Coniacian Glyptoxoceras?

[Heteromorph]

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[Heteromorph]

A few weeks ago I was able to get online access to T. Villamil 1996 and to acquire a hard copy of Otto Renz's The Cretaceous Ammonites of Venezuela , both of which contain very helpful information on early Turonian occurrences of Glyptoxoceras cf. G indicum in Venezuela and Columbia. They both indicate that Glyptoxoceras occurs with some level of consistency in these horizons, possibly even being considered common or at least not very rare. 

 

In T. Villamil 1996, Glyptoxoceras cf. G. indicum is reported from Columbian and Venezuelan fossil beds extremely rich in small anomiid bivalves, specifically Anomia minuta and Anomia colombiana measuring at max lengths of 6 mm and 8 mm respectively. In these beds, the matrix is made up almost entirely of these tiny anomiids. This paper doesn't have any pictures or description of the Glyptoxoceras specimens, but it does give a lot of useful stratigraphic context that firmly places this genus' origins at least as far back as the early Turonian. See Figs 1-9 for more detail. 

 

I wasn't able to find an online copy of O. Renz 1982, so I bought a hard copy and scanned the relevant pages. This book has pictures of two Glyptoxoceras cf. G. indicum specimens (Figs 13-14) and describes them. In the pictures, around both specimens you can see dozens of tiny anomiids, showing that these likely came from the same horizons described in T. Villamil 1996. I had to edit the original plate into two halves because the file size would be too large all in one piece, but the view of the Glyptoxoceras specimens is not affected. See Figs 10-15 for more detail.   

 

 

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[The Amateur Paleontologist]

@Heteromorph Recently rediscovered this thread  I find Glyptoxoceras a fascinating ammonite - love what you're doing! You seem to be carrying out a really interesting investigation. Hope it produces good results!

-Christian 

 

[Heteromorph]

3 hours ago, The Amateur Paleontologist said:

@Heteromorph Recently rediscovered this thread  I find Glyptoxoceras a fascinating ammonite - love what you're doing! You seem to be carrying out a really interesting investigation. Hope it produces good results!

-Christian 

 

Thank you very much! Hopefully I can soon post some of my other finds from this formation as well. 

 

For now, here are two Scaphites semicostatus specimens, the second showing sutures, and a Cretolamna appendiculata. All from the same horizon as my Glyptoxoceras, along with about 8 other ammonite genera.

 

[GriffinStorm]

I had this specimen identified as Glyptoxoceras. It was found in the North Sulphur River north of Ladonia, TX just on top of the Ozan formation. It appears to even show the bulbous tail. This specimen is completely flat.

[Fossildude19]

8 minutes ago, GriffinStorm said:

I had this specimen identified as Glyptoxoceras. It was found in the North Sulphur River north of Ladonia, TX just on top of the Ozan formation. It appears to even show the bulbous tail. This specimen is completely flat.

 

 

What is the size of this specimen?