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LordTrilobite

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So I bought this piece on the internet...

 

It was advertised as a croc limb from Kem Kem. Except it wasn't a croc limb. Upon closer inspection of the images, I figured this was a theropod quadrate bone instead of a croc limb.

 

So now that it has arrived and I could get a proper look. I've come to the conclusion that I bought a part of a huge Spinosaurid skull. It doesn't look anything like the quadrates of Abelisaurs and Allosauroids, while it does show close similarities with those of Spinosaurids.

 

It's a right-hand quadrate bone that is almost complete with an articulated quadratojugal fragment attached to the side. It's huge and must have come from a skull of well over a metre long. Articulated fossils from Kem Kem are really rare.

And better yet, since I bought this as a croc limb, it was only like 60 euros.

 

 

So needles to say, I'm quite happy with my accuisition. This will be a fun one to clean.

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spino_quadrate05.jpg

Olof Moleman AKA Lord Trilobite

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Congrats! 

I would have been more impressed with croc, as I have a deep appreciation for them, but I understand Spinosaur material is more commonly prized :P

"Let us therefore follow after the things which make for peace, and things wherewith one may edify another."
-Romans 14:19

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22 minutes ago, Jesuslover340 said:

Congrats! 

I would have been more impressed with croc, as I have a deep appreciation for them, but I understand Spinosaur material is more commonly prized :P

Well, I have some associated skull bones of a croc just as large (Elosuchus) from Kem Kem as well. Those pieces also include a quadrate as well as a part of the maxilla, premaxilla, nasal and a cervical rib.

Olof Moleman AKA Lord Trilobite

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Just now, LordTrilobite said:

Well, I have some associated skull bones of a croc just as large (Elosuchus) from Kem Kem as well. Those pieces also include a quadrate as well as a part of the maxilla, premaxilla, nasal and a cervical rib.

I think I recall seeing them...were they on the crocodile and turtle thread?

"Let us therefore follow after the things which make for peace, and things wherewith one may edify another."
-Romans 14:19

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3 minutes ago, LordTrilobite said:

Yes, they were.

They were nice :) One day I'll get around to African crocodiles; focused on ziphodonts at the moment :)

"Let us therefore follow after the things which make for peace, and things wherewith one may edify another."
-Romans 14:19

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Nice! Good thing it fell into the hands of someone who knew what it was!

“...whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been and are being evolved.” ~ Charles Darwin

Happy hunting,

Mason

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4 hours ago, Haravex said:

Beautiful find and identification LT and I assume you will be posting some nice close up's at some point :ighappy:

Oh yes. I'm prepping it now as there is still a lot of junk on there. While the bone is slightly crushed, the preservation is really great and it has some fanastic details. I also found some micro fossils in the matrix that was wedged in the quadrate foramen. Among some random bone fragments that might be from the actual quadrate there was a fish scale as well as a bony plate fragment, might be turtle.

 

But when I'm a bit further with prepping or when I'm finished I will definitely post more photos.

Olof Moleman AKA Lord Trilobite

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I did a bit of prep work, so here are some progress photos. It's starting to look quite pretty as the preservation is really good. Though there is also some crushing. Mainly what's left of the quadratojugal has had some lateral crushing going on as it's partially rammed into the front of the quadrate, while on the back it doesn't even make contact with the quadrate anymore. There's also an area on the back that looks like an abnormal muscle attachment. A pathology maybe? While much of the prepping is going really well, the condyle on the bottom is really fragile so it's unlikely that I will be able to remove all of the iron concretion on there.

spino_quadrate09.thumb.jpg.4b4253a43f1b9d3104e61a9a65cea472.jpgspino_quadrate06.thumb.jpg.4669af15396aa545756c1ee4757b2206.jpgspino_quadrate07.thumb.jpg.15089cec5666fa7e0dae8d3659c11424.jpgspino_quadrate08.thumb.jpg.b7a5375e9ce8944591a0feacb32febd3.jpgspino_quadrate10.thumb.jpg.eca9b1a2fe192b11f4788bf436a385b1.jpgspino_quadrate11.thumb.jpg.2501fa3924403ab7413ba65ca2c19183.jpg

 

 

I also should have added this in the original post, but here is a reference image that shows how the quadrate fits into the skull. My specimen is from the right-hand side.

journal.pone.0144695.g002

Olof Moleman AKA Lord Trilobite

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Thanks, there's still some junk on there that I need to remove. It's just the condyle that I need to be careful with and probably leave some of the matrix on. When I'm done I will likely try to scan it as well so I can make a digital reconstruction.

Olof Moleman AKA Lord Trilobite

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I found an interesting video that's pretty relevant to this. Christophe Hendrickx, one of the authors of the paper Morphofunctional Analysis of the Quadrate of Spinosauridae (Dinosauria: Theropoda) and the Presence of Spinosaurus and a Second Spinosaurine Taxon in the Cenomanian of North Africa. talks a little about what they were able to discover about the quadrate bones of Spinosaurus.

 

 

 

Olof Moleman AKA Lord Trilobite

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  • 1 month later...

Well, I bought another one.

 

I found this piece on our favourite auction site. Sold as an unidentified dinosaur limb bone. Having a Spinosaur quadrate already I immediately recognised this as another Theropod quadrate with some clear similarities to my Spinosaur quadrate. I'm pretty sure this also is a Spinosaur quadrate. There are some small differences and it's slightly smaller and more slender. But many details and the overall shape is the same and consistent with Spinosaur quadrate morphotype 1, which is labeled as Spinosaurus aegyptiacus in Hendrickx's paper. Some of the differences in the paper are explained as being ontogenetic. My two quadrate bones seem consistent with this. If so, I'm thinking both are likely young adult specimens of large but not huge size (for Spinosaurus).

 

Dispite the differences, both specimens are clearly different from the morphotype 2 as described in the paper, which is labeled as Sigilmassasaurus. These are both very similar to morphotype 1. But the differences make me wonder if it might be more than ontogenetic, and if there might be sexual dimorphism as well. Does anyone know of any sexual dimorphism in theropod skulls?

spino_quadrate01.thumb.jpg.f955362ab4a81635cd257bd07fff8abb.jpgspino_quadrate03.thumb.jpg.48f61140e4e4b38ccd41f056ae634876.jpgspino_quadrate04.thumb.jpg.fe6fa04a57a70aed05bb03e54a9a1e37.jpg

Olof Moleman AKA Lord Trilobite

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Thats a great pickup.  Yep the big quandary in all these discussions is what we are seeing due to ontogenetic or sexual dimorphism differences or a new taxon.  Hendrickx's needs more specimens and he should be looking at eBay to help his research.  Now you need to acquire other elements and build a skull.  Nice acquisition.

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Thanks

Have you read the paper on the Spinosaur quadrates? Hendrickx actually did go into ontogenetic changes that seemed to be occuring as he sampled 5 quadrates that he attributed to a single morphotype, with a sixth quadrate he attributed to a second morphotype. Having read it I can see that my specimens show some similar changes when going from small to large. Dispite the differences I've compared these to Allosaurids, Carcharodontosaurids and Abelisaurids and these two bones look nothing like those. The only thing that comes close is Spinosaur morphotype 1 from Hendrickx's paper.

 

And I don't think I'll be able to make a composite skull any time soon :ighappy:. I got these two on the cheap as they were both misidentified as limb bones. But other material that is identified as skull is generally rediculously expensive. It seems like this might be a pattern, so I'd suggest keeping an eye out for "limb" bones that seem out of place incase they might be more skull bones.

But I will be scanning both of these bones and mirroring them to get a better picture of the size of the skulls these animals belonged to. I did a rough estimate of the first quadrate and I'm thinking that it had a skull of roughly 70 cm or 2.3 feet. The new quadrate bone is a few centimeters smaller as well as much more slender. I will likely make digital reconstructions of these to go along with the scans, so I will make better size estimates at that time.

Olof Moleman AKA Lord Trilobite

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Hendrickx paper was very interesting and will be looking foward to your 3D images to see the comparison..  What I find fascinating with all these papers is where they acquire their specimens and just like yourself they were commercially purchased.  Even the verts from the holotype of Sigilmassasaurus were acquired from an English dealer.  So although I was pulling your leg on the composite skull who knows what you will see offered for sale.  Dealers don't even get the common items ID correctly so the opportunity to see more mislabeled skull bones is good.  I remember standing behind a notable paleontologist at one of the better Moroccan tents at the Tucson show they're opening up a crate from Morocco full of bones, bones and more bones.  He had first dibs and pulled out a Spino spine and a few very cool looking other items.  Just a very different collecting environment than most other localities.  Without the commercial digger we would know much less than we do today. 

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Yes having first dibs can be pretty great. I'm a bit torn on seeing misidentified bones on the internet. Seeing a rare misidentified bone can be a wonderful opportunity to get something special no one else noticed. But at the same time as someone who loves to share knowledge and science it's a shame so much material changes hands without much information on the bones and a lot of info can be lost as well, which is why I try to share as much info as I can when I find out something about these wonderful faunas.

Olof Moleman AKA Lord Trilobite

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What you are say is very true with most Kem Kem material that is sold online or locally.  The good news is that it does become available and does get into the hands of paleontologist.  Yes its not perfect but better than being locked up in the Kem Kem and not available to science.

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