Category Archives: Pterosaur #5: Tupuxuara

Tupuxuara leonardii, a Brazilian pterosaur

Presentation at the Dinosaur Symposium

The 1st Brazilian Dinosaur Symposium did more than just provide an exhibition space for paleoartists. They also invited us to speak about experiences, techniques, to show and discuss our work in sessions that filled the main auditorium. These are the slides from my presentation about this project (focusing on the Tupuxuara skeleton which was assembled during the symposium).


If you don’t have a Scribd account (or if you never uploaded anything there) you might not be able to download it (only browse online) unless you pay. But you can also downnload it from here (PDF with 180 MB).

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Making of a Tupuxuara

These are all the posts about building the Tupuxuara reconstruction.

  1. March 7 Starting pterosaur #5: Tupuxuara leonardii
  2. March 8 Tupuxuara: adding a palate
  3. March 8 Tupuxuara: the mandible, some trimming and molding
  4. March 9 Tupuxuara: details, details
  5. March 10 Pterosaur #5: Tupuxuara leonardii (finished skull)
  6. March 12 Tupuxuara: fixing the jaw
  7. March 17 A neck for Tupuxuara
  8. March 24 Tupuxuara: two more cervicals
  9. March 25 Tupuxuara: the chest
  10. March 28 Tupuxuara: thoracic vertebrae and the notarium, part I
  11. April 2 Tupuxuara: thoracic vertebrae and the notarium, part 2
  12. April 4 Tupuxuara’s shoulders: the scapulocoracoid
  13. April 4 Tupuxuara: planning the wings
  14. April 6 Tupuxuara’s wing: the humerus, radius and ulna, part 1
  15. April 8 Tupuxuara’s very long fourth fingers
  16. April 9 A hand bone
  17. April 10 Tupuxuara’s wing: the humerus, radius and ulna (final)
  18. April 12 Legs for Tupuxuara
  19. April 14Tupuxuara: the pelvis, sacrum and dorsal vertebrae
  20. April 15 Tupuxuara’s wrist: the carpals and pteroids
  21. April 17 Tupuxuara: the tail
  22. April 17 Pterosaur claws
  23. April 17 Pterosaur feet
  24. April 19 Tupuxuara leonardii: assembly (and disassembly)

Update – New posts about Tupuxuara

  1. May 30. The Making of Imaginary Pterosaurs. PDF presentation at Rio Ptero 2013, International Symposium on Pterosaurs.
  2. May 29. Imaginary Pterosaurs in Rio. About Rio Ptero 2013, International Symposium on Pterosaurs, where Tupuxuara was assembled for the second time.
  3. May 21. First prize for Tupuxuara. My Tupuxuara leonardii replica won first prize in a paleontological art contest (I Concurso de Arte Paleontológica do Colecionadores de Ossos), category sculpture.
  4. April 27. Presentation at the Dinosaur Symposium. PDF presentation at the 1st International Dinosaur Symposium.
  5. April 27. Pterosaurs at the 1st Brazilian Dinosaur Symposium. About the 1st International Dinosaur Symposium in Ituiutaba, MG, Brazil.

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Tupuxuara leonardii: assembly (and disassembly)

Here are some pictures of the finished skeleton.
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It stood complete on my table for less than a day. At night I started disassembling it.


Here is the dismantled pterosaur.

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Everything weighs less than one kilo. I had to make a box big enough to fit the head.

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I found some space to place two other skulls and mandibles in the box. Everything weighs five kilos.

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We are traveling to the First Brazilian Dinosaur Symposium, in Ituitaba, MG, Brazil.

Soon I will write a final post on this pterosaur, listing my sources, references, materials used, and listing all the related posts in chronological order.

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Pterosaur feet

It’s finished! In a previous version of this post I had mentioned that I still needed to make the ankle. I don’t. The tibia in adult pterosaurs is not only a fusion of tibia and fibula, but also of the proximal metatarsi called astragalus and calcaneum (the ankle bones). So I don’t have to make any proximal metatarsi (I took an hour to discover that looking at the tibia ends and diagrams of the metatarsi.)

Some bones are missing, and I might add them later. They are 1) five more sets of ribs (2 thoracical, 3 dorsal), 2) gastralia ribs and the 3) pre-pubis (which connect the pubis to the gastralia via cartilage).

I made de feet based on Tapejara and material from an undescribed Thalassodromid. They have the same proportions as Pteranodon, except that the nails of the Thalassodromid are larger. So I used Pteranodon (drawing by Wellnhofer) as a reference and made larger nails.


Here is how it will be assembled. I can’t yet connect it to the tibia bone because I still didn’t make the heel bones (distal metatarsi).


Oops! That’s the wrong end of the tibia!

Here are the two feet in their natural position. I will attach the bone with silicone rubber, but for now I am just going to test so I will connect them with pins.


Here you see two feet on the table near an Anhanguera skull and below some Tupuxuara claws 🙂

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The proximal tarsi (the ankle) are fused with the tibia (the whole bone is called tibiotarsus) so we don’t have to make them. But we do need to make the distal ones (the heel). I used Tapejara carpals (scaled for Tupuxuara) from an article about ankle structure (Kellner 2004). This is the side that connects to the metatarsals.

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And this is the side that faces down when the pterosaur stands.

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The five metatarsi connect to the two distal tarsi.

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Here are some pictures of the final results (the pins are temporary: I will later connect these bones with silicone rubber). This is the right foot.


This is the left foot.


A view of the ankle and heel bones (left foot).


Looking down from the top of the tibia (left foot).




Walking pterosaur.


More claws.


That’s it. In my next post I will publish several pictures of the Tupuxuara assembled in this position (I will assemble it in another position next week). Then I will unassemble it, weigh the skeleton and pack it. It will travel tomorrow to a paleontological conference in Minas Gerais, Brazil.

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Pterosaur claws

I have several photos of individual finger bones from yet undescribed species which might be Tupuxuara. I also have pictures of the fingers of Tapejara wellnhoferi. But I only have photos of the bones of Tapejara from one angle, in black and white and in low resolution, so I can’t really see if they are flattened out, or curved in some direction. I assume they are straight comparing to the other photos I have (unfortunately I can’t post any of those pictures here, since they are all unpublished research). I compared different drawings of pterosaur hands and they seem quite similar. The number of phalanges is the same in all pterosaurs. Including the nails, the pattern for fingers 1-4 (where 4 is the wing) is 2-3-4-4. The sizes, the widths and the shape (curved, straight, flattened) of the phalanges differ across different species. As to the proportions, I found no great differences between some drawings of Tupuxuara hands (from which I have no sources), Tapejara and Pteranodon. So I used this drawing by Wellnhofer, scaled it to mach the size of my Tupuxuara skeleton, and used it as a guide to carve the fingers.

Here are the fingers and metacarpals after carving.

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These are the finger bones and nails before assembly. I already pinned the metacarpals together.

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I have to turn the metacarpals a bit, but this is how the fingers will be assembled.

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Here are Tupuxuara’s claws after assembly. I am using pins to test, but I will later keep the fingers and metacarpals together using some cartilage (silicone rubber). If I use pins all the time it will weaken the foam.

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Now I placed the metacarpals back on the skeleton with the claws in place.

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Here are some other angles showing the left hand.

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This is the right hand.

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Tupuxuara: the tail

There are not many preserved pterosaur tails. I had initially planned to make Tupuxuara’s tail from Pteranodon until a friend told me to look for the tail of Anhanguera piscator. So again my source is Anhanguera (Kellner & Tomida, 2000). I estimated its size,  printed a guide and made eleven caudal vertebrae.

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These are the finished vertebrae.

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To assemble the tail I used a plastic “spinal chord” (made from a plastic hanger) inserted in the tube that I used as the chord inside the pelvis. For now I just fit the vertebrae there. Later I will also attach them together with silicone rubber discs.

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And here is the tail in place. It probably has more than 11 vertebrae. Pteranodon’s tail has two very long vertebrae at the ent, but since this is not even Tupuxuara’s own tail, I decided to leave it as is.

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Tupuxuara’s wrist: the carpals and pteroids

The carpals are seven little bones which connect the metacarpals, pteroid and radio-ulna pair together. I had no sources for Tupuxuara, and after spending a day trying to make a pair of syncarpals (fused carpals) from Tapejara, I decided to use Anhanguera as a source. So my Tupuxuara’s wrist actually belongs to Anhanguera.

There are five distal carpals, and four of them are fused together so they actually act as two: the distal syncarpal, which articulates the hand metacarpals, and the pre-axial carpal which articulates the pteroid. There are two proximal carpals, also fused, which connect to the radio-ulna pair. I used Anhanguera (Kellner and Tomida 2000) which provides four views of the proximal and distal syncarpals. I made up the medial carpal (roughly based on other pterosaurs and drawings). I adapted the pteroid from Pteranodon and adjusted its size by a low resolution Thalassodromid fossil photograph (it was not good enough to use the photo as an image source, but I could calculate its proportions relative to the radio-ulna.

This was a first test carving just the two syncarpals, but I didn’t use it. I decided to make individual carpals.

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I printed the four views of each syncarpal and coloured each carpal differently to make it easier to identify them on each view.

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Then I carved the individual carpals from 3 cm XPS foam. These are the carpals that form the left and right distal syncarpals.

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This is the distal syncarpal assembled (showing the side that articulates with the proximal syncarpal).

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These are the parts that make the left and right proximal syncarpals.

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And these are the proximal syncarpals assembled.

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Since they are usually fused (in mature pterosaurs), I glued them together with silicone glue (which retains some flexibility). Here is a view of all the syncarpals (showing the sides that connect to each other).

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Now the other side. This is the side that connects to the bones (proximal syncarpal to radio-ulna, and distal syncarpal to the wing metacarpals.

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Anterior view.

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Posterior view.

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This is the distal end of the radio-ulna pair with the carpals connected. The bone that is pinned at the right is the pre-axial carpal. It articulates with the pteroid (via a sesamoid bone) and with the distal syncarpal. The Anhanguera specimen I used as a source didn’t have one so I “invented” one based on some photos of Pteranodon fossils (I used the article “Articulation and Function of the Pteroid Bone of Pterosaurs”, by S. C. Bennett, 2007 as a source).

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Here are some side views.

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Now the pteroid. It has a very thin and fragile tip. To make it stronger I stretched a piece of PVC plastic (from a plastic hanger) to serve as a bone skeleton.

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I used two halves of 5 mm XPS foam, and a plastic bone skeleton.

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Opened a cavity on both sides and sandwiched the plastic skeleton inside.

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After carving, staining, etc. we have a pair of pterosaur pteroid. Here is the full collection partially connected. The pteroid connects to the sesamoid bone, which connects to the pre-axial carpal, which connects to the distal syncarpal, which connects to the wing metacarpal.

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And now our Tupuxuara has a wrist and pteroid.

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We still need fingers (including metacarpals), feet (including ankle bones), tail and pre-pubis. I’m not sure I will have time to include the pre-pubis this week. I might leave it for later when I plan to make some minor fixes and possibly introduce new ribs, gastralia and cartilage (in silicone rubber).

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Tupuxuara: the pelvis, sacrum and dorsal vertebrae

The specimen I have been using as a source (IMNH 1052, Iwaki Museum, Tokyo) has no pelvis, sacrum or any other dorsal vertebrae. I already made all the bones from that source. The sources I used for this pelvis were kindly sent to me by Mark Witton, and belong to a related species (possibly a Tupuxuara).

My sources were four views and a diagram from where I calculated the size of the pelvis relative to the other bones. The right view was the best, so I used it to sketch the pelvis bones. I sketched the sacrum from the dorsal view. There was also a posterior view, which I used later.


I cut the parts slightly larger so they could be molded.


First, I assembled the sacrum gluing the two halves together (by the spinal crest).


Then some trimming, and let it dry.


I was in a hurry to see what the pterosaur would look like with a pelvis, so I pinned the parts together and let the sacrum dry hanging on its “spinal chord”.


Then I added some foam to the other side, to shape the sacrum, and compared it to a diagram I made from the sources.


While that was drying, I worked on the sacral and dorsal vertebrae, carving a spine from thick foam. Here I lined up the sixth thoracic vertebra (the last one from the notarium), three free lumbar (dorsal) vertebrae, and seven fused vertebrae.



I tested it before attaching the parts.


I had no source for the three lumbar vertebrae, so I invented them based on the others.


Here are the vertebrae lined up.


And here is the first one that articulates with the pelvis in place.


As a spinal chord I am using plastic tubes of different widths. I insert the thin ones into the wide ones. There is a spinal chord for the cervicals, for the notarium and for the pelvis. The tail vertebra will be mounted on a thin rigid plastic spinal chord, which will be inserted in the thinner tube (the white one in the picture below).


Time to attach the pelvis. First one side.


Then the other. I always twist and fold the foam before attaching.


Some parts need more work. Here I am trying to shape the pubis while keeping the ischium in place.


The two halves are not enough to provide all the three-dimensional details I need for the pelvis, so I made some “masks” with 5 mm foam which will allow some shaping.


I also added some foam at the sides of the ilium to shape a small iliac crest (extending from each side of the sacrum). From the pictures I don’t know the exact shape of the ilium (I have no frontal view, and it’s partially damaged), so I looked at some other pterosaurs and chose something which matched the picture. This is the pelvis seen from the inside after most of the foam shaping.


Another view.


And here’s a dorsal view.


Now the resin coating, coffee staining, and we’re done. Here are three views of the pelvis. This is the left side.


This is a dorsal view.


And this is a ventral view.


The pelvis is a complex set of bones. I don’t know if I achieved in making an accurate one. I did my best with only three views. I’m not really sure if I should have closed the ischium. If I get more data in the future I will fix any mistakes.

Here you can see it in other angles.






Now finally I can attach the legs. Here are two pictures of the pelvis in place with the femora attached.


from behind

This is what it looks like when you are underneath a pterosaur skeleton.


It saw us and it’s coming this way!

almost done

What’s next? I don’t know. As you can see from the pictures above, some bones are connected with rubber bands: I still didn’t make any carpals. I will have to invent carpals, fingers, toes, and tails. I have none of them. They are small and simple bones, so there is a good chance that I might finish this skeleton tomorrow.

I already have some sources but I am still interested in any new ones. If I have more information I will be able to make a more accurate model. I am interested in pictures or drawings of feet, tails or hands of a Tupuxuara, Thalassodromidae, or even a related species. If you have any, send me an email!

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Legs for Tupuxuara

These are the last four bones from the Iwaki Musuem Tupuxuara specimen I am using as a source. I am making the pelvis from another source. All the other bones (carpals, pteroid, fingers, feet, tail, nails) will have to be invented. I’ll probably diagrams and fossils from other pterosaurs as sources.

The femur is the leg bone that articulates with the pelvis. The tibia is almost as long as the first wing phalanx (it’s the fourth longest bone after the skull, mandible and first wing phalanx). Pterosaurs are tetrapods and as such also have a tibia-fibula pair, but the fibula in some species is not much thicker than a metacarpal bone. And sometimes it’s almost invisible, since it’s usually fused with the tibia. That’s the case with Tupuxuara’s fibula. It’s fused to the tibia from the base, and gradually becomes thinner and thinner as it stretches along the length of the bone.

I started making the bone shafts curling them from 2mm sheets of XPS foam. It took me an hour to do this (I did find foam tubes for sale, but they were either too flexible or made of foam which was not dense enough, so I decided to roll the foam as usual).

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Then I used rubber bands to keep the gluing tube in place while I made some adjustments, curving the femur a bit, or widening the base of the tibia.

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I attached bits of thicker (3 cm) foam at the ends. When dry I carved the end shapes according to the pictures and and trimmed with a knife and with fire. As usual, I didn’t have views from the bone ends, so I had to do it all from the side views.

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The fibula is fused to the tibia, so I made it separately and attached it to the tibia before covering with resin.

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These are the tibiae (actually tibia-fibula pairs) and femora for both legs after all the foam work.

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After that I added a layer of acrylic resin, let dry for a day, then sanded and stained with coffee powder. This is the final result. Four views of the leg bones.

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Here are both bones connected (I am still not 100% sure about connections, so this might be wrong).

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And some images of the full skeleton with the leg bones (the unfinished pelvis is there temporarily to hold the femora in place.)

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Tupuxuara’s wing: the humerus, radius and ulna (final)

It took a couple of days to finish these bones since I had to carve many details and because the foam glue, when applied over a large surface, takes very long to dry (it’s risky to carve while it’s not completely dry). Now we only need the carpals to be able to assemble the wings.

DCF 1.0

I have no source photos of the bone ends, and it wasn’t very easy to discover their shape by just looking at the other photos. The humerus has a very complex end. I made some sketches, looked at pictures of humeri of other pterosaur species, and experimented a bit before attaching the ends. It was easy to close the shaft and the distal end of the humerus.



But it was challenging to sculpt the proximal end. After some trial and error, I had something like this to start working.


But then I still removed and added foam until I finally had a shape that matched the side views. After I finished one bone I used it as a reference, so the second humerus I made much faster.


Here are some pictures of the result showing four sides of the humerus. The pencil is 16 cm long. Both are approximately the same side. The angle the photo was taken may make one seem larger than the other in some views.





This is the distal end (the end that connects to the radio-ulna pair). It’s speculative (I invented it using the side views as a source).


And this is the proximal end, which connects to the shoulder (scapulacoracoid). It is also speculative. I might make adjustments later when connecting the bones.


Now the radio-ulna pair. I wasn’t able to trim the radio bone’s shaft to its correct width. The technique I used (see last post) was not a good one. So I tore the shafts apart, preserved the bone ends, and made new shafts by rolling thin (2 mm) foam. Here they are attached to the bone ends.


And now some photos of the final results. The bones are not yet connected. I just pinned them together for the photos.





These are the sides that fit together.


The proximal and distal views are speculative since I don’t have any photos of them. They were derived from the side views. This is the proximal end (which connects to the humerus).


And this is the distal end. (I’m not 100% sure that I am right. It may be the other way around. I’ll have to check that before assembly.)


Now we can assemble the wings. I still can’t connect the bones because the carpals (between the wing metacarpal and the radio-ulna pair) are still missing.


Here is a picture of Tupuxuara so far. I’m now working on the carpals, pelvis and leg bones.


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