Pennsylvanian unknowns. Fish scales? + gastropod?

[connorp]

Going through last year's finds I found a few things that I don't recognize. All are from Pennsylvanian marine limestone. The first few all appear to be fish material of some kind. I find plenty of chondrichthyan teeth, but none of these look like any teeth I've seen, although they may be partials. Possibly some kind of bony fish scale? All images were taken under a microscope, no scale cube but they all are about 1/2" at the widest point.

 

#1)

 

#2)

[connorp]

#3)

 

And #4 appears to a gastropod. It was on a block of matrix with a tooth that was in a vinegar bath, and I only noticed it after a few hours in the bath. So I'm guessing there's not enough detail for an ID, but was hoping it was possible to narrow it down, maybe even just to family or order. Not very impressive, but it's the only gastropod I've ever found at this site.

 

#4)

[Fossildude19]

@jdp

 

Looks like paleoniscoid skull elements and possible scales. Something like Haplolepis sp possibly? 

Can't help with the gastropod cross section.  

Great finds, in my opinion.   

Thanks for posting these. 

 

EDIT: Have a look at this post.

 

[connorp]

14 hours ago, Fossildude19 said:

@jdp

 

Looks like paleoniscoid skull elements and possible scales. Something like Haplolepis sp possibly? 

Can't help with the gastropod cross section.  

Great finds, in my opinion.   

Thanks for posting these.

That seems likely, not sure where else thick bony elements would come from. Are the holes in the elements anything specific to paleoniscids? They are present in all the specimens I showed, I've also seen similar holes in microfossils from the Pennsylvanian black shales I've searched, like the one below.

[Fossildude19]

5 hours ago, connorp said:

That seems likely, not sure where else thick bony elements would come from. Are the holes in the elements anything specific to paleoniscids? They are present in all the specimens I showed, I've also seen similar holes in microfossils from the Pennsylvanian black shales I've searched, like the one below.

 

Well, the sheen from the black "holey" elements are very indicative of fish scales/bone/skull elements. 

Not sure if the holes are specific to paleoniscoid fish.  It could be that they are artifacts of erosion of thinner parts of the scales/bones. 

Some holes seem to indicate areas of interlocking components.

I know that the ornamentation on paleoniscoid fish can vary greatly. 

 

 

These elements seem more bone like, to me.  

 

 

[jdp]

Yep, most of those are fragments of fish bone. Not really clear to me what type of fish, but haplolepids are overwhelmingly freshwater so it's probably not a haplolepid. 

[jdp]

On 2/15/2020 at 6:05 AM, Fossildude19 said:

 

Well, the sheen from the black "holey" elements are very indicative of fish scales/bone/skull elements. 

Not sure if the holes are specific to paleoniscoid fish.  It could be that they are artifacts of erosion of thinner parts of the scales/bones. 

Some holes seem to indicate areas of interlocking components.

I know that the ornamentation on paleoniscoid fish can vary greatly. 

 

 

These elements seem more bone like, to me.  

 

 

That larger element is a piece of the braincase of an actinopterygian fish, absolutely. The circle looks like a specific type of exposure of the common dorsal aorta you see in a variety of Carboniferous and Permian actinopts, including things like Coccocephalus and Leuderia. There's enough there that it might be diagnosable to a broader taxonomic group. You actually have an expert on Palaeozoic fishes right by you in Mighican; try sending some pics to Matt Friedman at UMich and see what he thinks. This specimen might be scientifically useful, so I'd try getting in touch with him.

[connorp]

1 hour ago, jdp said:

That larger element is a piece of the braincase of an actinopterygian fish, absolutely. The circle looks like a specific type of exposure of the common dorsal aorta you see in a variety of Carboniferous and Permian actinopts, including things like Coccocephalus and Leuderia. There's enough there that it might be diagnosable to a broader taxonomic group. You actually have an expert on Palaeozoic fishes right by you in Mighican; try sending some pics to Matt Friedman at UMich and see what he thinks. This specimen might be scientifically useful, so I'd try getting in touch with him.

I have a meeting in his department Thursday, I'll try to see if he's available then. Thanks!