Are these scale imprints?

[AvidArchRival]

Hi all, I would like to know if these are scale imprints.

 

Initially I thought they are scales, but after examination under a macro lens, some of the lines lead from the central vertebrate to the dorsal edge, resembling neural spines and are therefore not scales.

 

The specimen is a Knightia, about 3 inches in length. 

 

Thanks for any information.

[jpc]

These are not scale imprints, but actual fossilized scales.  Pretty common on Green River fish like Knightia.  

[FossilDudeCO]

yup, what JPC said.

The Green River Formation fish preserve nearly all of the fish on good specimens.

On a few of them you can even see the detail in each scale like on some large Phareodus specimens.

 

Check out this post, the lone scale is a very nice Phareodus.

 

 

[Rockwood]

While I agree that the scales of Green River fish are well preserved, I sense some confusion here. Surely a single scale would not reach from the vertebral column to the dorsal edge. Would it ?

[oilshale]

3 hours ago, Rockwood said:

While I agree that the scales of Green River fish are well preserved, I sense some confusion here. Surely a single scale would not reach from the vertebral column to the dorsal edge. Would it ?

Ribs and scales are just superimposed: The lines from the spine (vertebral column) to the dorsal edge are the ribs - the small trapezoid structures you can see all over are the scales.

 

 

In some species, scales can get really large - this is a Habroichthys from Switzerland.

[oilshale]

This is another Knightia (from Ludwigia's gallery).

Scales and ribs are better to see when the fish already started to rot a little bit.

[digit]

I'm wondering if there has been some confusion on understanding the original question. In the original photograph the preserved scales are quite apparent and the lines separating the scales can easily bee seen. Virtually all of the backbone (vertebrae) are missing in this specimen as are the neural spines radiating out from these vertebrae. This is from the split-fish layer and the bones may still be on the other half of this fish fossil. If the question (as I understand it) is about the tiny elongated troughs that curve to the right in the photo, these appear to be impressions where the neural spines would have been (they should be present in the matching half if that was available). The image directly above from Ludwigia's gallery more clearly shows these bones.

 

Hope this provides clarity on the original query.

 

 

Cheers.

 

-Ken

[AvidArchRival]

Thanks for the replies and input, everyone. I guess it's settled then. Those are scales with, as oilshale said, ribs or neural spines superimposed.

 

@digit, if i understand you correctly, the vertebrae column and neural spines were lifted off with the other half of the rock. Is it instead possible that the vertebrae column and neural spines are under the scales here? 

[digit]

Looks to me that the bones ended up on the other half of this specimen. Just the impressions and scales left on this side.

 

 

Cheers.

 

-Ken

[abyssunder]

That's what I'm seeing, too. The fish is in a longitudinal split so that almost all of the ribs are in the counterpart of the matrix, the scales and one rib (the eighth from left visible on the upper part of the fish) are in your matrix.