White River Prep - Rodent

[ParkerPaleo]

I've been in the lab this fall/winter but preparation has taken a back seat to the plastics/replicas operations.  As things start to wind down with plastics around this time of year, I'm embarking on my next prep project.  This specimen is from the same Wyoming locality as the Herpetotherium I posted about recently but was found many years ago(~15?).  It appears to just be an upper skull of a small rodent but there is some hope for lowers.  I pulled this piece out of its field packaging in April but just now starting preparation in earnest.  So far, all I've done is rough prep around the boundary to remove the bulk matrix surrounding it.  It was attached to a larger block but there is no evidence of any additional bone fragments in the other block.  The bulk removal was done with my trusty ARO but all prep going forward will be done under magnification with a Paleotool's Microjack-3 or pin vices. Identification will take a while but we'll talk about the process as I get the specimen uncovered.  If I had to guess at this point, I suspect it to be Paradjidaumo.  Time will tell if I'm correct.

[Randyw]

Cool! Please Keep us updated!

if i can’t find any white river stuff to prep at least i can live vicariously watching your preps!

Edited December 3, 2021 by Randyw

[ParkerPaleo]

For tonight's hour of labor, I began by working on the right 'face'.  I exposed more of the zygomatic, an incisor and the front two cheek teeth.  For something so small, it was certainly difficult to picture.  Rodent skulls have complex geometry.  I used the Microjack-3 exclusively.  I will coat the surface with some Paleobond Penetrant in the morning when I am rested.  I use 'micropipettes' to apply this consolidant in a controlled fashion.  We only want glue to hold the specimen together, not bury it in glue so thick we can't see the detail.  I did not see any evidence of the jaws, there remains a slight c hance but experience tells me they are missing.  I will continue to look for them.

[ClearLake]

Very interesting. I am not at all familiar with prepping White River material, but always amazed at the cool specimens that come out of there.  How hard is that matrix?  Does it separate from the bone easily?  The color difference between the bone and matrix is very nice and I assume helps in the prep process. Thanks for showing your process. 

[RJB]

5 hours ago, ParkerPaleo said:

I use 'micropipettes' to apply this consolidant in a controlled fashion.

Im assuming that these 'micropipettes' are smaller than the ones I use?   I use these pipe needle tubes with a 2 oz bottle of ciano.

 

RB

[ParkerPaleo]

3 hours ago, RJB said:

Im assuming that these 'micropipettes' are smaller than the ones I use?   I use these pipe needle tubes with a 2 oz bottle of ciano.

 

RB

Yes, they are the tiny tubes that come with the cyano bottles from Paleobond.  I'm not sure what the proper term is for them.

[ParkerPaleo]

8 hours ago, ClearLake said:

Very interesting. I am not at all familiar with prepping White River material, but always amazed at the cool specimens that come out of there.  How hard is that matrix?  Does it separate from the bone easily?  The color difference between the bone and matrix is very nice and I assume helps in the prep process. Thanks for showing your process. 

The matrix is very consolidated and hard enough that mechanical prep is needed.  We suspect this locality is a burrow community which results in many small specimen not seen elsewhere in the White River.  That being said, it's not so hard either, it is still an overbank mud deposit.  We use dolomite/sodium bi-carbonate for air abrasives on it to give you an idea of relative hardness.

[fossilhunter21]

Awesome! White River formation fossils are so cool!

 

Looking very good so far! 

 

Good luck, and looking foward to seeing your progress.

 

-@fossilhunter21 

 

[ParkerPaleo]

A little progress this afternoon and a definitive identification.  I exposed a row of cheek teeth, did some light reading and concluded that my guess of Paradjidaumo trilophus was correct.  Hopefully I've get some time this weekend to continue preparation.  I really need to ask Santa for a camera that attaches to my scope.

 

 

[jpc]

Nice specimen, PP.  Nice work.  Do you do the final details with the air abrasive.  I use mine at 5 psi under the microscope on the teeth to clean them up nicely on these litte rodents.  Have you ever tried the scratch technique for applying microdots of glue?  You can do even smaller amounts of glue if you put a small drop on a piece of paperboard and scratch it with a very sharp dental pick (or whatever) and you get a wee bit of glue on some fibers.  

[ParkerPaleo]

I was going to consider some light abrasion at the end.  I finally got my MV-1 setup here again.  I'll see how far I get with mechanical first.  I did try the glue techniques, that was a useful tip on that last marsupial I did.  I need to keep trying that so it becomes part of my routine/standard bag of tricks.

[jpc]

keep this in mind... some paperboards are better than others.  Corrugated cardboard is not good.  

 

[ParkerPaleo]

I've been using old stacks of business cards from companies I no longer work for.  Generally pretty decent paper.

[ParkerPaleo]

Yesterday I decided to clear off the other side of the rostrum.

 

There's a bit of glue in these pics on top of some things but it'll be cleared up before we are done.  The tip of the nose had been glued in the field and it will take a bit to get clean but I'm going to rough it completely out before returning to do final glue removal and proper consolidation.  Next up on the agenda is to work the cranium out.

 

[Randyw]

Looking great so far!

[ParkerPaleo]

I started working on the braincase and figured out there is less of it than expected.  The back of the skull (occipital, etc) have been removed and the auditory bullae are missing as well.  This is not uncommon though.  I'm thinking it means this specimen was someone's midnight snack, I'd like to imagine it was a Paleogale but any of the small carnivorans would be capable.  I'm now thinking about how exactly I'd like to finalize this prep.  I was thinking of leaving the small block of matrix on the rear, remove the matrix on the palate and have it stand sideways to display the top of the skull on one side and the teeth on the other.  And maybe put it in a square baseball display case for protection.

Edited December 6, 2021 by ParkerPaleo

[jpc]

from the rodent skulls I have seen out in the wilds,I think the back of the skull is the first part to fall apart, predator/scavenger or not.  Oh, and don't forget the birds of prey that lived during the White River time.  Very few actual fossils but they were there.  (The Smithsonian has a block with 7 small owl skeletons in it)!!!!  

[ParkerPaleo]

I still want it to be from a Paleogale.  My favorite little predator

[jpc]

Paleogale is by far the coolest little mammalian predator in the White River.  I would love to find one. 

 

[ParkerPaleo]

I was under the weather a bit the last week and did not do much but yesterday I found some time and was feeling better.

 

As things are progressing, I've been thinking about how to display this.  I am planning to leave the matrix block attached to the cranium (since it will be incomplete anyway) and have it sit on a tiny pedestal inside a 'baseball' display case.

 

At any rate, I started removing matrix on the palate.  When I removed the bit in front of the incisors, I must have jarred a piece loose because the tip of one fell out and onto my desk.  It took a good deal of patience to find it and get it back in place as it was about a half millimeter in size.  In the end, I had to put a tiny bit of bee's wax on the end of a carbide needle so I could orient and place the tip back on the specimen.  My hands and nerves were shot after that but it is all back together.  Hopefully I should be finished in another session or two.

 

 

[jpc]

beeswax... good idea.

 

[ParkerPaleo]

That's actually a very old trick.  Way before I knew of the Oligocene burrow communities, I collected ant hills.  We mounted those specimen in small glass vials with a cork and a pin with wax on the head.  I'm not sure how old that technique is but it's long before my time.  I just knew the tip of that incisor was something I wouldn't be able to manipulate with my hands and I didn't want to risk shattering it with tweezers.

[Randyw]

It’s lucky you were even able to find it with it being that small! Thanks for the beeswax tip too I’ll have to remember that for my future preps!

[ParkerPaleo]

It hadn't gone far.  It fell out when I rotated the specimen.  It would have been alot different if I had an air stream running past it during abrasion or something.  But it was still not easy to see.  I like to keep a little consolidant on the specimen as I prep to keep things like this from happening but as it gets applied and removed continuously, these things happen.

[jpc]

I usually use a wetted (in my mouth) paintbrush of rather small size.  I have also used a piece of scotch tape folded into a little triangle with the sticky side out.  You can use the point of the triangle to pick up and handle itty bitty bits like tooth cusps.