Strange Cretaceous thing

[truceburner]

Here's a little puzzler I found recently. Seems somewhat shell-like on one side, bumpy texture on the other. Shell or something else? Opinions appreciated.

[ashcraft]

Scute of some kind?

 

Brent Ashcraft

[truceburner]

That crossed my mind, @ashcraft. Someone will be familiar with the texture. Could it be turtle?

[JohnJ]

Does the edge show any kind of laminated structure?  I'm inclined to think this is a Cretaceous shell fragment with some kind of encrusting bryozoan on the opposite side.  I don't see anything to make me think this a vertebrate fossil of any kind.

[ynot]

I agree with John.

Tony

[Rockwood]

7 hours ago, JohnJ said:

Does the edge show any kind of laminated structure?  I'm inclined to think this is a Cretaceous shell fragment with some kind of encrusting bryozoan on the opposite side.  I don't see anything to make me think this a vertebrate fossil of any kind.

Couldn't the bumpy texture also be a calcareous algae ? 

[fifbrindacier]

I agree it looks to be a piece of shell, and, on the other face, maybe a stromatoporoid or another kind of sponge.

[truceburner]

20 hours ago, JohnJ said:

Does the edge show any kind of laminated structure?  I'm inclined to think this is a Cretaceous shell fragment with some kind of encrusting bryozoan on the opposite side.  I don't see anything to make me think this a vertebrate fossil of any kind.

No laminar structure discernible from the edge.

[abyssunder]

 mamelons and astrorhizae ?

http://palaeos.com/metazoa/porifera/stromatoporoidea.html

 

[truceburner]

[fifbrindacier]

16 hours ago, fifbrindacier said:

I agree it looks to be a piece of shell, and, on the other face, maybe a stromatoporoid or another kind of sponge.

 

3 hours ago, abyssunder said:

 mamelons and astrorhizae ?

http://palaeos.com/metazoa/porifera/stromatoporoidea.html

 

I confirm, to me it is a stromatoporoidea.

[Rockwood]

I think we all just got sent back to the proverbial drawing board ! 

[Al Dente]

The bumpy surface reminds me of an ammonite aptychus. Not so sure the other side resembles one.

 

Here is an aptychi from the Oceans of Kansas website-

 

 

[abyssunder]

I could see that.

A Spiny Aptychus from the Cretaceous of Kansas - Alfred G. Fischer and Robert O. Fay Here

 

 

[DPS Ammonite]

29 minutes ago, abyssunder said:

I could see that.

A Spiny Aptychus from the Cretaceous of Kansas - Alfred G. Fischer and Robert O. Fay Here

 

 

Abyssunder nailed it. The fossil in questions looks like the inner and outer surface of the  spiny Aptychus as shown in photos of A and B.

[Carl]

Ooooh! Learned something cool! I'd never have been able to come up with aptychus. Must save this search image in my head... Great job, folks!

[truceburner]

Oh my! Y'all have been busy solving this mystery! Thanks @Al Dente! More info on the unknown-to-me structure and it's purpose: http://www.sciencedirect.com/science/article/pii/S0016699514000023

[truceburner]

For me, image 'd' in @abyssunder's post settles it. The little dots at the top of the bumps are visible with a loupe. So cool! Thanks all.

[doushantuo]

parentwestermammonitmolluscgeobios3-main.pdf

[doushantuo]

I suggest googling the names Kruta,Seilacher,Farinacci,Schweigert,Lomax,Reboulet,Tamaba and Turek.

E.g.:

http://www.geo.fu-berlin.de/geol/fachrichtungen/pal/eigenproduktion/Band_10/21_Schweigert.pdf

And:Fruitbat's Library.,on this very forum,prabably has loads on aptychi

some Tanabe:

 

Tanabe 2012aptych (N Jb Geol Palaont Abh).pdf

[doushantuo]

Aptychi in core:

http://www.deepseadrilling.org/41/volume/dsdp41_07.pdf

rhyncholites:

http://www.zobodat.at/pdf/ANNA_112A_0627-0658.pdf

and lest i forget,Kudo's to Al Dente 

[fifbrindacier]

Good ID Al Dente.

[fossiling]

On Thursday, November 03, 2016 at 10:55 AM, doushantuo said:

I suggest googling the names Kruta,Seilacher,Farinacci,Schweigert,Lomax,Reboulet,Tamaba and Turek.

E.g.:

http://www.geo.fu-berlin.de/geol/fachrichtungen/pal/eigenproduktion/Band_10/21_Schweigert.pdf

And:Fruitbat's Library.,on this very forum,prabably has loads on aptychi

some Tanabe:

 

Tanabe 2012aptych (N Jb Geol Palaont Abh).pdf

i've been searching for this legendary pdf library . Do you have a link?

[doushantuo]

yes,but the simplest thing would be to go to "Documents".

 

[truceburner]

I found two more partial Ammonite aptychi today, on the left and right in this picture, original  specimen at center.

 

Glad to know what they are now.