New kid on the block - a Sabertooth Salmon!

I haven't posed much about the thalattosaurs lately, as there hasn't been much new to report. The rocks I'm working on at OMSI are pretty barren. A typical rock the size of my head contains one or two bones, almost always ribs, gastralia or centrums. I have found another partial braincase, bringing the total to 7! However, it's been pretty boring. I think I'll be done with all the blocks around the end of the year.

However, fossil preparation continues. One new addition is one of my favorites - a "Saber Tooth Salmon"! These large salmonoids lived about a million years ago, and swam up rivers in the western US (none have been found in Canada or Alaska to-date). They were 8-10 feet long (2-3 meters) and weighed 400 pounds (180Kg). he best remains have come from a gravel quarry near Madras Oregon, the ancestral river bed of the Deschutes river.

A very complete fossil skull and articulated backbones came up on an Ebay auction earlier this year. I was lucky enough to purchase it for the University of Oregon, which has the holotype and two other specimens. This specimen was collected in 1980 by Reuben Holleman, a local fossil collector. He prepared it and kept is safe for almost 38 years before selling it as part of his collection liquidation. I did some more preparation of the skull, removing the majority of the remaining matrix and making archival cradles for both skull parts. This really is the best specimen of this animal in the world - I'll let the pictures speak for themselves!. It is on display at OMSI for the next few years as the U of Oregon has no place to display it. The UO and I are working on dating the site, and OMSI and the OHSU (Oregon Health Science University) will be working on CT scanning/printing to make copies.

Here is the skull in all its glory, about 20 inches (50cm) long - that's a 6 inch (15cm) ruler beside it!

Articulated backbones and a fin

Ribs

Still more ribs

And another set of ribs (well, what do you expect from a 2 meter animal?)

Bones as displayed in a case at OMSI

The two large teeth stick sideways out of the upper jaw - perfect for fighting other fish!

Front ends of the jaws, the original on the left and 3D print on the right

Epic printing Jobs - Part 2

One block of fossil bones and shells I plan on leaving as a display piece, as it looks really cool and yet has no unique bones in it. I scanned it recently and intended to print it out. It is a big print - it takes slightly more than 1 full roll of filament, and takes about 5 full days to print! Things went fine for the first 4 days - about 102 hours or printing - then disaster (of sorts) We had a power blip, which reset the printer and the print stopped!

So I figured out roughly where the print stopped and made a small print of the remaining piece. Since I couldn't get it exact, I printed a little more at the interface and will have to physically trim the piece to fit. You may also notice that the print changes from Ivory to White. I thought I had another roll of Ivory when I started - opened the box and it was white! So I had to splice in white on the fly (always fun, but I've figured out how to do it.)

 I don't plan on doing another one.

 The printer has also developed a rather nasty Z-axis wobble. The Z-feed screw spontaneously developed a 0.010 inch (ten-thousandths) bend, and the linear guide bearings are poor enough that they don't keep it straight. I've re-bent the screw to be straight and ordered some new bearings. We'll see if that fixes it.

Sincerely, Greg Carr

 4 days and counting - almost done!

 The (almost) finished product.

Epic 3D Printing jobs - part 1

I haven't had too much new in preparing actual bones lately - ribs, gastralia pieces, centrums and neural arches. All well known stuff, even somewhat boring. No limb, skull or unusual bones at all. Several large blocks have been pretty barren of bones, so they quickly went from 'unprepared' to 'scrap' piles.

What I have been busy with is 3D printing. I decided to print out 3 reference sets of bones - basically all the scanned bones that I have files on. I had never seen all the bones all together, since as soon as they are prepared and scanned I send them off to Alaska for Eric Metz to study. So I decided to make 3 sets - one for OMSI, one for myself, and one for the U of Oregon. Since I have about 150 scanned bones, this makes for a LOT of 3D printing - about 450 individual pieces!

Well, I'm done with that. It took over 3 months with the printer running 12+ hours a day. To get the best quality surface print quality, I found that making the prints very slowly gives the best surface. The specifics of the printing are roughly as follows:

Ivory PLA material. 1.75mm filament
0.3 or 0.4mm nozzel
205 C extruder temperature
80 C heated bed temperature
10 mm per second outer perimeter speed (very slow!)
3mm thick shell
25% fill
So here are the bones laid out on my family room floor. For scale, the planks are 2.25 inches (60mm) wide. Quite an impressive lot. The skull, of course, is both the original and it's mirror image to make a whole.

 So looking at these individually I have 7 ribs. Actually I have prepared a LOT more, but since most of them are short broken pieces I haven't scanned them. Some ribs are thin with a figure 8 cross-section, some are round and tapered.

 Nest to them I have limb bones. Some are quite small. One is stuck in a chambered nautilus. There are about 33.

 Next we have shoulder and pelvic bones. I have about 13.

 These are unknowns. I swear some of them are osteoderms, except that thalattosaurs don't have them! Perhaps the guys in Alaska have identified them by now.

 Next through the center of this picture are the skull & braincase bones. Along with the large half-skull, there are most of the other skull bones like the pteregoid, volmer, postorbital, etc. We may have part of the mandible, but no complete mandible! In total, about 32 bones including 6 brain cases (two not pictured, they are in Alaska before I got them scanned).

 Last of all, backbones. About 50 whole & partials are not pictured as I sent them to Alaska without scanning (who needs 80 backbone scans?). There are 6 centrum+neural arches paired together, 29 separate centrums, 17 separate neural arches , and 3 chevrons. One chevron is so big it may have come from a 30 foot (9m) animal!

Sincerely, Greg Carr