Fish tail?

[Carl]

I'm with @Pemphix. At first I was thinking it might be a colecanth tail but aptychi is a closer match.

[Ramon]

7 hours ago, Pemphix said:

IMO no fish.

I think ammonite aptychus.

https://de.wikipedia.org/wiki/Datei:Aptychus.jpg

https://www.gettyimages.co.uk/detail/photo/fossil-ammonite-aptychus-high-res-stock-photography/540045226

https://ssl2.cms.fu-berlin.de/geo/v/PM-epal/forschungsschwerpunkte/anatomie/Kieferapparat/index.html

 

Seems like it’s solved!! 

 

Thanks to to everyone for helping id this fossil!! 

[doushantuo]

So

What Lehmann called the "laevaptychus" type?

 

Above:in situ aptychi

below:series of aptychi

 

 

 

 

 

 

 

[herve]

Idem Pemphix

[doushantuo]

Heim(1926**) mentions "Aptychus lamellosus"  for the Sierra Madre Oriental of Mexico(see below)

And as ammonite fauna:

"1. Trail about 1 km East of Tamân: Haploceras
Fialar Oppel'sp., H. transatlanticurn Burckh., Perisphinctes sp.,
Aplychus lamellosus Park.
2. Trail West of La Cuesta: Haploceras Fialar Oppel sp.,
Perisphinctes cyclodorsatus Moesch in Fontannes, Aspidoceras
juv. gr. longispinum Sow., A. cfr. polysarcum Font., A. eligmoplychum
Font., (Aulacomyella lata n. sp.) Upper Kimeridgian.*
3. River bend East of Tamân: Perisphinctes sp. div. ind."

*obviously that is spelled wrongly,But Heim was Swiss ....

**Eclogae Geologicae Helvetiae
Band (Jahr): 20 (1926-1927)
Heft 1
 

[abyssunder]

another vote for aptychus

 

excerpt from P. Zell et al. 2016. Late Jurassic aptychi from the La Caja Formation of northeastern Mexico. Bol. Soc. Geol. Mex. 68(3): 515-536

[doushantuo]

That's the sixth return if you Google "Jurassic aptychus Sierra Madre"

ANYHOOO....

Abyssunder found comparatively recent documentation(particularly "e" in that figure) that pretty much identifies Ramon's find ,I think.

Good call by everyone who spotted the systematic affinity right away!!! 

[KimTexan]

The one thing none of those examples have is a central stalk, which all the lines branch off like the OP pic has. Also, there appear to be transverse lines between the branches. Not sure if that’s artifact. See green circle.

Is what is circled in red suture lines?

Are you able to get a closeup of this area?

 

[Pemphix]

1 hour ago, KimTexan said:

The one thing none of those examples have is a central stalk, which all the lines branch off like the OP pic has. Also, there appear to be transverse lines between the branches. Not sure if that’s artifact. See green circle.

Is what is circled in red suture lines?

Are you able to get a closeup of this area?

 

 

Hi Kim,

What you see is the negative (imprint) not the positive - some structures may not be viewable in the negative.

Furthermore not every (Lamell-) Aptychus has the very same morphology/anatomy.

And at least the fossil is not well preserved - the uppermost part of it is missing/not visible (see pic a1, a2 in abyssunder pics for details - that's one complete half of a Lamellaptychus). 

The central stalk is very good visible in the overview photo imo (if we're talking about the same structure).

 

 

[Pemphix]

On 24.12.2018 at 5:48 PM, doushantuo said:

So

What Lehmann called the "laevaptychus" type?

 

Above:in situ aptychi

below:series of aptychi

 

 

 

 

 

 

 

I know that type of aptychus as "Lamellaptychus"...:

http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=86697

https://science.mnhn.fr/taxon/genus/Lamellaptychus

https://books.google.de/books?id=LxPmBQAAQBAJ&pg=PA16&lpg=PA16&dq=lamellaptychus&source=bl&ots=mFbMVyew62&sig=8rxO3cebKPX-fGTNGi8AkxJJHrw&hl=de&sa=X&ved=2ahUKEwjJwpSH_LzfAhXOJlAKHdsaDCI4ChDoATAHegQIBBAB#v=onepage&q=lamellaptychus&f=false

https://www.zobodat.at/pdf/VeroeffFerd_81_0093-0105.pdf

[doushantuo]

The two photographs weren't meant to illustrate Lehman's concept(ion) of laevaptychus 

Some of you may like:

dsdp44_40.pdf

APTYCHI (AMMONOIDEA) FROM THE EARLY CRETACEOUS OF THE
BLAKE-BAHAMA BASIN, LEG 44, HOLE 391C, DSDP
Otto Renz

Init.Rep.DSDP/leg 44/ch.40

BOTH line drawings and photographs