Printing Lots of Bones

I've been getting ready for a big display about Bernie at the "Regional Show" here at the Washington county fairgrounds this weekend. This show consists of displays from 5 local clubs - lapidary, rock and fossils. We have this show every year at the Washington county fairgrounds in October. The NARG fossil club is one of the larger clubs exhibiting.

This year one of the advertised headlines for the show is Bernie "Older than Dinosaurs!". So I've been working to put together a good presentations. I'll have two display cases as well as bringing my 3D printer (and running it). I may also bring my 3D scanner as well, though we may be tight for desk space for it.

So for a good display I've been printing bones - Lots 'O Bones - though I haven't printed out all the bones we have prepared. For the bones that are centerline (brain cases, vertebra) I only have one of each. For the rest I've been printing out mirror images as well as the originals so as to recreate a full animal. Here is what I have to-date:

We have a full skull in white: the original half-skull below it. Skull roof pieces from two other skulls with their mirror images. Two premaxillas, one with a mirror image. Three braincases, and parts of a 4th and 5th. Some internal skull bones - probably related to the palate. Two humeri - we have other limb bones but I haven't printed them yet. A start of the tail - thirteen bones out of a total of 65 (see why I picked 65 later). These vertebra are 1,5,10 etc - the graduations between the adjacent vertebra are finer. And a 1/2 and 1/4 scale mason's hammer!

As you see, these bones are quite glossy. They are all printed in ABS and have been smoothed with hot acetone vapor. It is harder to print large pieces with ABS but the smoothing process makes it worthwhile. 

So here is the process I have followed to print out the graduated series of tailbones for a full size reproduction. 

1) Have a good bone to copy. In real life, a body vert is not like a neck vert is not like a tail vert. However, I have a really good centrum + neural process combination that I wanted to copy so I used that. Here's the picture taken during scanning: 

It is the best combo found to-date. 

2) Have a good know specimen to copy and get dimensions from. Since we don't have an articulated  specimen of Bernie, I have chosen to get dimensions from a wonderful specimen of Midentosaurus Brevis from China. This animal is about the same size as Bernie, the same age, and is wonderfully complete. Here is the reference article data: 

 Look at how complete this specimen is! This thing is 12 feet long!

Best of all, they have closeups of the tail so I can get accurate dimensions of all the tail verts! And they all have neural processes (probably to make a flattened tail to swim with) so my choice of a vert+centrum can be partially justified. Wait until I get the chevrons (the little Y-shaped bones under the verts) printed too. This animal had 13 neck verts, 25 body verts, 2 sacral verts and 65 tail verts (that's where the 65 comes from).

3) I took measurements of the length and diameter of the verts (minus the neural processes) and put them in a spreadsheet. I did a curve-fit on the data, and projected out the dimensions of each vert as a percent of the largest (number 1). My inner engineer is showing. 

4) A series of bones is then prepared in the Slic3r software. I can import the scanned bone:

Set it upright and duplicate it. My computer can only handle 6 copies at once, so I'll end up printing variations of this about 11 times. 

Now, each individual vert can be scaled according to the dimensions on the spreadsheet to gradually decrease in length and width as we go back the tail. The two dimensions do not scale at the same rate - the verts get smaller in diameter faster than they get shorter, so the verts become skinnier and skinnier. 

5) Last of all, the bones are printed, cleaned up and vapor-smoothed. I've printed up 13 but some will have to be done again as the initial scaling was incorrect. Overall they will be a tail about 50 inches long! 

This goes to show some of the real benefits of 3D scanning and printing instead of moulding and casting. Scaling objects and making mirror images is really easy using 3D digital techniques. 

Sincerely, Greg Carr

Mandible or Maxilla - it's complicated!

I posted a few pictures of a skull fragment and a piece of bone that I thought was a mandible. The mandible, of course, is the lower jaw. These both came out of block 1. Here is the skull piece:

Here is the other side, the probable inside

And here is what I thought was a mandible piece:

We also have a little more of this second bone that was in another block (block 2). It was prepared last year and the two pieces have now be re-united. Block 1 and block 2 broke naturally, and the bone spanned the gap across the two blocks. The smaller piece is closer to the body, so it is the proximal part. Fitting these two bones together we can clearly see the teeth at the  distal end of the jaw bone, while it apparently transitions to a groove without teeth on the proximal end:

After re-assembly is is clear that it is not clear how this bone - the supposed mandible - fits into the curved jaw. Thalattosaurs have weird jaws and tooth structures, but this is just plain not working. Here's a whole bunch of pictures from the web illustrating their strange mouths:

Vancleavea

Xinpusaurus

Askeptosaurus

Bamaolinensis

Mesosaurus and relatives

Endennasaurus

I told you their jaws were strange!

Worst of all, the best way it fits is as part of the upper jaw. This would make it another Pre-Maxilla, or the Maxilla. But is looks nothing like the two other pieces of upper jaw we have - one on the whole skull, one excavated last month! These pictures are taken of the accurate 3D printed copies as the originals have now been sent to Alaska for study.

However, I think this picture clears up some confusion. 

It is the inside of the front of the skull and the similar part of the unknown bone. They look very similar, except the new bone is smaller. There is a clear depressed notch on the right end (proximal) of the bones. I measured the distance from the left end of the bones to the beginning of this notch. The whole skull is 95 mm - the new bone is 85 mm. So we either have a younger animal, or the other sex. This might also explain the differences in profiles of the nose - sexual dimorphism? Age Progression? Natural Variation? 

With a Puzzled Perspective, Greg Carr

PS I sure like working with 3D printed reference materials - they don't break when I drop them!

Mandibles and scraps

I'm collecting pictures of all the mandible parts that we have found to date. A long time ago we found our first piece of mandible. This gave us the first clue that skull pieces would be found, even before the actual half-skull was found. Then we found an enigmatic piece which looks like an Ichthyosaur mandible piece, with a groove for tooth roots. I'm not sure now that is came from an Ichthyosaur since we have not found any other pieces like it. Here are pictures of both of them.

Here is the second definite mandible piece. It is split and the tooth roots are visible in the jawbone.

Latest, we have a more complete mandible in two pieces. One was excavated last year, the other piece a few weeks ago. They are both from the same bone, but were located in two blocks (block 1 and block 2) and were broken through when the blocks broke. This is the most complete fragment so far. It clearly shows that the front part of the jaw had teeth in sockets, but further toward the rear it transitioned to a grooved bone that may not have had teeth. Think of a horse, with cutting teeth in the front and molars in the rear separated by a vacant space. ( where the bit goes).  Other known thallatosaurs have weird tooth patterns so this is not surprising, I'd really like to find a whole lower jaw, or at least more toward the rear, but you get what you get on these beasts.

I wish you could see the detail in these teeth. They even have small pits in them. A retired dentist friend of mine ( Greg Gentry) from the NARG group says it's probably a case of the enamel wearing through and exposing the dentin, Since the dentin is softer, it wears away and forms a pit or depression. Anyway it's really cool and wonderful to think that these teeth were used 230 million years ago and were made the same way as current teeth, even though tey are reptile and our teeth are mammal.

 Last of all, I've been going through the back-log of bones removed from the block but not yet finished. This includes a lot of smaller fragments and backbones  - centrums. They don't tell us a lot scientifically so they have a lower priority, but we need to do them eventually. Here are a lot of rib fragments:

Ans here are a couple of centrums - the force-bearing part of the backbones. One of these is very unusual by being thin for it's diameter. We have one or two like this already. They both show the typical hourglass figure where the neural arch attached to them, so we know they are both from these thalattosaurs. 

Sincerely, Greg Carr

Back in the Saddle (Prep Chair) again

Well here we are back from our trip to Alaska. During that trip we visited :
1) The Royal Tyrrell Museum in Drumheller, Alberta- it is Mecca for dinosaur and Ichthyosaur lovers.
2) The Peace River Paleontology Research Center  in Tumbler Ridge, British Columbia - shoestring budget but great potential, especially if you love animal tracks. Visit them in the late summer for best viewing of track sites.
3) The University of Alaska Fairbanks - imagine a giant painting of Hydrosaurs under the Northern Lights!
4) A dig with the U of AF on the first Elasmosaur found in Alaska - we recovered 14 backbones, a couple of ribs and a scapula. Not bad for two days standing in ledges about one foot wide that were about 50 feet up a 100 foot cliff!
5) The Discovery Place in Prince George - nice replicas of dinosaurs including one big sauropod that stretches through three rooms.

A few notes about timing. We left in mid-May and returned in mid-July.
1) We got out of Alaska before the mosquitoes got too bad.
2) We got out of Alaska before the fires got too bad and obscured the views.
3) If you go to the Canadian Rocky Mountains before June 1st plan on camping in Banff, as other campgrounds are still closed.

Back at OMSI, I have now finished preparing a very interesting piece of skull. It appears to be from the 'nose' region of a second skull, between the Nasal passage and the end of the snout. However, it does not exactly match what would be the same section in the first big skull we have prepared. Perhaps it is from a much larger skull, and was broken off somewhere above the inner (top)(proximal) end of the teeth. Anyway here are some pictures. The 3D printed version of the first skull is in the background for reference.

Getting ready for the big trip

My wife and I  (Peggy and Greg) have been planning a big road trip to Alaska for a number of years. This year we are finally doing it. We leave on May 18th. We plan on spending 2 months or so, driving all the way to Prudhoe bay and seeing the midnight sun. Preparations to do this have occupied a lot of my time over the last few weeks. I'm not turning this blog into a road trip journal, but I may include some Paleo-related stops such as the Royal Tyrrell museum, the peace river paleo center, ammonites in Alaska and other juicy bits.

At OMSI, we've been slowly grinding out bones and doing a lot of scanning. The student I've been working with at Century High school has gotten really good. She can scan a bone, fix all the problems and have it ready to upload to our files in about two hours. Sadly, school is almost over and I'll have to find another way to get the bones scanned later in the summer. Portland Community College has a scanner, perhaps I can do it there. Here is the latest batch of scanned bones sent off to Alaska. We have a textbook centrum and neural arch [242], two possible radii [245,246], the smallest humerus [262], the fifth braincase [265], a coracoid [263], part of a skull internal bone [247], and one bone I have no clue [257].

For new bones, I only have one strange bone that may be part of a juglar, though I'm not sure. And sadly this is all we will have of this bone. It was sheared off at the surface of the concretion - the rest is lost somewhere in space and time. The smaller bone next to it is a miniature radius, or at least it is a smaller version of the pair of bones sent to Alaska shown above. I have a still smaller one yet - hurrah for an age progression!

Nestled against this bone was the first loose tooth we have found. I think it's a palate tooth, as it is very small. The bit of bone visible in the photo is about 2/3 root+bone, and only 1/3 was the exposed bone. The crown is only about 2 mm wide and 2mm high. I tried to get a picture through the microscope eyepiece. It is perfect - even the grooved surface of the  tooth is present. 

Last of all, we had some fun in the lab this last week. The traveling exhibit being installed this week is "Ripley's Believe it or Not"(R). One of the exhibits got broken in shipment. It is the actual skull of a two-headed calf! Since we deal with broken bones a lot in the Paleo lab, the exhibit guys asked us to repair it. I undertook the job. The bone structure, as you can expect, is bizarre, There are two noses, three orbits, the jaw is a "W" shape, and being a newborn the bones are extremely fragile. But with the help of modern glues it's back together, and on exhibit!

Sincerely, Greg Carr