My Dyrosaurus prep/mount project diary

[Aurelius]

I posted recently asking for opinions on a partial Moroccan Dyrosaurus skull and jaws that I've had for a while, waiting for me to do something with it. The feedback I had encouraged me to start work on it, so I'm going to document my progress here.

 

I seem to have most of the skull and upper jaws, though it is in a very fragmentary state. The bone pieces are very delicate and most are still covered in matrix. 

 

 

I plan to clean and consolidate all of the bones, and then mount them in 3D. Whether I will do this in the traditional way, or with the help of my 3D printer, I am as yet undecided.

 

This summarises my position as of now:

 

• I have lots of bones, and don't know what they are.
• I have no idea what I'm doing.
• I have never done anything like this before.

 

I'm sure a lot of people would tell me to leave it alone and give it to a professional to do, but firstly I don't have that kind of money and secondly I am keen to learn. If anybody has any tips at any point, those would be greatly appreciated. If you'd rather tell me something in confidence, please send me a message and I will keep the information to myself. Anything I discover on my own I will post here for the benefit of anybody else stupid enough to attempt this.

I have cleaned a few of the bones so far, and after some initial hiccups, it's now going well.

 

My method is to dab water onto the matrix, which quickly soaks it up. I continue until the matrix is sodden, at which point is usually comes away fairly easily using a dental pick and a scalpel. As I go, I consolidate the outside of the bones using small quantities of superglue to prevent breaks, and help maintain the basic stability if anything does break. When I'm finished, I have the option of using solvents to remove a bit of the excess glue, but whilst I'm working on it I want to know it's not going to fall to bits.

 

 

Once I have removed the bulk of the matrix, I use a damp brush to remove any residual bits, and then a dry brush to remove small particles. Then I repeat as necessary.

 

Here's my progress so far - a handful of cleaned and partially cleaned bones. My aim isn't to get them all pristine and white, just to remove the matrix to a point where all of the shapes and details can be seen. I don't mind a little bit of Moroccan sand here and there. 

 

Anyway, that's how far I've gotten. I will post occasional progress updates as I progress! I will also post better images in future - I am a professional photographer, so posting poor quality smartphone shots is inexcusable! Feedback or advice is most welcome.

 

 

[LordTrilobite]

Glad to hear you're continuing this project. I would be careful with dampness on the bones themselves though. It might make them more fragile. Removing those last matrix remnants might be useful as well as the pieces will be easier to identify.

 

 

Looking good on the progress so far.

[Aurelius]

Thanks, I have been hard at work! I have now cleaned pretty much all of the matrix off the bones, except where it is cemented on by a ham-fisted attempt at prep when it was still in Morocco. I'll apply some acetone to those bits and see if I can get it off.

 

Speaking of ham-fisted prep, can anyone take a guess at what's going on here?

 

I may be wrong, but it appears that the bones on the right are completely unrelated bones which have been glued on (the right side is twice as thick as the left side, too). I think this might also need some acetone to dissolve the glue and separate these pieces.

 

Then the hard work begins - identifying which bone goes where and working out how to mount them all!

 

 

[Aurelius]

Actually, I think perhaps that bone is meant to be there, though the angle may not be quite right. As I say, lots of anatomy to brush up on!

[Aurelius]

I have spent a couple of hours laying out the bones and trying to sort out what I have, and what is missing. It's very difficult, because I'm not a reptile specialist and the resources at my disposal are limited. I was only able to locate a single academic reference ('A new description of the skull of Dyrosaurus phosphaticus (Thomas, 1893) (Mesoeucrocodylia: Dyrosauridae) from the Lower Eocene of North Africa') and there are few detailed, high resolution photos out there. Plus, when you see a specimen for sale, you don't know how accurately it's been mounted or prepped.

 

Some of my assumptions are surely wrong, but here is what I came up with, along with this rough sketch showing how that translates into what I have, versus what I don't.

 

 

 

I also have these bits that I can't, as yet, identify. 

 

 

Any ideas would be welcome. I really need to work out what those missing bits are before I can do much else, although I also have to clean the bones a little more (I can't remove any more without using solvents to dissolve glue that was applied in Mocrocco, so I want to do that safely and carefully when I have the time).

 

[RJB]

I don't mess with 'bones' too much so not much help I can be, but looks to be a very fun yet complicated project.  The best of luck to you.

 

RB

[LordTrilobite]

Oh so you have the premaxilla after all. That's shaping up to be a pretty croc skull.

Small fragments like that can indeed be really hard.

 

My suggestion would be to look at recent croc skulls. The overall shape might be a bit different. But many details will be the same and could greatly help in figuring out where all those weird little bone pieces would fit. The best thing would probably be to get a hold of an actual croc skull. Nile crocodiles are used for meat and leather on farms. But the skulls are also sold. The smaller ones can be pretty inexpensive too, you wouldn't need a bigger one anyway since it's about comparing shapes. And there there is nothing better than holding real bones in your hands for reference.

 

Once you have a better understanding of crocodile skull morphology. Then compare it to the reference for Dyrosaurus again and see how things differ.

[Aurelius]

Thanks, that's a good tip. I've ordered a small crocodile skull and am hopeful that will be useful. I'm also going to try and see whether I might be able to see/photograph a mounted specimen somewhere.