Stegosaurus Ischium

[The Speeding Carno]

Hello,

 

I've been on the look for stegosaur fossils for a while. I found this on an auction site. I've no real information on it other than it was found in the Morrison and is supposedly a stegosaurus ischium. 

[Chase B.]

Dear the Speeding Carno, 

 

The specimen above does seem to be bone, especially from the left end of the photo. If it were the ischium of a Stegosaurus spp., it would firstly be oriented the opposite way. Notice how the specimen thins towards the left end of the photo. That end would be facing the caudal end of the animal. Unfortunately, no autopomorphies for Stegosaurus occur on the ischium (e.g., Galton and Upchurch, 2004). The specimen is nevertheless the correct shape to be from a stegosaurid, and the still-attached matrix does seem to have affinities in color to the Brushy Basin Member of the Morrison Formation, a notably fossiliferous layer known for its dinosaur specimens. Thus, I believe the best identification possible based on your photograph is that of an ischium of Stegosauridae indet. I am still a little shaky on identifying it as a stegosaur, however. Could you provide an additional photograph of the specimen the other side up with a scale bar and of higher quality/detail if possible? If you could, I'd feel much better about any identification I could make. Additionally, as I am a museum researcher, I feel obligated to note (though you probably already know this) that unless the seller collected this specimen from private property where he/she had permission to, it is illegal to collect (as well as sell) vertebrate fossils found on federal land in the United States. 

 

Best Regards,

 

Chase

 

References. 

 

Galton PM and Upchurch P. 2004. Stegosauria.  In Weishampel DB, Dodson P & Osmólska H, eds: 2004. The Dinosauria, 2nd Edition. Berkeley: University of California Press. pp. 343-362. 

 

Here is an image of the Stegosaurus ungulatus at Yale just for fun as well:

 

 

 

[The Speeding Carno]

1 hour ago, Chase B. said:

Dear the Speeding Carno, 

 

The specimen above does seem to be bone, especially from the left end of the photo. If it were the ischium of a Stegosaurus spp., it would firstly be oriented the opposite way. Notice how the specimen thins towards the left end of the photo. That end would be facing the caudal end of the animal. Unfortunately, no autopomorphies for Stegosaurus occur on the ischium (e.g., Galton and Upchurch, 2004). The specimen is nevertheless the correct shape to be from a stegosaurid, and the still-attached matrix does seem to have affinities in color to the Brushy Basin Member of the Morrison Formation, a notably fossiliferous layer known for its dinosaur specimens. Thus, I believe the best identification possible based on your photograph is that of an ischium of Stegosauridae indet. I am still a little shaky on identifying it as a stegosaur, however. Could you provide an additional photograph of the specimen the other side up with a scale bar and of higher quality/detail if possible? If you could, I'd feel much better about any identification I could make. Additionally, as I am a museum researcher, I feel obligated to note (though you probably already know this) that unless the seller collected this specimen from private property where he/she had permission to, it is illegal to collect (as well as sell) vertebrate fossils found on federal land in the United States. 

 

Best Regards,

 

Chase

 

References. 

 

Galton PM and Upchurch P. 2004. Stegosauria.  In Weishampel DB, Dodson P & Osmólska H, eds: 2004. The Dinosauria, 2nd Edition. Berkeley: University of California Press. pp. 343-362. 

 

Here is an image of the Stegosaurus ungulatus at Yale just for fun as well:

 

 

 

I'm very sorry but there is no additional pictures at the moment. I am, however, asking the seller for more pictures. The seller bought the fossil from another dealer, and received no other information. I'll be sure to ask though.

I'll let you know if they reply!

[hxmendoza]

Here are photos of a cast of the isolated left ilium of a juvenile Stegosaurus stenops that you can use as a reference. Cast made by Ken Carpenter after he restored it while at DMNS. He gave me a copy. The original specimen is from Big Horn County, Wyoming. 

 

Also a computer 3-D rendering of the right ilium of Sophie at the Natural History Museum, London.

 

Both the ilium and The entire Sophie skeleton were discovered by my good friend Bob Simon at the Red Canyon Ranch Simon Quarry. I played a small role in the discovery of Sophie in correctly identifying the articulated caudal vertebra for him when he had it out in Virginia. I suggested where the spikes would probably still be in the ground. When he went back, he found the entire skeleton and the spike where I suggested they would be.

 

Hope they are helpful.

[The Speeding Carno]

7 hours ago, hxmendoza said:

Here are photos of a cast of the isolated left ilium of a juvenile Stegosaurus stenops that you can use as a reference. Cast made by Ken Carpenter after he restored it while at DMNS. He gave me a copy. The original specimen is from Big Horn County, Wyoming. 

 

Also a computer 3-D rendering of the right ilium of Sophie at the Natural History Museum, London.

 

Both the ilium and The entire Sophie skeleton were discovered by my good friend Bob Simon at the Red Canyon Ranch Simon Quarry. I played a small role in the discovery of Sophie in correctly identifying the articulated caudal vertebra for him when he had it out in Virginia. I suggested where the spikes would probably still be in the ground. When he went back, he found the entire skeleton and the spike where I suggested they would be.

 

Hope they are helpful.

A small role? I'd say that's a fairly large role! Anyways, thanks for the pictures!