Stenopoceras, nautiloid from the Finis Shale of Texas

[BobWill]

I found my first Stenopoceras sp. from the Finis Shale member of the Graham Formation at Jacksboro Texas. I thought it was an oddly-shaped version of the more common Grypoceratid from there, Domatoceras scuptile until I noticed the concave venter. I went through my drawer of Domatoceras fragments and found another partial one after I studied the differences a little. That one was just part of one side and had nothing of the venter but a part of the apertural margin was showing, something I don't remember seeing before. Both are external casts so no sutures but the faint growth lines are visible.

 

The phragmocone is crushed and I believe the septum is the last one so most of the specimen is the body chamber which is about 67mm across. Those holes sure look like punctures and the shell is mostly gone from the opposite flank.

 

 

This view shows the crushed phragmocone and the septum for a look at the whorl profile which is taller than the more "squatty" Domatoceras.

 

 

It was in about 7 pieces and I just now figured out where the last one fit. I hope I got all of it that was still there.

 

 

[DPS Ammonite]

The Pennsylvanian rocks including the limestone cap at Jacksboro continue to amaze me. Where else have they found roughly 200-300 species in such a small area of Paleozoic rock? In Arizona they have found in the similar aged Pennsylvanian Naco Fm. (mostly undescribed) less than half the number of species over the entire area of the Naco’s cropping out. 
 

@BobWill can you take a stab at the likely total number of species of fossils found at the Jacksboro spillway site including the caping layer of limestone with all the coral fossils? Don’t forget the forams and   ostracodes: the ones that mortals can’t ID.

[BobWill]

2 hours ago, DPS Ammonite said:

 

@BobWill can you take a stab at the likely total number of species of fossils found at the Jacksboro spillway site including the caping layer of limestone with all the coral fossils? Don’t forget the forams and   ostracodes: the ones that mortals can’t ID.

Yes John, I have seen and heard some estimates. Mark McKinzie had close to 150 on the fauna list in his Color Guide, Dr. Barbara Seuss of Germany has listed 292 in the paper on the new lagerstäte and Dr. Neuman who is helping with out study group says that it may reach or even exceed 400 once we include the microfauna. Of course this is still not huge compared to some sites like Solnhofen at 1544, Cassian at 1517, White Chalk of Rugen at 1348, Mazon Creek at 815 and London Clay at 584 but still staggering compared to most sites.

[DPS Ammonite]

16 minutes ago, BobWill said:

Yes John, I have seen and heard some estimates. Mark McKinzie had close to 150 on the fauna list in his Color Guide, Dr. Barbara Seuss of Germany has listed 292 in the paper on the new lagerstäte and Dr. Neuman who is helping with out study group says that it may reach or even exceed 400 once we include the microfauna. Of course this is still not huge compared to some sites like Solnhofen at 1544, Cassian at 1517, White Chalk of Rugen at 1348, Mazon Creek at 815 and London Clay at 584 but still staggering compared to most sites.

Thanks Bob. You are the Shell Answer Man of the paleontology world. You also anticipated a question that I had in my mind: how many species have been found in other lagerstatten.
 

Has anyone included the several species of plant seeds found at Jacksboro in their counts? I remember that Virginia Friedman had a nice collection.

 

Keep us informed about Suess’ and Neuman’s findings and papers. Their works are useful for IDs of Pennsylvanian fossils in Arizona and other states. 

[BobWill]

12 minutes ago, DPS Ammonite said:

 

Has anyone included the several species of plant seeds found at Jacksboro in their counts? I remember that Virginia Friedman had a nice collection.

 

Keep us informed about Suess’ and Neuman’s findings and papers. Their works are useful for IDs of Pennsylvanian fossils in Arizona and other states. 

Those totals include plants and the numbers for them are growing too.  Virginia probably has the most plant specimens but I don't know how may species she has.

I will post a link to our website when we get it up and running and anything else I get from Barbara.