Tag Archives: notarium

Tapejara’s dorsal vertebrae

Here is a picture of Tapejara compared to an unknown thalassodromid comparing skull and neck. 2013-07-16 12.45.53

But this post is about the vertebrae that come after the neck: the dorsal vertebrae. The first four to seven of these vertebrae is fused in most adult pterosaurs to support the pectoral girdle and is called the notarium. There is no fossil evidence that this occurred in Tapejaras, but none of the specimens used are considered “full grown adult” either (I’m referring to the ones that were published). Some decisions that affected the dorsals also involved the cervicals, so I might also talk a bit about them here.

I had some trouble with my sources. I used the same ones I had used for the cervicals, but several images published in the article about SMNK PAL 1137 had the wrong scales, so the sizes didn’t match. Not even the reconstructions using the bones from the same specimen matched, and the descriptions confused me more than they helped, so I had to rely on other sources. MN 6588-V has several dorsal vertebra but it’s not really a tapejara, and it also has an incompatible scale: if I match the size of the cervical vertebra in that specimen, all the others become too small.

2013-07-18 13.25.00

So I decided to trust the scale I was originally using (from IMCF 1061) which unfortunately has no dorsal vertebrae, and to estimate the size based on Tupuxuara. The problem is that Tupuxuara’s cervical vertebrae are proportionally shorter, and so is the pelvis, so maybe the Tapejara has a narrower and longer body than the Tupuxuara, or maybe it just has a proportionally longer neck. I don’t know.

I checked other reconstructions (drawings and sculptures), but they seem to either have fewer cervicals, or identical cervicals. I observed that both in Tupuxuara and Tapejara (Iwaki specimens) there are some longer cervicals and others which are shorter and taller. I am not sure about the order, but in the (unpublished) Iwaki specimen, they were numbered, and the two shorter ones were cervicals no. 3 and 5 (not counting Atlas/Axis). I don’t know how accurate that ordering is since there is no publication, but I assume they either knew before preparation or they fit somehow, and since that’s the best information I have, I followed that same order in Tapejara.

I decided to not use any reconstructions as sources except my own. I used the four dorsal vertebrae from SMNK PAL 1137 as sources ignoring their  (incorrect) scale, adding broken and missing parts, and tried to fit them with the eighth cervical vertebra, using the Tupuxuara notarium as a reference but making each vertebra a little wider. After trying out three different prototypes, I could finally start making a final version.

I used foam strips for the processes and thicker foam for the vertebra’s body.

2013-07-16 17.38.06 2013-07-16 17.43.09 2013-07-16 17.43.18

After fitting the processes together, I separated the vertebrae to add details (processes) to each one.

Here are some views of the vertebrae after molding with fire, but before adding modeling resin.

2013-07-16 18.54.44 2013-07-17 16.50.36 2013-07-17 16.50.48 2013-07-17 17.09.58

And here some more views after resin and staining with coffee.

2013-07-18 01.15.54 2013-07-18 13.01.35 2013-07-18 13.02.11 2013-07-18 13.02.28 2013-07-18 13.11.55 2013-07-18 13.20.54

These are the dorsals that are part of the pectoral girdle, and which will articulate with the scapula. The exact number of dorsals after them before the sacrum seems to be unknown. Most reconstructions draw six notarium vertebrae + three to four free ones + two to three pelvic dorsals before the sacrum (that means 5 – 7 more dorsals), but other authors mention 10, 12. It seems that there is not enough evidence to be sure. I am also not sure about their shape. Do they get smaller, narrower, wider?

I don’t mind reading dozens of publications. It’s great. They revealed that many of my assumptions were bad theories, but they usually don’t offer me a solution. They open a discussion. And so, the more I read, the harder it is to make decisions, and I also reach the point where paleontologists disagree. It’s a fantastic discussion, really, but I have a deadline, so I have to make some choices. If they are bad, I will try to fix it before I deliver the skeleton.

So I decided to make 9 more dorsals (a total of 15). Three will be fused to the pelvic girdle, and the other six will be free. This is a first 3D sketch (the body and the spine of six dorsals).

IMG_5352

After adding the processes and splitting.

IMG_5358

After acrylic resin and staining.

2013-07-25 16.49.18

They are not really finished: I’m using them as prototypes so I can continue the work. Later I might reshape them, cut some excess foam, make them thinner, narrower, or even throw them away and make new ones. For now they just need to be functional.

I’m trying to find reliable information to make the pelvis. The only sources I have are SMNK PAL 1137 (just pelvis, no sacrum, one or two views of each bone and no more), and a side view from MN 6588-V. I would be nice to have other views. I’ve been trying to obtain permission from the Iwaki museum so I can have access to all Tapejara photos (I only have some), but so far I haven’t received any response. I might have to continue without them, unfortunately.

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Tupuxuara’s shoulders: the scapulocoracoid

In humans, the bone that connects the scapula to the sternum is the clavicle. Most other vertebrates have coracoids connecting scapula to stern (although they may also have articulating clavicles). Humans, marsupials, and mammals that don’t lay eggs do not have coracoids (but they do have a small hook in the upper scapula which is called the coracoid process). Birds and pterosaurs which require a strong shoulder girdle to support the wings have the scapula and coracoid bones fused together. This bone is called the scapulocoracoid.

The Tupuxuara specimen at the Iwaki Museum in Japan has one well preserved scapulocoracoid (as far as I know: I only have the pictures), so I used it as a model for both left and right scapulocoracoids.

cut

My sources are only four views of the scapulocoracoid (two sides, inner and outer views). It would be best to have at least six, and some photos in different angles as well, but from these sources I could infer the shape of the bone to start making it and later make any necessary adjustments. From the outer and inner views it seems that the scapulocoracoid has the twisted shape below, when seen from the side that connects to the arm.

twist

The place where the two flat long bones are fused together is full of details which aren’t so easy to see from the photos. I cut out the general shape in thick foam using the side views as a reference.

connection

Then I cut it again (since the base is not flat), trimmed the parts so they would fit well and pasted it onto the scapulocoracoid shaped foam strip. The next step is to shape the coracoid and scapula bones. I started adding strips of foam (since I will make it hollow.)

foam1

I reinforced both long bones with a thin (3mm) somewhat flexible wooden stick inside, along the length of the bone. I didn’t photograph it. The photo below shows both scapulocoracoids almost finished.

foam2

This is the right scapulocoracoid just before finishing with fire.

right_foam

And this is the left scapulocoracoid after the fire sculpting.

left_foam

Here are both of them:

finished_foam

testing_foam

After that, I added a layer of acrylic resin (modelling paste) and tried to mount the pectoral girdle. But… which side is the coracoid and which side is the scapula? The part I thought was the coracoid seemed too short, so maybe it’s the other way around.

AorB

I lack experience in vertebrate anatomy, so I needed to do some research. I discovered that, unlike Guidraco, Anhanguera and other Ornitocheirids, Tupuxuara has a shorter coracoid (like Tapejara and Azhdarchids). In Anhanguera the shoulders would be placed near the back, where in Tupuxuara they should be closer to the front. The pictures above are not precise since I still had to adjust all the parts, but it seems that the correct placement is the second. The first assembly places the scapular bones almost perpendicular to the notarium (that’s why in ornitocheirids there sometimes is a depression on the the vertebra’s spinal process.) For the second one to work, the scapulas have to move back more and barely touch the spine at an angle (45 degrees or more). I am still not sure about all of this and will do more research before attempting to assemble it.

Here are the pictures of the finished scapulocoracoids.

back

bottom

front

top

Since this is a very complex bone to grasp from photos, it’s good to have views in other angles.

angle1

angle2

outside

I still can’t assemble the full pectoral girdle connecting the stern and notarium. I made the first vertebra too wide and will have to remove at least 1 cm from each side. But I was able to test the connection with the stern. Here are some pictures (I didn’t double check and don’t really know if this is the right way to do it, but it seems to fit nicely).

girdle_back

girdle_bottom

girdle_front

girdle_side

girdle_top

The two pieces below should fit together nicely, but they don’t because of a problem in the larger vertebra. I will have to fix that before assembling the pectoral girdle.

girdle_notarium

But I tried anyway (it’s made of foam, so I can always squish it a bit :)) The pectoral girdle will look something like this when finished:

neck_mount

head_mount

Tupuxuara now has shoulders. Now we need to connect some arms to them. Tomorrow we will make two humeri.

side_head

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Tupuxuara: thoracic vertebrae and the notarium, part 2

orphan_w_pterosaur

I finished the first two thoracic vertebrae, which completes the notarium. This is vertebra no. 2 before covering with arcylic resin.

v2_foam_detail

Here it is after the resin and coffee stains, in place with vertebra no. 1 which is still under construction.

v1_fit

I had a good frontal view of vertebra no. 1, since it is the first one in the notarium. Here I am working on the rib (which is hollow).

v1_3D_ribs

Vertebra no. 1 required a lot of work, and adjustments. These are views from the front and back before adding the layer of resin.

v1_foam_front

v1_foam_back

Here are views of the six thoracic vertebrae disconnected. This is the rear view.

all_back

And this is the front view.

all_front

I won’t permanently connect the bones yet. This is a dorsal view of the notarium:

notarium_dorsal

And a ventral view:

notarium_ventral

And here are some pictures of the notarium connected to the neck.

connected_dorsal

connected_side

connected_ventral

neck_and_thorax

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Tupuxuara: thoracic vertebrae and the notarium, part I

lab

I have six photos of the notarium: the six thoracic vertebrae fused together at the pterosaur’s back. I have no photos of the individual vertebrae, and since I want to have as much detail as possible I used other photos of other notariums and thoracic vertebrae as a reference. I also inferred vertebral shape by looking at the last cervical vertebrae of the Tupuxuara.

I started carving the notarium in one piece.

notarium_start

Then I started adding details on the sides with strips of foam.

flaps

After that, I separated the vertebrae.

split

The specimen I am using as a reference has no ribs on the last two thoracic vertebrae, but that doesn’t mean it did not actually have ribs. I might add them later. The photo that shows the notarium seen from behind reveals details of the last vertebra. So I worked on these two first.

last two

Then I started working on vertebrae three and four.

three and four

Here are some pictures of the unfinished notarium without any ribs.

testing

testing w cerv

Testing the connection to the rest of the spine:

testing_neck

And checking what it will look like when connected to the rest of the pterosaur.

testing_skull

It’s easier to add details to vertebrae 3 and 4 with the ribs in place. I made them hollow, using two halves of foam, and using smaller bits of foam to fill the gaps, add detail and strengthen its base. I then connected the notarium together to compare with the photos.

with four

Here are the last four thoracic vertebrae of the notarium seen from the back. I still need to fix some details.

four

Now I started working on the first and second vertebrae. This is part of vertebra no. 2.

number two

And here vertebra no. 2 with a bit more detail.

two

Now I can test the connection of the whole notarium.

bottom_ribs

side_ribs

top_ribs

The shape still does not match the photo. I have to do some twisting, cutting and reshaping before finishing. In the next post I will show the complete notarium.

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A new notarium

I remade some vertebrae, unassembled the scapulae and coracoid bones, and replaced the notarium with a new one. The old one was not robust enough. I also connected the vertebrae in the pelvis.

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Filed under Pterosaur #1: Guidraco