Tag Archives: cervicals

Tapejara: improvements and fixes

All the bones are finished. Time to add a protective resin layer and to make some small fixes. Here are some of them drying after receiving a layer of epoxy.

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All the bones already have a resin layer except for the cervicals, anterior part of the skull and the scapula-coracoid pairs. I have to improve them using the images from IMCF 1061 which I received. They are simple fixes and not as complex as the neurocranium.

The easiest is the scapula-coracoid pair. I had to discover how to connect them before hardening (when they only have an acrylic polymer layer they can still be twisted, heated, and slightly reshaped.) So I did some research and finally discovered how the coracoid and scapula should articulate.

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The skull needed reinforcements on the inside, lacrimal and post-orbital bones. I didn’t find fossil evidence in Tapejaras for the large triangular cavity in the posterior part of the palate, so I closed it (it seems there might be a small one, but I’m not sure). I had based the palate on other thalassodromid specimens, since the IMCF 1061 palate seems to be missing.

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This is the skull before adding the missing bones.

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And after

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Here are some pictures of the nine parts of the skull attached. The neurocranium and quadrates were attached to the rest with silicone rubber (they can be easily detached). The mandible joint was also made from “cartilage” of silicone rubber. It firmly keeps the mandible attached to the quadrate, but allows some flexibility (so the Tapejara’s beak can hang open).

final1 final2 final3 final4

My cervicals had posterior condyles which were too short and they all had missing anterior cotyles. Here is a picture of the vertebrae when I had “finished” them. The black lines show what is missing:

cervical rod

My first sources were very bad. I had to rely entirely on black and white photos from the SMNK PAL 1137 article, and I didn’t see the cotyles there. But then I received the pictures from IMCF 1061 and fixed the vertebrae, adding pieces of foam to form a small ridge under each vertebrae (or the cotyle), and three small tubes behind (for the longer postexapophyses and condyle). I forgot to photograph them while I was making the fixes. Here are some pictures showing the final result.

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cv1

cvstop

There are obviously many other details which can be improved. Since my sources are only photographs, and usually bad ones, I do what I can. The IMCF 1061 photos were great because they allowed me to see more details and improve the replica.

 

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Tapejara cervical vertebrae

with neck 1

I got a bit behind schedule this week with some other projects but I was able to recover half of the time this weekend and get the cervicals done. Now Tapejara has a neck, as shown in the picture above.

I started gathering all the data I had which included cervicals from 4 different specimens. The SMNK specimen is smaller than the others. I used the IMCF specimen as a reference, double checked by comparing the size of the cervical vertebra in the AMNH specimen. I also used Tupuxuara vertebrae (from IMCF 1052) scaled to the same size as the Tapejara because of its better resolution and because it has a complete collection. But the IMCF, SMNK and AMNH vertebrae are all proportionally a bit longer and narrower than the Tupuxuara vertebrae, so I made considered that as well. Here I placed all of them in scale.

research_no_IMCF

I started with some prototyping and made hollow cervicals (as I did before with Tupuxuara). This time I used 2mm XPS foam (instead of the 5mm foam I used in Tupuxuara) since the Tapejara vertebrae are less than half the size of Tupuxuara vertebrae.

prototype 1 prototype 2

After assembling, gluing, shaping, adding texture and molding with a lighter, we have a prototyped vertebra.

prototype 3

From those prototypes, I cut out the foam in this pattern for vertebrae 1, 2 and 4 (3 and 5 have a slightly different shape, a bit taller and shorter).

final prototype

Here are the five vertebrae, after assembly and shaping with a lighter.

cervical rod

After finishing all 8 (or 9 if the fused Axis/Atlas are considered 2), I made a spinal cavity in each one, and crossed it with a wooden skewer. Here is the Tapejara with a stiff neck.

stiff neck

As I did with Tupuxuara, I used a rubber tube (4mm diameter) as a spinal cord.

medulla

Here are the Axis/Atlas and seven other cervical vertebrae connected with the tubular medulla.

cervicals connected

The last two vertebrae are slightly shorter.

last cervicals

The neck is assembled connecting the vertebrae. It retains some flexibility (less to the sides, more up or down).

neck

And finally the Tapejara with the neck in place. It’s still not possible to attach it, since the skull still lacks several posterior bones.

curved neck

Tomorrow Tapejara will have some thoracic dorsal vertebrae.

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