Coelacanth Prep

[Ptychodus04]

@Jeffrey P has issued quite a challenge with a request for preparation of a small coelacanth. This little guy appears to only be missing the tip of the head. Unfortunately, the rest is under a thin layer of diamond hard shale!

 

Here's a pic of the specimen as it arrived. Where's Waldo? Only parts of the skull are exposed with a hint of the caudal fin under the matrix.

 

 

 

 

 

Here it is after 4 hours of prep. This guy is a textbook example of sticky. I'm switching between 3 tools to prep this. I start by removing about 1/2mm of matrix with the Aro. This is kind of like doing dental work with a jackhammer but if you're careful, it will get you down to the later just above the bone pretty quickly. Then I switch to the Micro Jack. The problem with the scribes is that the matrix turns white when you scribe it... and the bones are white! I scribe away for about 10 minutes with eagle eyes out for any hint of bones (this uncovers an area about 5mmx10mm) and then hit it with abrasive to knock off the scribe marks so I can see the bones against the matrix.

 

 

[aerogrower]

Crazy man could not even see it in first pic! Cant wait to se this finished.  

[StevenJD]

[Fossildude19]

@aerogrower

 

If I am not mistaken, this is the one being prepped:

 

 

From JeffreyP's Triassic Gallery. 

 

These fish can be extremely hard to see, unless held at the correct angle in good lighting. 

 

@Ptychodus04

Looks great so far, Kris! 

Good luck with the rest of the prepping.   

Not to tell you your job (at all!) , but be sure to keep an eye out for the supplemental caudal fin, if it is there. ( Many times they are not. )

They can be hard to spot, and easy to accidentally remove. 

 

 

Previous picture from HERE.

 

 

 

 

 

 

 

 

 

[aerogrower]

6 minutes ago, Fossildude19 said:

If I am not mistaken, this is the one being prepped:

That's better lol. Even I can see that! Great find.

[RJB]

Very interesting thread!  I most certainly wouldnt want to prep that unless it was mine.  A real tuff prep but a really cool fossil.   its a good thing your doing this fish now Kris, it will make my fish seem super easy.   Cant wait to watch this unfold.  I hope you will post pics of the on going process.

 

Ron

[ynot]

[Ptychodus04]

@Fossildude19 no worries, I have no issues taking advice from people who know a species better than I. That is the fish I'm working on. My photography lighting isn't the best. 

 

I believe there is a hint of the supplemental fin when viewing under the microscope. I circled the area with a pencil last night so I don't lose it. It is so small and faint under the matrix that you can't even see it with the naked eye.

 

@RJB I'm always up for a challenge, especially when I'm getting paid for it! I'll be the judge of your fish... If you ever get around to sending it to me! You've been so busy with ammonites that I don't blame you one bit!

[Ptychodus04]

Here's the little guy after 4 more hours for a total of 8 hours to date. The scribe/abrasive/scribe cycle is working well. I have noticed the slightest lamination along the bedding plane so this has helped to speed the process. I am able to remove more matrix between abrasive sessions without fear of removing bones. It's still a painfully slow process.

[RJB]

Lookin good.  May I ask what media you are using? 

 

RB

[Ptychodus04]

56 minutes ago, RJB said:

Lookin good.  May I ask what media you are using? 

 

RB

 

Thanks. I'm using soda. The main matrix removal is with the Micro Jack and the abrasive only removes the scratches from the matrix so I can see the white bones.

 

This matrix is so hard that the scribe squeals when the stylus touches it.

[RJB]

If the matrix is that hard, im suprized that soda is doing the job!!!???  sound like its some real slow going stuff.  But dang!  What a super nice fish to be working on!!!

 

RB

[Ptychodus04]

1 hour ago, RJB said:

If the matrix is that hard, im suprized that soda is doing the job!!!???  sound like its some real slow going stuff.  But dang!  What a super nice fish to be working on!!!

 

RB

 

The soda only removes the finest scratches. It barely does anything at all. It only brings the matrix back to its original color so I can see the bones again.

[RJB]

Ok, I get it now.  Goooooooooo Kris goooooooooo!!!

 

RB

[Ptychodus04]

3 more hours in for a total of 11. I'm now trying to find the elusive lobed fins on this guy. 

 

[Macrophyseter]

So far, so good. Good luck on the lobed fins!

[RJB]

Ok, im tryin to figure whats going on here?  Are the bones white in color? 

 

RB

[Ptychodus04]

3 hours ago, RJB said:

Ok, im tryin to figure whats going on here?  Are the bones white in color? 

 

RB

 

Yes sir. That's what makes it so hard to prep when the scribe turns the dark matrix light.

[Ptychodus04]

12 hours 15 minutes total and the coelacanth is done. Unfortunately, several of the fins were not preserved. This isn't very surprising given the disarticulation of the bones. The one dorsal fin preserved is twisted around on itself. There appears to be a bit of the second dorsal squished against the caudal fin.

 

This fish really put my prep skills to the test. It was prepared 100% under the microscope with the Micro Jack and abrasive. It has microscopic bones and an extremely hard and sticky matrix. Not a good combination!!

[Kane]

Well done! Chapeau, indeed, for all the good work you did bringing out this fish under pretty stubborn conditions. 

[Fossildude19]

Kris, 

Great job - looks very cool.  

[Ptychodus04]

4 hours ago, Kane said:

Well done! Chapeau, indeed, for all the good work you did bringing out this fish under pretty stubborn conditions. 

Thanks. You sent me to the dictionary with chapeau.  Now I have a new word to use!

 

4 hours ago, Fossildude19 said:

Kris, 

Great job - looks very cool.  

 

Thanks. Your opinion ranks pretty high with these things as I understand you are quite the expert on these fish.

[ynot]

That looks really nice, good job!

[Doctor Mud]

Fantastic work!

 

i could feel a bead of sweat starting to form on my brow with the thought of working on white bones in a rock that turns white when scribed 

[Fossildude19]

8 hours ago, Ptychodus04 said:

 

Thanks. Your opinion ranks pretty high with these things as I understand you are quite the expert on these fish.

I wouldn't go that far, ... I'm a bit knowledgeable, maybe.

I'm more familiar with the Jurassic fish fossils of my local area.

But thanks for the kind remark.