Requesting help with my first vertebrate prep job (It's a big one!)

[DokDeino]

16 hours ago, jpc said:

There are at least 14 genera of sauropods in the Morrison.  I think it is a bit premature to ID it with all this plaster.  Do you have any reason to believe they are form the same animal.  A lot of Morrison sites are mixes of many bones form different animals.  I do agree, however on them being femur and humerus.  I assume the part in red is sticking out towards the camera a bit.  Again, call me if you want to talk about a strategy for these things.    I have a lot to offer, and I would hate to see them ruined..  

That's fair, an ID should wait. 

 

Well, we do know a couple things about the specimens:

 

1 - They were found in association, or at least nearby one another

2 - The size and shape appear to be consistent with Sauropod remains for both pieces. (Femur is about 1.6 m, humerus is around 0.7 m)

 

It is possible they are from different specimens, but we cannot be sure at present. 

 

Also, a quick amendment to my earlier posts: My advisor is not wanting to use epoxy, that was a misunderstanding on my part. He wants to use butvar to coat and help consolidate the surface of the bone as it is uncovered. 

[hadrosauridae]

As others have said already, proceed SLOWLY!  I recommend starting with the small jacket first.  You see the bone-shaped side of the jacket? Don't start there.  Flip it over and cut the jacket on the other side.  The side facing up in the picture in the the bone sitting on the pedestal of matrix they cut around it.  You want to make your cut where there is matrix.  Take your time and try not to cut into the matrix, just for practice for when you open the femur.  You wont hurt anything to hit the matrix with the blade or saw, but you dont know how thick that jacket is or how hard it is to cut through.  It will be a good learning time.

 

Now, whoever did that femur did the preparator dirty.  It looks like it was field prepped and then jacketed which means that you probably dont have a matrix pedestal side to cut into.  Careful, careful, careful. 

 

At this point in time, don't even say the word "epoxy".  That is a permanent item that can never be truly, completely removed.  You need to learn about making your own glues and consolidants of Butvar or Paraloid.  Epoxy is typically only used in the last steps when you are doing reconstruction of pieces that no longer join cleanly and have large gaps to bridge. 

 

Good luck, I hope to see more pictures as you work on these pieces!

[DokDeino]

16 hours ago, hadrosauridae said:

As others have said already, proceed SLOWLY!  I recommend starting with the small jacket first.  You see the bone-shaped side of the jacket? Don't start there.  Flip it over and cut the jacket on the other side.  The side facing up in the picture in the the bone sitting on the pedestal of matrix they cut around it.  You want to make your cut where there is matrix.  Take your time and try not to cut into the matrix, just for practice for when you open the femur.  You wont hurt anything to hit the matrix with the blade or saw, but you dont know how thick that jacket is or how hard it is to cut through.  It will be a good learning time.

I'll be taking it nice and slow, don't worry. I plan to inch along the whole way.

 

The smaller jacket is the first target for sure, I want plenty of experience working with the matrix before even thinking of removing it from the fossil directly. 

 

16 hours ago, hadrosauridae said:

Now, whoever did that femur did the preparator dirty.  It looks like it was field prepped and then jacketed which means that you probably dont have a matrix pedestal side to cut into.  Careful, careful, careful. 

As far as we know, that's what happened. We have a photo of the femur in-situ with the discoverers somewhere in the university library, I'm going to try and find it if I can. There also seems to be a bit of matrix (or at least bunched up plaster) on the backside of the femur, where the wood beam lies. That's probably where I'll start. 

 

16 hours ago, hadrosauridae said:

At this point in time, don't even say the word "epoxy".  That is a permanent item that can never be truly, completely removed.  You need to learn about making your own glues and consolidants of Butvar or Paraloid.  Epoxy is typically only used in the last steps when you are doing reconstruction of pieces that no longer join cleanly and have large gaps to bridge. 

Aye, this was a misunderstanding on my part. When I wrote my original post, I thought that epoxy was a catch-all term for adhesives and consolidants...turns out that's not correct. We are planning on using Butvar to consolidate the fossils. 

 

16 hours ago, hadrosauridae said:

Good luck, I hope to see more pictures as you work on these pieces!

Gratzi, I'll keep this post updated as I go!

[DokDeino]

Major Update 1:

 

Hello, everybody! It's been a hot minute! I got busier during the holidays than I anticipated, and I had to wait for bureaucracy to finish, so opening the jackets had to wait until this week. 

 

That said, we've opened one of them! The humerus, to be specific. 

 

Day 1

To begin with, my supervising professor and I put the jacket humerus-side-down on our worktable, using a thick bed of foam to stabilize it.  (Photo of the humerus before moving it)

Then we alternated using a handheld circular saw to cut away the plaster attaching the wood beam to the specimen, while the other person used a vacuum to catch the dust. It took a bit, but we eventually took it off, to reveal that we were left with a thick layer of plaster between the outside of the jacket and the rock within. I spent the next few hours using the saw to cut away plaster strip by strip. Fortunately, it was easy to separate it from the rock. The rock is a yellow siltstone, and is very friable. 

 

I should also mention that we do have photos of the specimens in-situ, and we knew there would be nothing in danger of being harmed on this specific side of the specimen. That probably shaved a couple hours off the prep time. 

 

(Jacket at the end of Day 1. Vacuum got clogged near the end, so everything got coated in dust...including me.)

(Uncovered area outlined in red)

 

Day 2

Today, I went in and spent a solid 5 hours removing the top of the jacket. It was slow, dusty work, but I fixed the vacuum! So at least it wasn't as dusty as Day 1. 

(Fresh, exposed rock. Wet patch near the bottom right, my professor wanted to demonstrate the solubility of the matrix. It basically melts as soon as it gets wet.)

 

It wasn't long after I started digging through the rock (again, very easy to pick apart by hand, without damaging the stone), that I discovered a chunk of isolated bone, lying about 2 cm under the original surface. The bone was already broken in two, and I carefully pulled it out of the rock, painted the pieces with butvar, and bagged them. 

(Apologies for the blurry image, they are very small (<7mm per side, each) and it was hard to get my camera to focus on them.)

 

I wasn't able to get a good image of them, but here is a rough drawing of the cross-section structure. 

I should mention that the cortical bone has straight lines tracing away from the middle, and concentric rings around the middle. Not sure what it is, honestly. No signs of enamel.

 

As I continued, there were lots of other tiny bits of bone, most of them hard to examine with the naked eye. So I bagged and labelled them for later examination. Some were embedded in rock, for them I stripped away as much rock as I could without affecting the bone itself. I also found what appear to be small plant fossils, though I was not certain. Those were also bagged for later analysis.

 

Jacket at the end of Day 2

 

In total, I removed the top few centimeters of rock, extracting about a dozen fossil samples. We're in for a blizzard tomorrow, so I probably won't go in to do lab work, but who knows. If I do, I'll post another update! 

 

I want to once again give a massive thank-you to the kind members of this forum, who gave me lots of useful advice. 

 

Oh, and I have some new information about the specimens I can share! 

 

Both were found in upper Morrison strata, unknown if they were in association. Most likely location is a Morrison exposure near Shell, Wyoming. Approximately 2-3 km west of the Howe Quarry. They appear to be from a fluvial deposit.

 

In addition, over the holidays I managed to come in and take measurements of both specimens (taking into account any shenanigans from awkward plastering), and I have come up with tentative IDs for both of them (I had a lot of time where I couldn't do anything). Results were re-run several times with diagnostic feature measurements increased and decreased by up to 10%. Came back with the same conclusions regardless of what I did to the numbers, without altering the dimensions of the visible fossils beyond reasonable levels. Based on several papers on Morrison Sauropod Morphometrics, both specimens appear to be from Camarasaurus. However, it is very unlikely that they come from the same individual. The morphometrics for the humerus chart it as a large juvenile, while the femur matches the morphometrics for an adult. For the femur in particular, there are visible characteristics that preclude it from being a diplodocid, and strongly suggest it is a macronarian, at least going by the papers I read. 

 

Possible species based on geographic distribution are C. lentus and C. lewisi, but I doubt I could get the ID down to a species designation. Not unless there are some super-specific criteria that distinguish them. I'm good just sticking with Camarasaurus sp., barring new evidence. 

 

Quantitative Morphometrics of Common Morrison Sauropods: https://www.jstor.org/stable/4096900

Qualitative Descriptions of Common Morrison Sauropod Limb Bones: https://repository.lsu.edu/gradschool_dissertations/2677 

Page 160 of this paper has a chart comparing Camarasaurus femur and humerus lengths at different ages and sizes:  https://www.academia.edu/57845546/Anatomy_of_Camarasaurus_lentus_Dinosauria_Sauropoda_from_the_Morrison_Formation_Late_Jurassic_Thermopolis_central_Wyoming_with_determination_and_ 

 

If anyone would like to give it a shot themselves, I'd be happy to share my measurements! 

 

Have a good one, folks!

 

-Dok

[DokDeino]

Greetings, all. I've made a ton of progress on my preparation of the juvenile sauropod humerus, and I wanted to share! I've got some good news, and some bad news.

Good news: I've uncovered about as much as I can with the current tools at my disposal. The specimen has also been reinforced with butvar and plastic cement, so it's much less prone to falling apart.

Bad news: It appears that a concretion formed around the upper end of the humerus after burial (the right side). Aaaand some of the matrix has become fused with the fossil. Which is...not fantastic. It's gonna take a few hours with some tiny drills to cut through the chunks of rock on top of the bone, in order to clear them away.

Once that's over, and all of the bone is as reinforced as it can be, the current plan is to cut away excess plaster, support the fossil with a mold, and flip it over to remove the rest of the plaster.

On the whole, the humerus is in much better shape than my professor and I feared. It has some postmortem distortion (the lower end appears to have been crushed into the midshaft post-burial), and there are plant roots cutting through the bone, but it seems like next year my university is going to have a decent dinosaur bone for the teaching collection! Now we just have to hope the femur is in good shape.... 

Overhead View of the Specimen

Zoom-in on Distal End, featuring crushed portion of the midshaft

Zoom-in of the Proximal end, featuring concretion elements fused with the fossil. There are some chunks that fell off during preparation that will be re-attached after cleaning.

In general, the humerus is in pretty good shape. The overall form of the specimen has survived much better than I expected. Once it's fully reinforced, it should be good to teach with!

Thanks for reading, y'all! Have a good one!

[hadrosauridae]

Sorry I missed your update last month.  Looks like you are really making some good progress, going slow, and obviously learning a lot!  Also sounds like you have a good mentor and and have a solid plan ahead of you.  I cant wait to see the final prep.

 

PS- your text in the last post showed as white letters on a white background on my computer.  I had to highlight it to read.  Not sure if it is a forum glitch, or something you clicked.  was it a copy and paste text block?

[DokDeino]

2 minutes ago, hadrosauridae said:

Sorry I missed your update last month.  Looks like you are really making some good progress, going slow, and obviously learning a lot!  Also sounds like you have a good mentor and and have a solid plan ahead of you.  I cant wait to see the final prep.

 

PS- your text in the last post showed as white letters on a white background on my computer.  I had to highlight it to read.  Not sure if it is a forum glitch, or something you clicked.  was it a copy and paste text block?

Well gratzi! I'd say I'm learning a ton, and I'm super excited to make this fossil look as good as possible. I only hope it's a good reference for future students' work. And who knows, maybe it'll even be research-worthy! 

 

As for the formatting, that's odd. I typed it normally, I hope that doesn't continue in the future. That said, I'll try to make updates a weekly event, since I'm working on this specimen every Thursday and Friday. 

 

I've been incorporating more advice from the forum recently, such as using a razor and utility knife to slice away thin layers of sediment. It's actually very useful, though it lacks in precision. Unfortunately, I probably won't be doing much more until I get a good-quality drill for cleaning, along with a good magnifying lense. 

[jpc]

Hey.. I also missed your January post.  What the heck?  

 

Looks great.  Does the rock right next to the bone also dissolve nicely in water?  If so, you are in luck and this thing could clean up very nicely without special expensive tools. 

 

Drill?  What is your plan for a drill?  I don't see how a drill will help.

 

What are you using for a glue?  Butvar is good for protecting bone but it is a terrible glue.  If you still have my number feel free to call me

[DokDeino]

11 minutes ago, jpc said:

Hey.. I also missed your January post.  What the heck?  

 

Looks great.  Does the rock right next to the bone also dissolve nicely in water?  If so, you are in luck and this thing could clean up very nicely without special expensive tools. 

 

Drill?  What is your plan for a drill?  I don't see how a drill will help.

 

What are you using for a glue?  Butvar is good for protecting bone but it is a terrible glue.  If you still have my number feel free to call me

Heh, my apologies.

All of the matrix appears to dissolve quickly in water. That said, I am afraid the bone will as well, so I want to avoid use of water to loosen the matrix as much as possible. 

As for the drill, we have one coming in the mail that will let me remove millimeter-scale scraps of matrix, smaller than I can achieve with any pick. Just easier to carefully remove matrix from the specimen, and minimize damage to said specimen. 

For glue, we are using a plastic cement suspended in alcohol, that way we can dissolve it later if need be to clean it up. I can't remember the name of it at the moment, my apologies. We are not using butvar as a glue, just as a consolidant. 

[jpc]

Thanks for the info.  I am intrigued by the drill.  What sort of drill is it?  

Sauropod leg bones tend to be very heavy as I am sure you have noticed.  

Have look at this... this is a piece of a poster that may be available online. 

I googled "Amy Davidson paleontology glues" to find it.  Lots of info about glues.  Note that they use Devcon 2 ton epoxy for sauropod leg bones.  

In my lab we are more of a cyanoacrylate lab.

Edited February 4 by jpc

[Alex S.]

Great update that bone looks good! I am also curious about the drill it looks like you have some fun times ahead of you. 

[DokDeino]

On 2/4/2024 at 2:07 AM, jpc said:

Thanks for the info.  I am intrigued by the drill.  What sort of drill is it?  

Sauropod leg bones tend to be very heavy as I am sure you have noticed.  

Have look at this... this is a piece of a poster that may be available online. 

I googled "Amy Davidson paleontology glues" to find it.  Lots of info about glues.  Note that they use Devcon 2 ton epoxy for sauropod leg bones.  

In my lab we are more of a cyanoacrylate lab.

Went back through my communications with my professor, we are using duco cement for now. It's not intended to be permanent, and can be removed with Isopropyl alcohol. I'll ask him what he wants to eventually replace it with. 

 

My professor is handling getting new tools, right now I'm just cleaning up some parts of the specimen to get ready for future work. 

[jpc]

Duco will turn yellow and brittle in a matter of years.  And re-doing everything you are doing with it now will drive you nuts.  Invest in some Paraloid or cyanoacrylate for the sake of the bone and you.