Somewhat fishy

[Mahnmut]

Its hatched!

[pachy-pleuro-whatnot-odon]

32 minutes ago, Mahnmut said:

Its hatched!

 

Wow! Even disassembled like this it already looks super cool! Can't wait for the final result!

[IsaacTheFossilMan]

Wowee! That's beautiful!

[Mahnmut]

Thanks!

If you liked the last pic, look at the next!

It is strange, I took a 2d drawing of a 2.5d preserved fossil to build a digital 3d model to have it printed and take a photo to show you here in 2d again. Still i like the foto of the model better than the 3d previews above.

The base is something I made for the triassic fossil branch my Megaladapis is sitting on that I did not use.

Aloha,

J

 

[pachy-pleuro-whatnot-odon]

1 hour ago, Mahnmut said:

Thanks!

If you liked the last pic, look at the next!

It is strange, I took a 2d drawing of a 2.5d preserved fossil to build a digital 3d model to have it printed and take a photo to show you here in 2d again. Still i like the foto of the model better than the 3d previews above.

The base is something I made for the triassic fossil branch my Megaladapis is sitting on that I did not use.

Aloha,

J

 

 

That looks pretty awesome! Did you apply any paint? Not sure whether it's the light or paint, hence my asking. But I think the result came out really good! Well done!

[Mahnmut]

Thanks!

yes, I slightly coloured it. The original printed colour is snow white, it makes it difficult to see the details. I pondered to give the model a realistic dark fossil colour, but that would also  make it less discernible. So I settled for a "modern bone" colour for now.

[pachy-pleuro-whatnot-odon]

20 minutes ago, Mahnmut said:

Thanks!

yes, I slightly coloured it. The original printed colour is snow white, it makes it difficult to see the details. I pondered to give the model a realistic dark fossil colour, but that would also  make it less discernible. So I settled for a "modern bone" colour for now.

 

What kind of paints did you use for it? Acrylic, oil, water...?

[Mahnmut]

Acrylic, highly diluted in water. Applied with a soft brush. I mostly use 3 colours, black, burned umber and "sand". They work well to mix many "mineral" hues.

My "modern bone" look is just a hint of "sand" on white. I dilute the acrylic until it is liquid like water and let it wet the model, it flows into the recesses. then with a dry soft brush I take away the excess liquid. The fragile parts of the model would not take more pastose paint well.

Best Regards,

J

[pachy-pleuro-whatnot-odon]

8 minutes ago, Mahnmut said:

Acrylic, highly diluted in water. Applied with a soft brush. I mostly use 3 colours, black, burned umber and "sand". They work well to mix many "mineral" hues.

My "modern bone" look is just a hint of "sand" on white. I dilute the acrylic until it is liquid like water and let it wet the model, it flows into the recesses. then with a dry soft brush I take away the excess liquid. The fragile parts of the model would not take more pastose paint well.

Best Regards,

J

 

Thanks! That would've been my guess, as to method. But I'm not a model builder, so it's very interesting to read your procedure. Anyway, it's indeed a very nice effect!

[IsaacTheFossilMan]

Wowee, that's gorgeous! And that paint is very well done, awesome, awesome job!

[Mahnmut]

Ahoi,

I have been tinkering with Helveticosaurus again.

I know the preservation makes a confident reconstruction impossible. After trying for some time to build in 3d the only skeletal reconstruction I could find online, I decided that it appears somewhat fishy. So I began to try my own reconstruction based on the 1974 holotype drawing by Kuhn-Schnyder. In that fossil it is indeed not easy to separate taphonomy from anatomy.

Here is my humble beginning.

Aloha,

J

[pachy-pleuro-whatnot-odon]

55 minutes ago, Mahnmut said:

Ahoi,

I have been tinkering with Helveticosaurus again.

I know the preservation makes a confident reconstruction impossible. After trying for some time to build in 3d the only skeletal reconstruction I could find online, I decided that it appears somewhat fishy. So I began to try my own reconstruction based on the 1974 holotype drawing by Kuhn-Schnyder. In that fossil it is indeed not easy to separate taphonomy from anatomy.

Here is my humble beginning.

Aloha,

J

 

That's quite some progress you've made there already, Jan! Figuring out which bones belong to which part of the body from that drawing can't be an easy task. It's also interesting to see your process of first colouring the bones by class, and then cutting the skeleton up into sections (as top and bottom skeletons concern the same specimen - something that wasn't immediately obvious to me). It'll be interesting to see where this takes you.

 

Let me know whether you could use another photograph of the holotype specimen other than the one from Wikipedia, reproduced below. It's not a high quality photograph, unfortunately, due to reflections on the glass and my wife not having warned me we would be visiting this museum when she surprised me with this trip (hence, didn't bring my D-SLR and polarizing filter), but it's taken from the other direction and might show some details not visible the Wikipedia-version.

 

[IsaacTheFossilMan]

3 hours ago, Mahnmut said:

Ahoi,

I have been tinkering with Helveticosaurus again.

I know the preservation makes a confident reconstruction impossible. After trying for some time to build in 3d the only skeletal reconstruction I could find online, I decided that it appears somewhat fishy. So I began to try my own reconstruction based on the 1974 holotype drawing by Kuhn-Schnyder. In that fossil it is indeed not easy to separate taphonomy from anatomy.

Here is my humble beginning.

Aloha,

J

Very interesting, you have quite a knack for this! I can imagine how hard it'd be working off of that drawing! Fascinated by your ever-talentedness! 

[Mahnmut]

Thanks Alexander and Isaac!

Photoshop is my friend here. The skull will be the real challenge. I am not assuming that my reconstruction will be better than the one already online, but it will be mine, and maybe it will not be much worse. That site that calls itself heretic has nice looking drawings, but you never know what agenda it has. I do not make many assumptions concerning cladistics (except this being a marine reptile sensu lato), I just try to fit the sizes of the fragments I see into a plausible shape.

At the moment I am "working" with the drawing by Kuhn-Schnyder (is that one person or two?), but another photograph may help at a later stage.

By the way, you can answer without quoting the whole entries, it keeps the thread shorter.

Cheers,

J

 

[IsaacTheFossilMan]

You're very welcome!

Emil Kuhn-Schnyder is one person

[thorst]

That assembled and painted print looks amazing! Congratulations for such a wonderful result!

[Mahnmut]

Ahoi.

I think my reconstruction of Helveticosaurus takes shape. In the fossil (drawing above), there are ribs toward the lumbal region that seem to have about 90 degrees of curvature. In the "heretic" reconstruction, these are showing with all of that curvature visible in the lateral view. I am not sure about the convention for skeletal drawings (being discussed a lot lately concerning foreshortening of Spinosaurus leg bones). But as far as I understood it, ribs in contrast are not usually drawn in their least foreshortened position, or are they?

My assumption is that most of this curvature in vivo happened in the coronal plane, not the sagittal, before being flattened into the fossils near coronal plane. I also assume that there was not a great amount of plastic deformation of the bones and the ribs lay flat before breaking and thus loosing the rest of curvature.

Any thoughts on that?

Aloha,

J

 

[pachy-pleuro-whatnot-odon]

Sorry, can't help you with that, as I know nothing about reconstructive drawing...

[IsaacTheFossilMan]

Also cannot help you, but super excited to see what you've been cooking up...

[Mahnmut]

Hi @IsaacTheFossilMan

thanks for your interest!

I did not proceed much on Helveticosaurus since my last post. The postcranium looks quite like your genuine  generic marine reptile when corrected for what I see as a distorted reconstruction of the ribs, while the skull is pretty much guesswork based on the teeth, as the only fossil is so heavily crushed.

But here is how far I got.

Aloha,

J

 

Edited September 18, 2021 by Mahnmut
vocabulary

[IsaacTheFossilMan]

11 hours ago, Mahnmut said:

Hi @IsaacTheFossilMan

thanks for your interest!

I did not proceed much on Helveticosaurus since my last post. The postcranium looks quite like your genuine  generic marine reptile when corrected for what I see as a distorted reconstruction of the ribs, while the skull is pretty much guesswork based on the teeth, as the only fossil is so heavily crushed.

But here is how far I got.

Aloha,

J

 

 

That's fair enough! It's good enough to fool most of us

 

Awesome work as always mate; glad to see you continuing the thread!

[Mahnmut]

Ahoi,

I am back into the water.

Helveticosaurus will have to wait, its just to much guesswork.

Once again I ask myself which reconstruction to trust more.

For Eretmorhipis I have two sources, one very close to the fossil by Cheng et al.:

https://en.wikipedia.org/wiki/Eretmorhipis#/media/File:Eretmorhipis_complete.jpg

That one looks as if this strangely armored animal was relatively unflexible dorsolaterally -ventrally.

On the other hand there is this beautiful drawing by Jaime A. Headden, who gives it a nice dynamic curve.

https://qilong.wordpress.com/2021/08/20/how-am-i-even-supposed-to-say-this-name/

 

What do you think?

How flexible was that fantastic beast?

Best Regards,

J

 

 

Edited October 19, 2021 by Mahnmut
re-orientation

[Mahnmut]

Ok, here is some more info:

https://www.researchgate.net/figure/Whole-views-of-the-two-specimens-of-Eretmorhipis-carrolldongi-gen-et-sp-nov-A-the_fig7_277411141

That downturned tail may still be taphonomy, but the white specimen makes the curved version more plausible in my eyes.

Aloha

J

 

[pachy-pleuro-whatnot-odon]

On 10/19/2021 at 1:07 PM, Mahnmut said:

What do you think?

How flexible was that fantastic beast?

 

Hard to say, to be honest, as taphonomy can be very misleading. Not only can it move entire body parts, as you've seen with Helveticosaurus,, but it can also create twists and turns were none were to begin with - such as in the Dinosaur Death Pose (although following the text here - also the source of the image below - the Death Pose itself has not been reported for ectothermic organisms, thus may not apply here, even if the principle does).

 

 

What's more, a tail that turns down at that position in the body has significant implications for the animal's locomotion, which will be in the vertical plane, rather than the horizontal one (think up-and-down wave motion, rather than something like anguilliform or carangiform). Movement in the vertical plane is not typical for marine reptiles, with the only marine species known to have exhibited such locomotion being mammals (see here for a related discussion pertaining to plesiosaurs). I'd therefore be rather weary of concluding the tail was bent down as a result of locomotive action, rather than taphonomical causes. To properly determine whether or not the Eretmorphis moved in the vertical or horizontal plane, you'd closely need to study its vertebrae, which would also tell you how much degree of motion the tail had, and may be even if the animal had a tail fin or fluke. The typical way such conclusions are reached has to do with shape of the vertebral centrum - if wedge-shape this may indicate a bend in the tail, and broader than tall may indicate up-and-down motion, whereas taller than wide indicates sideways motion - and thickness, inclination and length of the spinous process. As none of these features can be properly studied from the photographs you have available, I'd again be careful to conclude locomotion in the vertical plane.

 

However, do keep in mind that to maintain proper tension on the spine and not exert overly high tensions, a spine will typically have a slight S-curve. This by no means implies a down-turned tail, but finding a slight declination in that general area wouldn't be entirely surprising (compare with plesiosaurs or sirenians, for example). Also, depending on the density of the bones and how these work in overcoming the problem of buoyancy secondarily aquatic animals face, Eretmorphis may have needed either a slightly upward or downward directed tail to exert a minimum amount of thrust in the opposite direction while moving forward. Thus, looking at bone density for Eretmorphis may also provide you with hints on whether a downturned tail would be likely or not.

[Mahnmut]

Thanks once again Alexander for your insight into marine reptiles.

There is nothing in what you stated that I could argue.

Although I o not know the lateral thickness of the  thoracal vertebrae in any of the specimens, their great height and little length do not speak of great flexibility in a vertical plane. Its not typical for marine non- mammals either, I know.

But as I am not looking for the anatomically neutral position in my models, but for an interesting pose that the animal could have plausibly taken in life, I tend to accept the downturned tail as plausible, even if the drawing by cheng et al  is much closer to anatomicaly neutral.

I was really surprised when playing around with a 3d print of a hero shrew spine recently. Even the interlocking centra that are more than thrice  broader than long do provide the animal some lateral flexibility.

Well,  do not know.

Cheers,

J

Edited October 22, 2021 by Mahnmut
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