Hadrosaur Humerus Repair/Prep

[LordTrilobite]

I recently got this lovely mess of bone, which is a mostly complete hadrosaur right humerus that only requires some assembling. I actually bought this with the idea that it might be a fun project. But then it broke even more in the shipping. So I have my work cut out for me. It's from Judith River formation, Montana. It's hard to tell at the moment, but it seems to be a rather slender humerus. So that would make it more likely to be from the saurolophinae subfamily. But I will look into that some more when I have it assembled.

 

So I will be doing lots of reassembling on this piece as well as prepping away some excess matrix that's still present. Besides the obvious problems, the bone itself is actually in very nice condition with some really smooth cortical bone as well as some lovely visible muscle scars.

 

This is how it looked when I first opened it. Quite a mess. Also a drawing of what it should look like in context.

 

And here I have slightly ordered the pieces. There's 5 big main pieces, three medium pieces and a whole bunch of tiny chunks.

 

 

One of the bigger pieces that includes the ulnar and radial condyles. The shaft of the bone has had a pretty bad recent fracture. This is also where most of the smaller pieces come from.

 

[LordTrilobite]

So here is some of the initial prepping. I've started to remove some of the matrix from the outside. And sadly there's also some matrix as well as glue in some of the breaks. So I will have to remove that to make all the pieces fit back together nicely without creating large gaps.

 

Some closeups of some of the larger pieces.

 

Here I have done some work on piecing together the largest gap where most of the small pieces come from. I've gotten many of them back in place.

 

Some pieces that glued back on the other bone that makes the top of the broken shaft.

[Xiphactinus]

Good luck!

[LordTrilobite]

Being in so many pieces, this also offers the opportunity to see inside the bone. And there are some quite nice breaks that show the internal structure.

Interestingly, even though the bone is preserved nicely in 3D, much of the main part of the humerus has collapsed slightly. Even when put back together, there will be some shifts in bone that I won't be able to put back into it's original place.

 

Some closeups that show the thick cortical bone wall that is mostly intact. This is followed by some intact spongy bone. But in the very core of the bone, the spongy bone has collapsed into a solid stony mush.

[caldigger]

Hmm, better stock up on chewing gum.

I'm sure you'll do your best and show us a surprising outcome. Let us know.

[Ptychodus04]

That’s quite a puzzle. Good progress thus far.

[LordTrilobite]

I've made a whole bunch of progress during the weekend. So here are some more photos. I've already put many hours into it. Mainly removing the excess glue takes a lot of time. Here I've cleaned most of the large pieces. I've glued in most of the tiny pieces that I could find the correct location for. There's still a bunch of tiny pieces I have left, but I'm not sure I can find where they all go. But then most of those pieces are really small. I have all the big ones in place. Though I will likely be using some putty to fill in some of the gaps that remain when I am finished piecing it back together. It's mainly the tip of the deltopectoral crest that I still need to clean.

 

I have also glued most of the proximal end of the humerus. This was originally in four main pieces when I got it. 2 large 2 medium. Also some photos of the top and bottom. At the top one of the missing pieces can be seen. I don't have that piece sadly. There was some matrix on the break and I think it might have broken of shortly before the bone was found. The break again clearly shows the spongy bone that has collapsed into a solid mush. What also becomes clear now is that the proximal end of the humerus has shifted. It seems this has happened some time during fossilisation. Some areas are too crushed to properly put back into place so I'm leaving this part as it is.

 

More to come soon...

[Abstraktum]

You are doing a great job on this restoration project. Really looking forward to more pictures and updates  

[LordTrilobite]

Here is some more progress. I've cleaned most of the tip of the deltopectoral crest. Normally the matrix is very soft, but in places where the matrix was glued it can be very hard. In these places it can be quite difficult to prep the fragile bone. Though sometimes whole chunks of matrix pop off cleanly without damaging the cortical bone. So that's always really satisfying. There are some nice muscle scars visible on this part. But there is still quite a lot of glue I need to remove from the break surface to make it fit back properly.

 

 

 

Besides the deltopectoral crest, I have glued back all other big pieces. It's starting to look quite nice again. I quite like the colour of the sun bleached parts as well. After glueing I found out that the whole bone is actually unusually slender. Looking at lots of reference I'm pretty sure it's from a saurolophine hadrosaur. It's also quite different from my other two hadrosaur humeri, which I think most resemble Gryposaurus latidens. Besides being more slender there are some other differences as well. Right now I'm leaning towards this possibly being brachylophosaurin (This includes Brachylophosaurus, Probrachylophosaurus and Maiasaura). Though the bone is from Judith River, where Maiasaura is not described.

 

Roughly where the last piece would sit after I clean off all the extra glue.

[Troodon]

Nice work

[Natalie81]

Well done! 

[Randyw]

Looking good!

[Ludwigia]

That's quite a project of patience and precision which you've taken on and you're doing a great job at it!

[Haravex]

Really nice piece and prep work you have done there LT

[Flx]

Great job! 

I find it very impressive that you managed to put the pieces back together. From my experience this is difficult once the parts are not connected to the matrix any more (pieces in completely random position/orientation drive me crazy). Therefore I prefer fossils being collected in plaster jackets. 

[Xiphactinus]

Nice! That’s beautiful work. You actually put Humpty Dumpty back together again!

[Bobby Rico]

Looking good. Nice thread too. 

[JohnBrewer]

Superb, Olof!

[LordTrilobite]

Thanks for all the comments!

 

So I have finished the reconstructing process.

I've further cleaned the broken surface of the remaining piece that is the tip of the deltopectoral crest. After which I reattached it into place. It was impossible to get everything to line up exactly right due to the crushing of the fossil I have mentioned earlier. So that's all the pieces back into place. I have also managed to put back a few more of the small pieces. I have some more pieces to spare, but those are very small and I can't for sure find their correct original orientation on the bone. So I likely won't be glueing those back into place.

 

As I said the bone has some crushing. With it being back in one piece again I can see sorta what has happened to it. Part of the concave area on the front around the deltopectoral area has collapsed and caved in. This has resulted in this whole area sorta closing in on itself like the closing of a hand. As a result this area has become more concave and the deltopectoral crest is pushed inwards to the medial side.

 

I'm not quite sure I'm done yet. Initially I intended to use putty to reconstruct the missing areas and fill in the gaps. But now that I see the whole thing I'm not so sure. I will at least not be reconstructing the missing bit on the top of the humerus due to the shearing of the top end. It wouldn't look right since the rest of the top has slid down. I won't be removing this misplaced top due to it being a bit fragmented and bunched on the lower side of it. If I had a sandblaster I might reconsider, but for now it stays as it is. But I might still putty the other areas of the humerus that don't have as much significant crushing or deformation.

 

I mentioned before that the bone seemed slender and that it's likely from a saurolophine hadrosaur and possibly brachyolophsaurini. And it does match most closely to both Maiasaura and Brachylophosaurus. Maiasaura is unknown from the Judith River formation and it also has a slight difference in the distal end of the humerus where it seems to have a stronger curve. And Brachylophosaurus matches pretty nicely, and it's also one of the more common hadrosaurs from the Judith River formation.

So unless I find more information I think I will likely be labeling this as cf. Brachylophosaurus sp.

 

I really love how this piece turned out so far. The texture and colour of the cortex is really quite good.

The whole bone is about 36 cm long (14 inch), but it would have been longer due to the shearing of the top. It might have been roughly 41 cm long (16 inch).

Click the images to enlarge.

 

Closeups

[Xiphactinus]

excellent work. As always. You have a really cool specimen.

[RuMert]

Incredible patience, seeing that poly with pieces I would throw it out the window in anger

[FossilDAWG]

That's a puzzle worth spending the time on.  Great job! 

 

Don

[Randyw]

Wow! Great job and great specimen!

[caterpillar]

Great job. Have you stuck all the pieces or do you have any left?
When I dismount an engine, I still have a bolt

[LordTrilobite]

17 hours ago, RuMert said:

Incredible patience, seeing that poly with pieces I would throw it out the window in anger

I can actually be quite impatient. But honestly, for me patience really isn't a factor in this sort of thing. I just methodically go through all the viable options and that results in a puzzle that is pieced back together. Sure it can be frustrating if you can't find the right piece. But this specimen consisted mostly of fairly large chunks that I already knew where they were supposed to fit. So it was just the small bits that I needed to place correctly. And it's always a thrill when you find a match.

 

5 hours ago, caterpillar said:

Great job. Have you stuck all the pieces or do you have any left?
When I dismount an engine, I still have a bolt

I do have some bits left. But only smaller than 1cm. All the larger pieces are in place. There's really only one prominent piece that's completely missing. On the proximal end next to the sheared top it's missing one end on the lateral side. Other than that there's only some gaps here and there where I also don't have the pieces. I think it was already fairly broken up when it was found in the field. Probably just weathering. There's some sun bleaching and there was some green on it as well. So that suggests it was exposed to the elements for a bit. So I'm thinking some smaller pieces went missing during that time. And after that it was likely roughly put together and glued. Which might be why the breaks were generally pretty clean apart from washed in matrix that was glued on, which I then had to remove.