Jump to content

Penn Dixie Trip


gcaruso

Recommended Posts

If that diagram is accurate, then it is contradicting the belief that pretty much every trilobite you find is just a shed. Granted, at Penn Dixie, lots of partials are found, but the huge number of complete ones is pretty amazing. So, am I correct to believe then, that any complete eldregeops was a live animal when buried?

Link to comment
Share on other sites

...If that diagram is accurate, then it is contradicting the belief that pretty much every trilobite you find is just a shed...

The notion that most trilobite fossils are molted remains is wholly inaccurate. Whether they are molts or not is simply luck of the draw, some formations yield mostly complete trilobites while others don't. Check all the popular books, there are numerous examples of complete trilobites that were fossilized as complete animals.

image.png.a84de26dad44fb03836a743755df237c.png

Link to comment
Share on other sites

The notion that most trilobite fossils are molted remains is wholly inaccurate.

Is it safe to say that whole body fossils were live (or freshly dead) at the depositional event and that partials are likely molts, with the chance that a dead trilobite somehow ended up in pieces when buried?

Link to comment
Share on other sites

Of course there is also a theory by Rustan et. al. that they proposed in 2011 and was put into video form (process starts about 30 sec. into video):

https://www.youtube.com/watch?v=we0-KTi4KsE


Infaunal molting in Trilobita and escalatory responses against predation, Juan J. Rustán, Diego Balseiro, Beatriz Waisfeld, Rodolfo D. Foglia and N. Emilio Vaccari
Geology, v. 39 no. 5 p. 495-498

But I like the theory by Speyer better. :)

Edited by Shamalama

-Dave

__________________________________________________

Geologists on the whole are inconsistent drivers. When a roadcut presents itself, they tend to lurch and weave. To them, the roadcut is a portal, a fragment of a regional story, a proscenium arch that leads their imaginations into the earth and through the surrounding terrain. - John McPhee

If I'm going to drive safely, I can't do geology. - John McPhee

Check out my Blog for more fossils I've found: http://viewsofthemahantango.blogspot.com/

Link to comment
Share on other sites

On 9/8/2014 at 4:58 AM, Shamalama said:

Of course there is also a theory by Rustan et. al. that they proposed in 2011 and was put into video form (process starts about 30 sec. into video):

https://www.youtube.com/watch?v=we0-KTi4KsE

Infaunal molting in Trilobita and escalatory responses against predation, Juan J. Rustán, Diego Balseiro, Beatriz Waisfeld, Rodolfo D. Foglia and N. Emilio Vaccari

Geology, v. 39 no. 5 p. 495-498

But I like the theory by Speyer better. :)

 

 

The good news is you don't have to choose, infaunal molting was not suggested as a counter argument to Speyer. Instead it's just as the title suggests; a different exuviation strategy than the traditional Salterian method used by phacopids. The attached figures demonstrate how the molted cephalon interacted with the sediment during this process. It's really a remarkably clever strategy considering the obvious vulnerability of a freshly molted 'soft-shelled' trilobite.

 

IMG1.jpg

 

 

 

  • I found this Informative 2

image.png.a84de26dad44fb03836a743755df237c.png

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...