My last post was about the finished Tupuxuara. It was finished, since I did my best with what I had: great fossil pictures. But I only had one side view of the lower jaw. So I was able to make the mandible look like the one in the picture but had to imagine what it would look like from above, below and inside. I used the upper jaw and palate as a starting point, but I was wrong. Shortly after I finished the skull I received the photos of the mandible: it doesn’t match the format of the upper jaw as I thought it did. It is wider on the sides and narrower at the back. The sides are almost parallel from the middle to the back. The mandible body is much larger. There are also many other small details I left out.
So then I had to decide beween making a new one or fixing the one I have. Since the existing incorrect mandible is already in the correct size, and similar (at least when viewed from the sides) to the correct one, I decided to fix it.
I still don’t have authorization to post the pictures of the fossil here to compare the results, but you can see them in my computer screen.
So here is the plan. I matched the photos in scale to the previous ones I used before, and drew a guide on paper.
From that guide I cut out a piece of foam to start filling in the gap which was too large, and to help reshape the jaw:
First I glued the tip in place so I could mold the arms of the mandible twisting them slightly outward and downward, shaping it like the picture.
After that, I scraped the acrylic resin to expose the foam and make gluing more efficient.
And held everything in place until it was dry. Now the shape of the mandible already resembles the correct one.
I reinforced the insides since I was twisting the foam a lot and then I worked on the other side, which has some ridges (which I could see from the side view) and a concave center (which I could not see from the side view).
After these changes the mandible had the correct shape, but the sides were no longer vertical but flatly slanted outwards. I added some foam on the top sides of the outer arms of the jaw to compensate this.
Then I did some finishing with fire. This is the result.
I also had some photos showing the insides of the mandible arms. Just one angle though, and not very detailed, but enough to add see two small cavities on either side which I added to my model.
When everything was dry I finished it with fire, covered it with a layer of acrylic resin and let it dry overnight. The next day I stained it with coffee.
And that’s it. Now Tupuxuara has the right jaw. Below are some photos of the finished mandible and of the skull with the mandible attached.
Top, bottom and side views
This is the bottom
This is the top
And these are the sides.
Here are some views in different angles.
And a close-up showing the mandible body
Tupuxuara with mandible attached
Here are some photos showing the mandible attached to the skull.