It is amazing that the shell on these seems to have no distortion. You would think that to be compressed into a single plane like that they would show some kind of breakage.
Thanks Jean. I like this paper too Terri and Solius. I've still not seen Mehl's paper on the Silurian Michelinoceras with arms.
I wonder if perhaps early dissolution of the shell could be an explanation for the lack of obvious crushing and breaking Kevin
Here attached is a closeup of part of the group of orange objects in the smooth-shelled orthocone (95 mm long), field of view about 2.5 mm so they're tiny. The arrowhead-shaped one looks a bit like a rhachidean tooth and there are several more elongate structures reaching about half a mm long in that area. I'm not sure. It would be great to find an articulated radula in these rocks.
Great thought Kevin. I just found my old UV lamp again and the only thing that lights up (apart from a few scattered dust particles) are the robust-looking phosphatic structures in both of these orthocones. Tempting to think of these as beaks, but in the strongly ribbed individual there's a carbonized structure in front of that which is similar to what I think has been interpreted as mandibles in the coiled nautiloids of Bear Gulch. CT and Xradiography could show something, but contrast in these specimens will be less than in the cases of pyritized fossils in mud rocks.
We are a participant in the Amazon Services LLC Associates Program, an affiliate program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.