Category Archives: Pterosaur #3: Tupandactylus

Tupandactylus imperator, a Brazilian pterosaur

Pterosaur #3: Tupandactylus imperator (finished skull)


That’s a Tupandactylus skull mounted on my balcony with São Paulo in the background on a sunny Sunday morning. To learn how I made it, check the links at the end of this article (or read the posts under the category Pterosaur #3: Tupandactylus in reverse order).

To make it I used the following material:

  1. One 1.0 x 1.2 m sheet of XPS foam board, 5mm thick (I used ~ 50% of it)
  2. 100g PVA (polyvinyl acetate) glue (adhesive for foam)
  3. 200 ml of modeling paste (acrylic resin)
  4. Less than 2g of epoxi resin (for reinforcing the jaw articulation)
  5. Cotton gauze
  6. Several stains (coffee, ashes, yellow and brown gouache paint)

These are its dimensions:

  • Length of the skull from the rear crest to the beak: 108 cm.
  • Length of the skull from the top crest to the beak: 123 cm.
  • Maximum width of the skull (near the jaw articulation): 11 cm.
  • Height of the skull from the top crest to the jaw articulation: 100 cm.
  • Length of the mandible: 49 cm.
  • Maximum width of the mandible: 10 cm.
  • Maximum height of the mandible: 13 cm.
  • Weight: 500 grams.

I’m declaring the skull finished but there are many things that can still be improved and corrected. I did not find reliable or sufficient information about the palate nor the structural bones beneath the skull, so they may be incorrect. I can always fix that in the future when I have better pictures, access to fossils or reliable models. I also have to study some pterosaur anatomy!

Here is another view of the skull on the floor by the books.


And on the table (near my falsification of Delacroix’s Jeune Orpheline au Cimetière):


Below are some photographs at different angles, close-ups and details.

The mandible



Front and top views



Top and back views


This is the rear crest showing the temporal apertures at the back of the skull.



Bottom and back views





Close-up of the skull



With the mandible detached



With the mandible attached





Now I need to make the body, but it will be speculative since only fossils of skulls have been documented for this pterosaur; nothing else. I should use Tapejara wellnhoferi as a starting point, but I still haven’t found any good diagrams or drawings of the vertebrae online.


I have already mentioned the sources I used for this model in a previous post, but I am listing them below for convenience.

  1. Tupandactylus fossil: holotype 1 (MCT 1622-R)
  2. Tupandactylus diagram, by David Peters, based on MCT 1622-R
  3. Tupandactylus fossil: holotype 2
  4. Paleofile entry on Tupandactylus
  5. Article: Campos & Kellner, 2007: Short note on the ingroup relationships of the Tapejaridae (Pterosauria, Pterodacyloidea)
  6. Article: Pinheiro et al, 2011: New information on the pterosaur Tupandactylus imperator, with comments on the relationships of Tapejaridae.
  7. Tapejara diagram, by David Peters
  8. Tupandactylus illustration, by John Sibbick
  9. Reconstruction of the skull of a Tapejara wellnhoferi,
  10. Fossil reconstruction of a Tupandactylus imperator, by
  11. Tupandactylus replica, at Museu Nacional do Rio De Janeiro (photo by Magerson Bilibio)

How to make a Tupandactylus skull out of foam

Do you want to know how I made it? These are all the posts documenting the making of this model, in order:

  1. Feb 24: I found a Tapejaridae pterosaur in a board of foam!
  2. Feb 25: Inside a pterosaur’s head
  3. Feb 27: Tupandactylus skull details and mandible
  4. Feb 28: Pterosaur #3 almost done
  5. Mar 2: Tupandactylus: reshaping crest and orbits
  6. Mar 3: Pterosaur #3: Tupandactylus imperator (finished skull) (this post)

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Tupandactylus: reshaping crest and orbits

The rear crest is flat since I started this model. Today I reshaped it to make it three-dimensional. I also added an extra layer of foam to the orbits, because just molding the foam was not enough.

First I removed the layer of acrylic resin around the orbits.


Then I added a sheet of foam in approximately the same shape.


Then I did some carving, molding and a bit of burning.

For the rear crest, I added an extra bone on each side, and then filled in the spaces with pieces of foam making it slightly wider near the middle, but narrower below and very narrow above (where there would be soft tissue). Here are some pictures. This is a side view.


A view from the far end of the rear crest.


A view from above.


And a view from below.


The next step is to add a layer of acrylic resin (and some gauze, if necessary) to fill in the gaps, sand it a bit, add some stains and colors and finally declare this skull finished.

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Pterosaur #3 almost done

I am making two skulls at the same time. It’s more productive. When one is drying I work on the other. So now the Tupandactylus is nearly finished. It just needs some work on the rear crest, some sanding, staining and that’s it. This is a close-up of the head with the mandible in place (I already finished the mandible that’s why it is in a different color).


This is what it looks like when you are behind a dead Tupandactylus.


And when you look down at it from above.


And here is another family portrait, this time showing the still unfinished Imaginary Pterosaurs #3 (Tupandactylus) and #4 (Unnamed Toothless Dsungapterid).


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Tupandactylus skull details and mandible

Almost all the foam work is done for Tupandactylus. Now I will coat it with acrylic resin and use gauze + resin to fill in cavities. This the mandible.

mandible foam

This is the inner part of the mandible. These cracks I will fill later with the acrylic resin (modelling paste).

mandible foam inside

I also worked on the details inside the head, the brain case, the orbit and temporal cavities. This is a view from the back of the head showing the upper temporal fenestra and parietal bones.


This is the back and bottom of the skull. The shiny round piece of plastic on the left side is part of the occipital bone, where the cervical spine will be attached. I have to reinforce this later with epoxy resin since I hope to be able to make a detachable yet strong connection for the spine.


I still do a lot of guesswork since I don’t have enough pictures of the pterosaurs I am making, and I have only just recently started studying a bit about skulls. I am, as usual, relying on the fact that I can always fix it later as I have done so far: research a bit, do it, see what is not right, research again, fix it, and so on. It is a good method because I can quickly start working on a three-dimensional sketch. I can test it and see what does and does not work (instead of spending a long time investigating drawings and pictures and reading scientific papers that I do not have enough background to yet understand). By testing, I can better understand the structural purpose of each bone, and it helps me direct my research to the problem I need to solve. When I do additional research after that, it is much more productive, and interesting. When I read a scientific paper after working on a 3D model, I can understand a lot more.

The Imaginary Pterosaur family

While I am making the Tupandactylus, I am also working on a toothless dsungaripterid. Here is a family portrait of all four Imaginary Pterosaurs.

four pterosaurs

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Inside a pterosaur’s head

Yesterday I worked on the details of Tupandactylus’s skull. I didn’t find any detailed information anywhere. It seems that there are only four Tupandactylus fossils, and they are all flattened out and incomplete. So I invented the inside of the skull borrowing from Anhanguera, Tapejara, and from my imagination (I have no idea what it should look like under the eye cavities). Well, this is the Imaginary Pterosaur project. As usual, in the future, if I have enough information I can always fix it (and if anybody reading this knows about Tupandactylus or about how I could improve this skull: specially the details inside the head, images, descriptions; I would appreciate any help.)

This is the skull after attaching both halves together and molding.


These are just two halves cut from a 5mm think XPS foam sheet, glued together at the edges, and molded out by folding (it won’t snap if you press before folding – see the previous post).



It is still too flat, of course. I pasted pieces of foam on the inside to help shape the head, and then added some “bone” inside the beak.


I also added a piece of foam just below the braincase to help keep the head rounded. It’s a sketch of the occipital bone. Later I will reshape it, add the cavities and the protuberance which attaches to the first cervical vertebra. For now, it is just a flat surface. I don’t know if these bones in the middle really exist (I urgently have to study vertebrate skull anatomy), but it’s working great so far to keep everything in place.


I worked a bit on the mandible. I still have to close it on the inside. I also discovered that it is too short and doesn’t really fit well with the upper beak, so I will have to do some reshaping later.


Here are some views of the upper skull. I used a lighter to change the texture of the foam with fire and to harden the surface a bit. It also makes it look more like a bone.

topside 2013-02-25 10.21.01 2013-02-25 10.20.50

I can’t connect the mandible yet, but we can already see what it would look like.



So this is the skull of the Tupandactylus imperator after two days of work. Not counting the time I spent on research nor the time I had to wait for the glue to dry, I spent, so far, 8 hours on this sculpture.


I will have much less time this week, but I believe it will be enough to finish this skull by Friday.


Below is some information about my research.

I first sketched the profile from this Tupandactylus diagram. Later I layered it with these two fossils: MCT 1622-R (on which it is based) and this other one. Other information I took from this Paleofile entry, this article by Campos & Kellner (2007), and this article by Pinheiro et al (2011).

I used this Tapejara diagram for inspiration about what the Tupandactylus should look like when seen from above, and this drawing for an idea of what it might look from the front. I also used this reconstruction of the skull of a Tapejara wellnhoferithis fossil reconstruction of a Tupandactylus imperator and this picture of a Tupandactylus replica from Museu Nacional do Rio De Janeiro.

Thanks to Hebert Bruno Campos for the links to several of the references above.

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I found a Tapejaridae pterosaur in a board of foam!

It’s a Tupandactylus imperator. I started with a 1.2 x 1.0 m board of XPS foam 5 mm thick. There aren’t so many Tupandactylus holotypes and there are none in good shape. I will have to guess, invent, and copy some solutions from Tapejaras. I started with a draft based on the best fossil.

2013-02-22 23.54.59

But I ran out of foam. It was only enough for the mandible and half a skull. When I got more foam it was of a different kind, so I decided to cut out two new halves, without the full front crest (I will add it later) using the previous half as a guide. I also did some research and decided to leave the skull’s details out for now.

2013-02-24 00.56.49

Before pasting the halves together, I trimmed the edges on the front and top of the crest to make it easier.


Then I folded the foam. This is important so it won’t crack when manipulated. You have to press and fold. You can even fold all the way if you do it right. After folding in one direction, in some parts, I folded in the other. It becomes a lot easier to mold with this previous folding.


Don’t forget to press before folding, or the foam will crack. Do it until the foam becomes softer and easier to mold.


The next step is to glue the halves together. After adding glue on some edges and holding the parts together for a while, we finally have something that looks like a Tapejara.

2013-02-24 00.58.44

After drying, another hour of folding, and finally we have this.

2013-02-24 01.00.47

In the morning, after the glue dried a bit more, I cut a cavity behind the eye and now we finally have a 3D sketch to start working on.



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A new family member

The Imaginary Pterosaur family will soon have a new member: Tupandactylus imperator. Anhanguera’s body is also on the way. These are the skulls of the three imaginary pterosaurs so far (on a 1.00 x 1.20 m sheet of XPS foam):


Anhanguera has also gained new front (rostrum) teeth (it looks a lot more like the fossil now), and brain cavities; I also improved the shape of the head and the eye cavities.

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