a beauty!

[fossilized6s]

@Archie do you have an opinion? 

[fossilized6s]

Is the difference in tooth morphology between these two sharks basically size?

 

Does anyone know of any defining characteristics that would help narrow this down? 

[JimB88]

Yes, they can have serrations. Awesome find too btw!

[doushantuo]

The major resource/baseline papers for xenacanthid dentition might be miscellaneous papers by Schneider in the Freiberger Forschungshefte*.

(Xenacanthids being a well-known constituent of the Permo-Carboniferous ichthyofauna of Middle Europe)

Also.I think Pfeil authored a hefty monograph on Carboniferous-Permian sharks ,in 1983.

All of the above are in German,I think,which MIGHT limit their usefulness?

Are these papers hard to get?

You bet

*edit:

SCHNEIDER, J.W. & ZAJIC, J. 1994. Xenacanthiden (Pisces:
Chondrichthyes) des mitteleuropaeischen Oberkarbon und
Perm - Revision der Originale zu GOLDFUSS, 1847,
BEYRICH, 1848, KNEe, 1867 und FRITSCH, 1879-1890.-
Freiberger Forschungshefte, (C) 452: 101-151, 31 Abb., 3
Taf., Leipzig.

 

 

 

[deutscheben]

Very cool find! I have found a half dozen different genera of shark teeth in LaSalle County, but no xenacanth teeth. I'm not an expert, but from my reading it seems like there can be quite a bit of variation within the species as well as between Orthacanthus and Xenacanthus. This paper talks a little bit about the morphology of O. compressus teeth, though, it might be useful: https://research-information.bristol.ac.uk/files/91128395/OGoghain_2016.compressed.pdf

[doushantuo]

Same source as above(Hampe/Trans.RS Edinburgh):

 

johnson 1999*

*Being free access,this paper is probably in several libraries here(4,1 Mb)

 

[jdp]

Yeah that's Orthacanthus.

 

Neat specimen; Carboniferous vertebrates are rare in Illinois outside of Mazon and the black shales. Do you get other vertebrate material from this locality?

[Archie]

Awesome find! Really gorgeous tooth and great needle work. The literature I have seems to indicate the difference is that Orthacanthus have serrations and Xenacanthus do not.

[fossilized6s]

On 7/4/2018 at 8:55 AM, jdp said:

Yeah that's Orthacanthus.

 

Neat specimen; Carboniferous vertebrates are rare in Illinois outside of Mazon and the black shales. Do you get other vertebrate material from this locality?

Thanks. I did find a bone block associated with crinoids, nautiloids, denticles and possible cartilage. 

 

5 hours ago, Archie said:

Awesome find! Really gorgeous tooth and great needle work. The literature I have seems to indicate the difference is that Orthacanthus have serrations and Xenacanthus do not.

 

Thanks. I'm almost positive this is Orthacanthus. 

[jdp]

Any pics of that bone block? Scientific interest.

[fossilized6s]

2 hours ago, jdp said:

Any pics of that bone block? Scientific interest.

It really deserves it's own topic, but here are a few teasers. 

 

 

 

 

[jdp]

Very interesting. Keep me posted, especially as prep progresses. 

 

Is this in Francis Creek Shale in a non-nodule layer? Or is it something else e.g. McLeansboro Formation?

[fossilized6s]

It's from somewhere else. I haven't narrowed down a formation yet. Narrowed it down to Upper Pennsylvanian though.

[RCFossils]

Nice finds Charlie!

There is quite a bit of shark material in the limestone and black Shale in the areas you are collecting.

i would agree with others that your tooth is from an Orthacanthus. I do not recall having seen any others from that area.

Tetrapod bones and teeth can also be found in the area you are collecting.

 

 

[fossilized6s]

Thanks everyone.

 

I'm 99.9% sure the tooth is Orthacanthus. And mostly likely the first example of this species from the fauna.

 

I'll post a whole new topic on my other item. I'm pretty convinced the bones are from a Tetrapod of some sort. Definitely something big and boney from the Permocarboniferous.