Fatal Embrace

[Denis Arcand]

Here's a cracking fossil: a receptaculites? molding a gastropod shell. Collected by me from the Ordovician period in Quebec, Lorraine Group part of the Nicolet River Formation.

Although this photo is not visually spectacular, it is still of great paleontological interest. If the receptaculites is oval instead of being circular, it might be because the gastropod had started to eat the rim in a spiral motion, and then a fatal event sealed they destiny?. The duo were suddenly buried to the delight of us paleontologists who can now study the interaction of two distinct species. We can see clearly the trace of the gastropod shell in the softer receptaculites, the shell which left the imprint has since come off. 

 

I believe the two species to be respectively R. Occidentalis and Murchisoniidae or may be an Hormotoma gracillis like the one in @Jeffrey Pcollection . I'm probably wrong, it could also be a colony of bryozarians instead of receptaculitids, I'm not sure. Because of the bad condition of the fossil, I'm unable to see the sunflower pattern.

 

What do you think?

 

 

 

[Rockwood]

2 hours ago, Denis Arcand said:

We can see clearly the trace of the gastropod shell in the softer receptaculites,

That gastropod had made it's last trace some time before it's shell was enveloped.

[Ludwigia]

I could imagine that the gastropods were either already deceased remnants or died while grazing before their shells landed flat on the objects which then partially encapsulated them.

[Rockwood]

Ya. They're slow, but not that slow. I think a gastropod would still beat a sponge in a 'foot' race.