spinosaurus reconstruction

[jnoun11]

hi guys

problem with metatarsals

on a picture from the publication we have the right pes, where two metatarsals are cast,metatarsalsl 3 and 4.

the positions of metatarsals 1,2,3 are ok.

now i have a doubt about the connection between metatarsal 4 and 3.

the original metatarsal 4 is supposed to be left one,and the mirror copy is a 3D print inverses.

in brown we have the original cast from originals bones,on white the 3D copy.

when i make the position like on a pictures 1,2,5 that feet good.

but if i want respected the picture on publication , like the picture 6 and 7, the pulley is not in axis of the pulley of metatarsals 2 and 3.

what is for you the best position and did you have some pictures or arguments?

[Troodon]

I believe the proximal end should look like photo #5.   I do not like the distal end of IV in photo 1 looks flat.

 

Here is metatarsal IV from my collection

 

 

 

[MBL13]

It should be as in 5,the original is missing the IV metatarsal,that explains the discrepancies.

I think Ibrahim et al. reported three new metatarsals for the neotype last year.

[kingspino]

I would also go for pic 5, I took this image from Allosaurus : a revised osteology notice the way the tarsals are articulated in proximal view, that is the way it is supposed to go or at least the common way they are articulated. Adding to MBL13, Ibrahim et. al. 2020 did report new foot material i believe jnoun11 has all the bones based on the image he posted. Finally Troodons "metatarsal" is nice but i don't believe it is Spinosaurus or dinosaurian i think based on its anatomy it is more likely crocodilian, perhaps even a metacarpal based on its stockiness. The discrepancy is mainly because their reconstruction comes fro the 2014 paper which was prior to the discovery of the new material the metatarsals 3 and 4 were probably reconstructed from other taxa so i wouldn't worry about the difference.

 

[MBL13]

Image above shows the Mts III,which should be labelled as known,rather than a reconstruction.

Strangely,the proportions match the one above.It might indicate that the Mts III is from the other side.

This bone,along other two metatarsals,can bee seen in the figure below:

[jnoun11]

thanks guy s for the precious help. now the rear limbs are corrected and the front limbs are on a way. next step the ribs cage and gastralia....

[jnoun11]

hi

now i m working on a skull, i catch some cast from america ,composed by multiple pieces.

i have a little problem with the place of the quadrate. like it was on picture 2 the quadrate didnt touch the quadratojugal,and live an opening spot beetween quadrate and basioccipital.

i have 3D printed the quadrate and i have the intuition, the quadrate must be placed touching the quadratojugal and the "basisphenoid" for closing the skull, like picture one.

in this configuration ,the skull and the jaws are perfectly aligned, not like picture 2. did somebody have some ideas about the form of the spinosaurus jugal, i suspected its relativly flat bones and the back of the skull must be more slender. whats your opinion, everybody idea is welcome.

[LordTrilobite]

The quadrate should touch the exoccipital, the squamosal and the quadratojugal. It should not touch the basisphenoid.

[jnoun11]

8 hours ago, LordTrilobite said:

The quadrate should touch the exoccipital, the squamosal and the quadratojugal. It should not touch the basisphenoid.

hi lordtrilobite

so i will modifying the back of my skull for make him more slender so the quadrate will touch the exoccipital ,the squamosal and the quadratojugal, ans also makng the lower jaws more slender, more straight.

thanks for the help.

[MBL13]

I would also take into account allometry,as juvenile rostra and dentaries are thinner compared to adults.

Also, could you provide better imagen from behind?

[kingspino]

I know i'm bit late, but yeah the quadrate is definitely displaced you can see the pterygoid flange is pointing towards the brain case when it is supposed to be inclined further to the front attached to the palatal bones. MBL 13 does make an excellent point, i would expect to see some differences in ontogeny, if you look at MSNM V 4047 it is estimated to come from 15 m animal compared to 11 m in the neotype and holotype so the former would be a much larger and heavier animal therefore with a skull probably more robustly built. Described skull fossils do indicate allometry but they are very scrappy so it is hard to tell. 

Oh by the way Jnoun you mentioned it's a composite, you'r not referring to this skull right? I know it flopped at an auction in 2009 at Druout then it resurfaced as FPDM-V7011 in the Fukui prefectural dinosaur museum. i know it might not be from it but it would have a great reference for your reconstruction.

[LordTrilobite]

14 hours ago, kingspino said:

I know i'm bit late, but yeah the quadrate is definitely displaced you can see the pterygoid flange is pointing towards the brain case when it is supposed to be inclined further to the front attached to the palatal bones. MBL 13 does make an excellent point, i would expect to see some differences in ontogeny, if you look at MSNM V 4047 it is estimated to come from 15 m animal compared to 11 m in the neotype and holotype so the former would be a much larger and heavier animal therefore with a skull probably more robustly built. Described skull fossils do indicate allometry but they are very scrappy so it is hard to tell. 

Oh by the way Jnoun you mentioned it's a composite, you'r not referring to this skull right? I know it flopped at an auction in 2009 at Druout then it resurfaced as FPDM-V7011 in the Fukui prefectural dinosaur museum. i know it might not be from it but it would have a great reference for your reconstruction.

It's not great reference tho. Perhaps for the preserved areas. But some parts are completely incorrectly constructed. The whole lacrimal is just wrong in every way and attached in the wrong place to the jugal. I've made an edit of that drawing, fixing some of the issues. But it's still not great as it's a composite and especially the lower jaw doesn't seem to fit well with the rest of the skull.

Tyler Keillor's skull reconstruction would be a much better reference. It's probably still the best at the moment.

 

And I don't think we know a whole lot about the ontogeny of spinosaur skulls yet.

[MBL13]

1 hour ago, LordTrilobite said:

It's not great reference tho. Perhaps for the preserved areas. But some parts are completely incorrectly constructed. The whole lacrimal is just wrong in every way and attached in the wrong place to the jugal. I've made an edit of that drawing, fixing some of the issues. But it's still not great as it's a composite and especially the lower jaw doesn't seem to fit well with the rest of the skull.

I've been working on this same specimen for a few days,as you mention,it's a bad composite.I decided to edit the skull entirely.

Rather than sticking with the shape of the rostrum,I looked at the image of the actual skull and extracted all bone fragments with different texture and color.

Although tentative,giving the limited data,I produce a somewhat different model.The mandible fits better than in your model, I'm not sure why.

The skull is not the best,so take it with a grain of salt.

 

Edited September 5, 2021 by MBL13

[LordTrilobite]

That already looks better than the "original". And good to see the jaw fits a lot better.

But I would change the back of the lacrimal.

 

Irritator is probably the best example of how the lacrimal should contact with the jugal.

Baryonyx also has a pretty good lacrimal.

[MBL13]

You are right,although I wouldn't extend it that much,here's a image showing a new shape(the old one in is red).I think I also need to modify other aspects of the image,I'll be using the neotype skull material to produce a better overall shape.

[LordTrilobite]

Nice.

[kingspino]

Well yes the skull does have it's problems i have also been working on it for some time the main thing is that it's posterior is not articulated correctly if you notice the quadrates are completely dis articulated the jaw Lordtrilobite said is off due to bad reconstruction. the post orbital is a bit too inclined to the anterior if i'd say the squamosal should also be slightly lower to match the otoccipital, the skull roof doesn't look too bad to me i would not change but it does lack pre-frontals. the jugal would also be rotated slightly as the quadrates and quadratojugals would be rearranged to their position the lacrimal as again Lordtrilobite said is just wrong so i fixed that as well. In general the individual bones do match in terms of proportions with the types so perhaps in that respect this skull does deserve more digging into but is just my opinion. I do agree with trilobite in his affermation on Tyler keillors skull great artist by the way but perhaps in terms of certain parts like the braincase i would have gone for irritator as reference for reconstruction as it is a much more closely related taxon to spinosaurus than suchomimus the taxon which Ibrahim et.al. 2014 used for there initial reconstruction, also note that since then more skull bones have been attributed to spinosaurus so their skull is not as accurate as you might think, aesthetically pleasing but not as accurate as it should be that is my view of it. Anyway this is my own reconstruction based on the elements that are real fossil with the right squamosal reversed to the left. So when i said good reference i was referring to the preserved material as it is pretty much complete, but the reconstruction that was awful. My bad just a misunderstanding.

[MBL13]

I have here to mention a particular detail of that skull: Some random fragments have been included on it,we should be cautious as some material cannot even be identified as spinosaurid,.For example, the elongated bone shaft of the jaw,the lacrimal or squamosal lack either enough details to tell or don't show similarities with other spinosaurids. They shouldn't be used,something I reflected below.I also made edits to maxilla inclination,preventing image distortions.

 

 

 

Edited September 6, 2021 by MBL13

[kingspino]

Indeed, I agree there isn't enough comparable material and some material is a bit sketchy. For example look at my drawing the lacrimal looks almost out of place while the other bones like squamosal could be placed(i , uh, it does seem to fit to me) but the former the lacrimal i still couldn't do much with it. Lets also not forget that we are only viewing it from photos and not first hand we have no idea of where it came or this is indeed a single specimen so you said, therefore your idea that some bones may not even be spinosaurid is called for. My approach now is to base a reconstruction on the skull bones from the types, and then use this material to fill in the gaps. By comparing in more detail and observing certain details of the bones will only tell if we are right or wrong then again we are paleontologists so this is just our own unpopular opinion.

 

[jnoun11]

the project in process, i have included the parts like the nasal crest,or the squamosal

[jnoun11]

[jnoun11]

[MBL13]

I'm not sure the posterior skull should be positioned that way. Other spinosaurids have a reclined ventroposterior margin of the skull,so the jugal projects ventrally,not forming a continuous margin.

Look at the skull by Ibrahim et al.,the dorsal margin of the premaxilla forms a straight line with the nasals until the frontal.

In you reconstruction it follows an "L" in profile. This configuration is not present in any theropod I know of,where the anterodorsal margin of the skull is either arched or almost straight.

 

[LordTrilobite]

1 hour ago, jnoun11 said:

 

 

Oh you're basing it on this skull with the upturned snout? I'm not sure I would do that. It looks very wrong in many aspects. Are these direct scans you're using from the skull and then editing them? And is it known how much of this skull is real bone and what is filled in? I'm assuming it's a composite since it looks so bizarre.

Also I think that the frontal and postorbitals look more like those of a Baryonychine than a Spinosaurine. It doesn't look at all like the other skull elements from the Kem Kem beds.

The frontal doesn't seem to contribute to the orbit at all, or very little. This is a condition that is seen in Baryonychines like Baryonyx, Suchomimus, Ceratosuchops and Riparovenator. But this is not the case in Irritator and the other isolated Kem Kem frontal bones. There, the frontal contributes a great deal to the orbit.

And like MBL13 said, the snout shouldn't be that upturned. The lower curve of the antorbital fenestra also shouldn't be that curved. The lacrimal should extend further and be almost completely straight, instead of curved. The big muscle attachment for the neck and jaws on the top of the skull are also missing. The suture on the supraoccitpital is also not correct. The squamosals shouldn't extend that far over it.

And if that crest has the widening at the posterior base, that wouldn't fit with the other composite skulls either. In Baryonyx the crest goes all the way up end of the nasal to the suture of the frontal where the base of the crest is widened. But in the other Kem Kem composite skull this is not the case. The crest ends well before the end of the nasal and there is no widening of the crest base. It's still unclear how much of this crest is real. But it does seem like the crestless posterior part of the nasal is original. Which would make it distinct from Baryonychines.

 

 

I made a quick edit of the one photo. This is probably more what it should look like. I've rotated the rostrum and scaled the jaw down a bit.

[jnoun11]

hi guy s

i understand all your proposal and i will take all in consideration.

nobody want coming visiting me? i pay the plane ticket and food and roof.( not in first classe , i didnt have the money for that)

but that will be the best way to ameliorate the anatomy.

also did someone have a picture of jugal,post orbitofrontal or lacrymal from the kem kem beds?

for the moment i was thinking ,build my specimen like it is,and exhibit it at the tucson show, meet the theropods specialist and speacking with them and back to morocco i will make all modifications of the skeleton.

for the nasal crest ,the university of ain schock own one original on their collection and its massive at the base.