Newly Prepped Protosphyreana Fin

[Xiphactinus]

Since it's SOOOO cold here in the Midwest and I can't get out, I finally got around to prepping one of the pile of jackets I have in my basement that we've collected in the Niobrara Chalk of Kansas over the years.

This is a small Protosphyreana pectoral fin. It's just over a foot long. (We have others that are over 3 feet long.) Protosphyreana is a swordfish-type critter that is mostly known from its serrated pectoral fins and its rostrum.

This specimen was collected in 2002. The tip is missing as that was what was weathering out.

A bonus was the scapulo-coracoid (shoulder girdle) was associated with the fin as well as a skull fragment.

I neglected to take photos at the beginning of the process, so what I didn't document was the removal of the rock covering the fossil and the cutting down of the jacket.

What is documented is the cut down jacket with plaster poured around it to make a rectangular display. The tip is reconstructed with plaster and painted to match the bone. Finally, the plaster is "painted" with dissolved chalk that makes it look like it's a piece of chalk rather than plaster.

http://oceansofkansas.com/Protosphyr.html

Edited February 10, 2014 by Xiphactinus

[vertman]

Very nice fossil! Well-prepped too!

[Malcolmt]

Thanks for the explanation.... neat stuff always like to see what goes into different types of prep work.

[KansasFossilHunter]

Looks great! I'll have to try squaring method that with some of my fins.

[KansasFossilHunter]

What did you use to "paint" the tip of the fin after it was reconstructed?

[Xiphactinus]

I use acrylic paints...mix black, dark brown and a little yellow until it matches the bone. After the paint dries, I paint the entire thing with VERY dilute slurry of chalk and water. That gets chalk down into the nooks and crannies. Then I coat the entire thing with dilute vinac.

[Ramo]

Looks great! Just wondering if there is a label or photo, or something going in the space under the fin.

Ramo

(I remember finding a small section of the leading edge of one of those and thinking it was some kind of jaw with teeth.)

[Xiphactinus]

Ramo - I wasn't thinking that, but great idea! I'll add a reconstruction of the fish there.

[ZiggieCie]

It is so great to learn every ones little tricks to a great job, so we don't have to re-invent the wheel every time.

[sward]

Nice find and prep. Obviously with this winter wx, it's a good time to do prep work. I'm going to have to set-up a prep room in my basement. I'm leary of running my compressor in the garage when it's this cold.

Thanks for sharing this with us.