Sunday, March 10, 2019

Finishing up with Teeth, waiting for the Classification paper

I haven't posted much in the last 8 months as I haven't had much to post about. Most of the rocks have been taken apart and the bones extracted. The hard work of writing the classification paper is being done by Eric Metz at the University of Alaska, Fairbanks. He recently successfully defended his Masters Thesis which is the basis of the classification. I haven't seen it yet, and am anxiously waiting for it to be submitted for publication in the Journal of the Society for Vertebrate Paleontology (SVP). The companion paper, describing and classifying a smaller articulated (beautiful too) thalattosaur from Kake island, Alaska is also in the works.

I have been slowly working on the last of the "Bernie Blocks" at OMSI. There have been two toothy surprises recently. One is apparently the tooth of a Phytosaur. These animals closely resembled modern crocodiles through convergent evolution. They are common in New Mexico but this is the first evidence of them from Oregon.


Here is a reconstruction of what a Phytosaur may have looked like (courtesy of Dr Jeff Martin, NPS, Petrified Forest NM)


Here is what our tooth looked like (in life it's about 3cm long):
 

It is very nicely preserved with the original concavity at the root intact. I think it's a shed tooth. Maybe some of the other unknown bones we found may be Phytosaur scutes as well, though poorly preserved. 

In addition to the Phytosaur tooth, there is another jaw fragment with teeth. This one, funny enough, was set aside as it was broken lengthwise along a thin section so it looked exactly like a split rib. Since we've got lots of ribs, I didn't put a priority on working on it. But Surprise! it turned out to be a very important jaw fragment - Dr. Pat Druckenmiller at the UAF thinks it is a Dentary, the front end of the lower jaw! Since we didn't have that before, it's really great - and it's almost the last thing I'll ever prepare! Life sure likes a big joke once in a while. 

So now we're just waiting for the classification paper to come out. Then I will post clean scans of all the 180 scanned bones on Morphosource, and maybe Eric will post the digitally reconstructed skull as well.

I don't know what other studies will be done on this specimen in the future, but it's sure been a great time! G Carr

Sunday, June 10, 2018

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

Tuesday, January 16, 2018

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.





Friday, January 5, 2018

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

Thursday, November 9, 2017

tiny bones in the rocks

When I was much younger I was lucky enough to see Don Ho in Honolulu in his Waikiki stage show. His favorite song was 'tiny bubbles'
(Tiny bubbles (tiny bubbles)
In the wine (in the wine)
Make me happy (make me happy)
Make me feel fine (make me feel fine)...

When I see tiny things I often think of this song. Anyway, not all the bones I find in these 'Bernie Blocks' are large - some are very tiny. I have recently prepared 3 small bones, which may or may not belong to thalattosaurs. I've blown them up quiet large, as they are each less than one inch long. The top center one may be a worn neural arch, and the left one is definitely a limb bone or digit. The one on the right is a complete mystery - I suspect it may be an amphibian bone of some type. It is very thin, most of it is less than 1 mm thick, so it was 'difficult' to prepare, to say the least. However it's nice that it's finished. Maybe the guys in Alaska can figure out what they are. 
Sincerely, Greg Carr




Thursday, October 19, 2017

Bones, Bones - Lots of Bones

I'm doing a project that is giving me perspective on how much we have accomplished in the past 5 years. I have decided to print out a reference set of all the bones I have prepared so far. In fact, I have decided to print out 3 sets - one for myself, one for OMSI, and one for the University of Oregon's Condon collection. Right now I have scanned about 138 bones, so 3 sets will have 414 bones. In addition, most of these bones are not from the centerline of the animals. So if I print both the original bones and the mirror images, I will have about 700 bones.

I have been printing the bones for about a month out of ivory-colored PLA. It prints well, and I'm enjoying it. So far I have printed 33 sets of 3 bones, about 3 per day. At this rate it will take another 15 weeks or so for the original bones to be printed, so I won't get them all done by Christmas.

Here are the skull bones I have printed so far. This is only about half of the total number of skull or brain-case bones that we have. This really makes me thankful to have so much skull material! This is truly is a treasure.

Here are the other bones I have printed so far. Keep in mind that this is only about 1/4 of what I will eventually end up with. So many Bones!


And here is the workhorse - my printer. 


But wait - there's more! I have  lot of bones that I have not scanned. Most of them are fragmentary or are part of groups that I don't intend to totally prepare. This is because most of the groups contain bones we know well, or are very aesthetic. There are another 160 or so bones or parts of bones in the cabinet at OMSI These too will go to the University of Oregon, along with the bones sent to Alaska. 

But wait - there's still more! These bones have been taken from only about 2/3 of the find - we still have 1/3 to go! 

So ultimately I predict we will have (138+160)*3/2 = 450 unique bones !

Ribs and Gastralia


Other stuff

Backbones - centrums & neural arches


 Sincerely, Greg Carr

Wednesday, September 27, 2017

Just more backbones - as if we don't have enough of them!

Just a quick note to tell all you folks about more backbones that I've prepared. Sometimes the backbones cluster together - must be something about how the water currents & waves sorted items of similar density and shape together. Anyway, I have been working an a small rock about the size of two fists together. This rock has at least 6 backbones, maybe more. We have both centrums and centrums combined with neural arches. Some are rather unusual in the way the rib attachment knobs on the centrums look. I believe that the rib attachment point (on the centrums) migrates from the top  to the bottom of the centrum side as you go from the front of the rib cage to the back. So if you know enough you can tell where the backbone came from. However, I'll leave that to the guys in Alaska to figure out.

Here's two centrums hooked together. I was able to separate these with a bit of care. The big one on the bottom had a short, robust neural arch that was not blade-shaped in cross-section. Instead it is an oval cross-section, pretty robust.

 Here's a view of the prepared centrums I just sent to Alaska. The top group has 3  centrums as well as a nautilus, perched directly on the end of a centrum. Pretty cool! 


 Here's a centrun+neural arch that has the centrum rib attachment knobs on the side blending into the neural arch on the top. Must have come from the forward part of the rib cage. 
  And here is a rib with the neural arch that has no rib attachment knobs. Perhaps this came from the neck, where there are no ribs?
I still have 2 more backbones to finish preparing from this rock, and maybe more hidden inside it. Anyway, that's all there is for now. 
Sincerely, Greg Carr