Ventral (?) prep - Marjum trilobite

[jort68]

First of all, apologies for the image quality. I know flash can be pretty horrid but it's all I can do at the moment. Side-views will be found in the following posts!

 

 

 

I collected this (probably molted) trilo at Marjum pass in Utah a few weeks ago. The depth of the axial lobe and how the pleurae seem to flare up led me to believe that this specimen is on its back. 

I only have a pin vise at my disposal and I don't want to ruin a good specimen with the incorrect equipment, but I wondered if anyone has heard of pin-vising Marjum shale. Would you use air abrasion? In that case I will save it for a few years when I can afford it (:

 

Thanks for reading, hope everyone's staying safe!

[jort68]

 

[Kane]

It depends on how hard that matrix is. If it is relatively soft enough for a pin vise, then maybe it's a go (a very slow one, no doubt!). If it were mine, I would be using air abrasion, or even possibly flip it on another piece of matrix to prepare it dorsally. You're probably right that it is a moult on account of not seeing the librigenae.

[jort68]

This whole thing has got me seriously considering investing in a scribe.. If I were to use air abrasion, would it be detrimental in your opinion to try uncovering the ventral surface as is? You suggested prepping it dorsally but I would really like to unveil its underbelly if it wouldnt damage the specimen!

[Kane]

As long as you're careful, a ventral prep is more than possible. Unless I was using a very fine scribe, I'd be nervous scribing it and instead go with abrasion. Going dorsal in this case would not be an entry-level prep, and if you haven't done a flip before, you are definitely better off going with the initial plan of a ventral prep. I would be very careful at the pleurae tips.

 

It is challenging to prep out what amounts to pockets as opposed to something more convex. If you can track down some images of this species on its ventral side, and keep it handy while you prep, that will act as a helpful guide to avoid any wrong assumptions where everything is!