Phosphatic Concretions Of The Pennsylvanian Muncie Creek Shale

[Roz]

WOW, I had to look at those images numerous times! What a treat to see what looks like

hundreds of fossil denticles.. Seeing the internal structure is a always fantastic! I am glad you

decided to check things out with your microscope..

[Roz]

Maybe it's possible to tell what kind of shark had those denticles..

[Missourian]

On 6/24/2013 at 4:46 AM, Roz said:

WOW, I had to look at those images numerous times! What a treat to see what looks like

hundreds of fossil denticles.. Seeing the internal structure is a always fantastic! I am glad you

decided to check things out with your microscope..

 

On 6/24/2013 at 9:11 AM, Roz said:

Maybe it's possible to tell what kind of shark had those denticles..

 

Yeah, those took me by surprise. I figured the covering was the exterior of a massive 'bone', or perhaps part of the concretion-forming process. Pieces of the shark Cobelodus (jaw, at least) have been found in the concretions, but who knows how many others?

[Missourian]

Another fin?

 

 

I'm not sure if this is a fin or a bone/element with some interesting structure:

 

 

I didn't make out any denticles in the smooth area.

[Missourian]

Partial shark mandible:

 

[Roz]

That mandible is very nice!

On the image before this one, I just can't tell..

The fins I have found are much thinner but maybe it's just a different fish/shark

than I find..

[Missourian]

Actinopterygian fish brain cast
Lawrenciella sp. (schaefferi?)

 

 

 

 

I pulled these from my micro thread. I'll bring a couple more specimens under the microscope when I can get to them.

[Roz]

So much better under the scope!! I can see more details.. Beautiful fish head!

[Missourian]

On 6/26/2013 at 6:29 PM, Roz said:

So much better under the scope!! I can see more details.. Beautiful fish head!

 

Thanks. Most striking to me are the filled sinuses that resemble pebbles.

[Roz]

Thanks. Most striking to me are the filled sinuses that resemble pebbles.

Oh yes! I love seeing that feature. I learned something.. A few heads

I have found have that but I didn't know what that was!

[Missourian]

Actinopterygian fish brain cast
Lawrenciella sp. (schaefferi?)

 

Specimen #2:

 

 

Note the area marked with a green arrow. Up close, some interesting detail can be seen:

 

[Missourian]

Actinopterygian fish brain cast
Lawrenciella sp. (schaefferi?)

 

Specimen #2 again. Note the arrows:

 

 

Specimen #2 detail (red arrow):

 

 

Specimen #2 bone structure (blue arrow):

 

[Roz]

I love seeing those!

Do you know what those are called? To the right of the xxxxx's?

I may have solved some of my mystery bones because several look

just like those..

[Missourian]

On 6/28/2013 at 10:36 AM, Roz said:

I love seeing those!

Do you know what those are called? To the right of the xxxxx's?

I may have solved some of my mystery bones because several look

just like those..

post-6808-0-85424500-1372400258_thumb-001.jpg

 

I'm not sure. They are labeled in that Lawrenciella PDF, but I haven't yet read the whole paper to find a description in the text. They seem to be part of a mold left over after some thin bone had stripped away (and is still present in spots in the specimen). They could be pathways and openings for nerves and vessels.

[Roz]

I'm not sure. They are labeled in that Lawrenciella PDF, but I haven't yet read the whole paper to find a description in the text. They seem to be part of a mold left over after some thin bone had stripped away (and is still present in spots in the specimen). They could be pathways and openings for nerves and vessels.

Ok, I need to review that pdf again..

[Missourian]

On 6/28/2013 at 3:07 PM, Roz said:

Ok, I need to review that pdf again..

 

Me too, but when I try to read it, I get bogged down in the anatomical jargon....

[Plantguy]

Actinopterygian fish brain cast

Lawrenciella sp. (schaefferi?)

Specimen #2 again. Note the arrows:

7748-Muncie-Lawrenciella-3b.jpg

Specimen #2 detail (red arrow):

7821-Muncie-Lawrenciella-2-ventral.jpg

Missourian, Wow, is that all soft tissue preservation where I put some more red arrows on your photos...are those vein like structures actually arteries/veins too? Looks like an awful lot of cool stuff going on it that little concretion!

Regards, Chris

[Missourian]

On 6/28/2013 at 9:28 PM, Plantguy said:

are those vein like structures actually arteries/veins too?

 

I had just noticed those too. I believe they are blood vessels -- or at least the canals that contained them. I plan to take a closer look under the scope tonight.

[Missourian]

As promised, close-up of possible blood vessel canals....

 

 

[Missourian]

Actinopterygian fish brain cast
Lawrenciella sp. (schaefferi?)

 

Specimen #3:

 

[Missourian]

For reference, a reconstruction of an Upper Carboniferous actinopterygiian similar to Lawrenciella:

 

 

The Lawrenciella crania, as preserved in the concretions, would lie within the outer skull bones shown.

Also, I've noticed that the mandible resembles the one that I'd posted above.

[Missourian]

Actinopterygian fish brain cast
Lawrenciella sp. (schaefferi?)

 

Specimen #4:

 

 

Up close:

 

 

Other side of specimen #4, showing top of cranium:

 

 

Up close:

 

[Plantguy]

Actinopterygian fish brain cast

Lawrenciella sp. (schaefferi?)

Specimen #4:

7846-Muncie-Lawrenciella-4-bottom.jpg

Up close:

7769-Muncie-Lawrenciella-5-close.jpg

Other side of specimen #4, showing top of cranium:

7840-Muncie-Lawrenciella-4-top.jpg

Up close:

7765-Muncie-Lawrenciella-4-close.jpg

Hi Missourian thanks for the closeups of the vessles and other structures. Holy smokes! So how many concretions do you have to go thru on average to find the good ones like these? Are these freeze/thaw finds or are you doing the light tap on the side method to split em?

I saw the Phyllocarid types, did I miss any Euproops looking crustaceans yet? Awesome stuff man! Regards, Chris

[Roz]

I am also enjoying these great closeups! Keep them coming..

[Missourian]

On 6/30/2013 at 8:32 AM, Plantguy said:

Hi Missourian thanks for the closeups of the vessles and other structures.

(1) Holy smokes! So how many concretions do you have to go thru on average to find the good ones like these?

(2) Are these freeze/thaw finds or are you doing the light tap on the side method to split em?

(3) I saw the Phyllocarid types, did I miss any Euproops looking crustaceans yet?

 

1. It's hard to say how many. We've gone through so many over the years. I'd say roughly a thousand concretions to find a Lawrenciella (though Roz may have had better luck in Texas). Even more are needed to find a complete shrimp.

 

2. We've always used a hammer. It starts with taps, then whacks, then smash. We hadn't tried freeze-thaw (actually, we hadn't thought of it, and early on, I'm not sure what my parents would have thought of a couple hundred nodules in the freezer. ). Hammering is rough, but I'm not sure how freeze-thaw would work on complexly structured fossils like Lawrenciella and ammonoids. I'm afraid they would fall to pieces. Still, it may be worthwhile to prep certain pieces like specimen #4 above by freeze-thawing away some of the nodule matrix.

 

3. There are most likely no Euproops or any other freshwater types. The preserved fossils in the Muncie Creek seem to be pelagic animals that lived closer to the surface of the open sea and then sank to the anoxic bottom after death.