Knightia Alta ....?

[Gareth_]

I'm fairly sure this a Knighia alta but as always, it's best to run it past the experts

I don't have a find location - some places I buy fossils from are terrible at provenance, it's just stock to sell to them. 

Looking at the side of the slab, there are many other fossils within too - I don't want to destroy to fish to find out what they are   

[Kane]

@Fossildude19

[RJB]

Diplomystus dentatus

 

RB

[Fossildude19]

I agree with Ron.

The deep body, thickened post cranial bones, and the deeply forked tail mark it as a Diplomystus dentatus.

[Randyw]

Yep. It’s a diplomystus. Even though it’s badly damaged you can see the remains of the long anal fin too

[Gareth_]

@RJB @Fossildude19  @Randyw Thank you! 
The thickened post cranial bones - do you mean between the skull and the dorsal fin? Looking at other specimens online, that seems to be a notable difference between Diplomystus and Knightia. Or the skeleton is generally more robust than a Knightia? 

This would be Green River Formation I'm guessing?

There is also an odd blob on the caudal fin, could this be a scale from a larger fish? Or is it just part of the Diplomystus?

It's fascinating looking at the cut edge of the matrix, the amount of layers which make it up is amazing! 

 

Sorry about the questions.... getting an ID is one thing but understanding how you came to that ID is far more interesting

[Top Trilo]

I agree the part I look for is the anal fin as Randy pointed out. I'll let Tim point out the finer details but for me the anal fin is easiest, its just not always preserved.

 

 

Notice how on the Diplo the anal fin stretches much farther than on a Knightia.

 

And for your other questions, yes its from the GRF of Wyoming and I bet the scale on the tail of the Diplomystus is from a different fish, its much larger than what I'd expect the Diplo to have.

[Randyw]

2 hours ago, Gareth_ said:

It's fascinating looking at the cut edge of the matrix, the amount of layers which make it up is amazing! 

It gets more interesting when you realize these black marks are probably cross sections of other fish or fish poop…

[jpc]

Gareth... if you take this to your local hospital radiography dept and put on your best puppy dog eyes and charm them, they may be willing to take an x ray of it and see what sort of fish (or half fish) you have visible on the edge.  Tell them they get to turn their machines up to full blast... they love doing this because they can't do it on humans.

[Fossildude19]

On 7/5/2022 at 10:23 AM, Gareth_ said:

The thickened post cranial bones - do you mean between the skull and the dorsal fin?

 

 

Yes.

 

[Gareth_]

On 7/6/2022 at 6:18 AM, jpc said:

Gareth... if you take this to your local hospital radiography dept and put on your best puppy dog eyes and charm them, they may be willing to take an x ray of it and see what sort of fish (or half fish) you have visible on the edge.  Tell them they get to turn their machines up to full blast... they love doing this because they can't do it on humans.

I wish that was an option.... with our government and part of our country still in hysterics over a certain virus (and massive staff shortages in healthcare), they wouldn't take kindly to a bit of fun I imagine. Fantastic idea though, I'd love to see what's inside without destroying the fish

 

Thank to all that contributed, I have learned a lot and it is appreciated!

[FranzBernhard]

On 7/5/2022 at 8:18 PM, jpc said:

Tell them they get to turn their machines up to full blast... they love doing this because they can't do it on humans.

This gave me a really hard and long laugh!!

Franz Bernhard