A brief sidebar - Time Lapse Photography

I've always wanted a time-lapse camera! When I was a kid my dad (Eric Carr) built a time lapse camera attachment to go on the family movie 8 camera. If you pushed the switch one way the camera took movies. If you pushed it the other way, it took one frame. My father built an apparatus that worked on a clock motor that would push the 'one frame' button once a minute or so. I remember the wonder of a home-made time lapse movie.

Last month I picked up a rather nice Fuji digital camera, but it doesn't have a time-lapse function. I have researched and found some Canon cameras can have a software 'hack' to allow internal programmed time lapse, but my Fuji camera doesn't support that.

So I went back to my father's idea. I built a frame to hold the camera and bought a small gear-motor that runs on DC power. I decided that I wanted the setup to run on 12 volts DC so that I could run it off a car battery when out camping or fossil hunting. A variable voltage power supply is easy to make from a Texas Instrument LM338 variable voltage power chip and a couple of components. This will allow the gear-motor to be supplied with a variable DC voltage, changing the rotation speed and changing the time between pictures. Since the camera has to be on the whole time that a movie is made, the internal batteries won't last long enough. So I also made a secondary power supply using a second LM338 voltage regulator that supplies a fixed 5 volt supply to run the camera off the car battery. A link to Texas Instruments: Voltage Regulator link

So here's a picture of the components. A tripod to hold the camera, the mounting block/power supply, 12 volt battery, camera.

 Here it is in operation:

Once you take a series of pictures they have to be assembled into a movie. Lots of freeware is available to do that. I used A freeware version of Video Velocity from Candylabs. Here's their website: Candy Labs Software . The freeware is limited in what it can do, but it OK to assemble a simple video. I took about 1200 photos over a 3 hour period at the OMSI Paleo lab showing Bernie's rock as we worked on it. It's pretty boring but it shows what can be done. 

X-Rays of the Fossil Jaw

X-Rays of the fossil jaw

Dan O'Loughlin of the NARG group, who is a veterinarian, has been nice enough to try to X-ray a jaw fragment that has teeth in it. It turns out that 'how teeth are connected to the jaw bone' is an important criteria in the classification of animals. Here's a link to a web article: http://qilong.wordpress.com/2010/07/22/tooth-implantation-pit2/ and of course there is a lot more info available. 

First of all, here's a picture of the jaw fragment in question: 

It has nice teeth, well connected into the jaw. I picked it since the teeth in the skull look exactly like this, so we know this fragment and the skull go together. 

Next, Dan took X-rays using several different settings of time, intensity and wavelength. A few are attached:

Finally, I took one of the best photographs and tried to manipulate it so as to improve the contrast around the tooth root which is important for this classification: 

 Picture manipulated to improve root contrast:

Even after all this not much can be seen. This can be because the normal tissue space occupied by ligaments in living organisms is all filled with minerals from the matrix - in this case calcium carbonate (limestone). If we need more data another analysis is needed - perhaps at the synchrotron facility at the U of Texas in Austin! 

Too Many Bones = Multiple Individuals

I think I've noted before that we seem to have a lot of limb bones for the amount of rock we have excavated. The first limb bone excavated, which bridged three blocks, was a nice Humerus or Femur which proved to be typical of all the limb bones. Part of this bone actually rolled free during the roadcut excavation, and was recovered by Richard Kimbell (Thanks Richard!).

It has hollow ends, a central marrow (seen in the broken surfaces in the middle) and a narrow center D-shaped shaft without a flange. During the summer we recovered a similar bone, but it was slightly shorter. It was also a mirror-image, so it had to come from the other side of the animal. The length is not due to broken ends: both bones have very thin edges at the very ends. 

So one possibility is that both  limb bones are from the same animal. In this case it would have to be a pathological bone ( one shorter than the other) or a case of front humerus / back femur being identical bones. Both cases are difficult to believe. The alternative is two animals of different ages, both juveniles at death, each contributing one bone.
But the story is not over! Here's the top of the skull with yet another humerus/femur to be removed to allow access to the skull.

This is the third bone in the series. This one is from the same side of the animal as the smaller bone above, but is smaller yet. It is also significantly more gracile (thinner) So we now have a series of three bones, progressive sizes, the large one from one side of the body and the two smaller ones from the same side. All 3 bones have been within 12 inches of each other in the block.

Now it's pretty sure we don't have three bones from the same animal unless we have a pathological condition. The bones have a wonderful progression of growth, well shaped, but all 3 still have hollow ends. The simplest explanation, though it is still unbelievable, is that we have THREE individuals of the same species, differing in ages, that died together while still juveniles!  Even in the case that two bones are from one animal (front/back) we still have TWO individuals of the same species. Combined with the fact we have two types of backbones, this means we have three or four animals mixed up in this collection of bones. What a host of questions come to mind - mass stranding of a family group, sexual dimorphism, schooling behavior, etc. Remember we have a mass stranding of Shonasaurus in Nevada from the Triassic. Perhaps this is similar behavior? 

Comments are always welcome. Sincerely, Greg Carr

Fool me once, Shame on you... Fool me twice, Shame on me...

Well, it looks like the skull IS the skull of an Ichthyosaur - or at least a reptile and not an amphibian. We've excavated along the jaw line and found out that the hole we thought was the orbit (where the eyeball goes) isn't. Instead, the orbit may be further back. It now appears that the back end of the skull is broken off as well. So apparently we have a skull from a Euriapsid or Diapsid animal, with Fenestras  behind the orbit and the Naris (nostril hole) in front. Or not.  However, I am still uncomfortable with this layout. The orbit is too small for an ichthyosaur, and the naris (nostril) is too large.
Maybe the skull is actually like this as a Reptile and not an Ichthyosaur:

Or maybe it's like a crocodile:

 I think it's best to reserve judgement as this animal has already fooled us at least once, and will probably do so again. And we really will need a knowledgeable person to evaluate this skull when it's excavated and prepared.

We also have complications of the limb bones which I'll talk about next post. All the excavated limb bones of this animal have nice round or "D" sections in the middle. But even the oldest Ichthyosaurs have 'flanges' on the Humerus and Femur which these bones lack. And the bones that would be in the lower limbs and hands are  much too elongated and 'finger' shaped for Ichthyosaurs who's paddle bones resemble round or faceted disks instead of our finger bones.

Anyway, enjoy the teeth and details of this part of the skull.

Sincerely, Greg Carr

Lots of Nautiloids

One thing we have found a LOT of is Nautiloids. By my count there are currently 8 large and many more small Nautiloids (chambered Nautilus) showing on the surface of this block, and I've already removed three and destroyed a fourth that was on the skull. We have two types - the coiled ones and the straight ones (Orthocones). I really wonder what would cause such a concentration of Nautiloids? My first thought is a feeding frenzy over the dead carcass of the Ichthyosaur. Or maybe a mass die-off after mass spawning? Squids do this, though the current chambered nautilus does not as far as I can tell. Anybody familiar with the habits of Triassic Nautiloids?

I just got done removing the largest and best of them from right next to the skull.
Here's a picture of the side of the Nautiloid with two limb bones in front of it. First I have to remove the two limb bones: they will be in a later post after they are prepared. I can tell they have hollow ends like all the other limb bones.

After I've removed the two limb bones, another nautiloid is revealed. This one appears to be crushed, and only part of it came out initially. I'll try to get more of it out later.

 Here's the really nice Nautiloid, removed and glued back together. The top part came off months ago and we've been saving it safely to put back on.

 Finally, here's the two Nautiloids I removed today. The larger one is complete - the complete shell is there. It's the size of typical souvenir shells sold in shops - 5 inches across. Some of it is really shell, some of what shows is merely the internal mold of the inside of the shell. The shell material seems to want to stick to the external matrix, not the inside fill. Murphy's Law, I guess.

The smaller piece of Nautiloid clearly shows the siphuncle- the internal tube passage from one chamber to the other. Now that the large Nautiloid is out of the way, we can get at the deep part of theback of the skull. From a preliminary look it appears to be split completely front to back down the middle, and we only have one-half. However, this is actually excellent as it will reveal lots of the internal anatomy when prepared. I'll update information about the skull in the next post - major change in our concepts coming! 

Still more teeth - on a palate or a mandible

This post covers one more bone recovered that contains teeth. This makes a total of 4 bones with teeth - a jaw fragment with teeth in sockets, a skull, a jaw fragment with a trench where teeth were, and now a long convoluted bone with small teeth in the center.
Originally I thought the bone might be a clavicle of the Ichthyosaur, since we have most of the other shoulder girdle bones. The first side exposed had no indication of the teeth - they were on the rock side (inside) of the bone.

However, the first sign of teeth occurred as we were cutting around the backside of the bone to free it from the rock. We cut it quite deeply so as to not damage anything, since we didn't know what we had. Since the bone was long and thin, the side without rock was coated with latex and mounted in plaster. This provides enough support that even thin and fragile bones can be successfully prepared without breaking them to bits.
Here's the front side after complete removal from the large block and preparation:

 And here's the back side, showing the teeth. 

Here is is zoomed in to the teeth area which is about  4.5 x 1 cm. It probably continued to the right, but the bone is now broken. These teeth sure are cute, but were a real problem to prepare. Most of the teeth crowns are intact, though I did lose one or two of the very small ones during the preparation process. Note that these teeth crowns were broken in life. I don't know if they were mandible teeth, which would have been from the left side, or it they are palate teeth (amphibians have & had teeth sticking down from the hard palate). They look like they are in sockets, multiple rows, so I'm guessing they are from an amphibian and not the Ichthyosaur. But they sure are a different scale - much smaller - from the socketed teeth already prepared.

For your reference I've included pictures of the other jaws and teeth that we have found so far. They are much larger than the teeth on the featured bone above - the teeth in both pictures below are really about the same size.   

 Until next time, this is Greg Carr from OMSI Paleo lab. I hope your holidays were happy and blessed.

Jaw Fragments and Shoulder Girdle

Jaw Fragments and Shoulder Girdle

We have for your viewing pleasure a couple of unrelated items. Back in July I posted about a jaw fragment with teeth that we found. We now have a second jaw fragment, with tooth sockets. These two jaws are not from the same type of animal. In one, the teeth are in separate sockets  - called "Thecodont". The other, the teeth (now missing) are in a groove with equal sides - called "Aulacodont".

The Aulacodont is most typical in Ichthyosaurs except for the Triassic varieties of Shonisaurus and Cysbospondylus which are Theocodont. The giant amphibians have teeth that are in individual sockets - Theocodont. So who's jaws do we have above? 

The skull we have, amphibian, has teeth present but the details of the jaw are not clear since they haven't been prepared yet. The teeth in the jaw look like the teeth in the picture above.  So I'm betting the jaw fragment with teeth belong to the amphibian, and the jaw with the groove is from the Ichthyosaur. This contradicts my posting of July 26th where I thought we had the Ichthyosaur jaw. We keep learning new things and finding new bones all the time with this specimen! 

As a second item, we have now fully prepared what looks like a Scapula. Previously we had two bones that I believed to be Coracoids. We also have a humerus, or upper arm bone. We can fit all four bones together as they would have been in life. This scapula is thick at the part where all three bones fit together (the Glenoid Process) where the limb rotates. Otherwise, it is very thin about 1-3mm thick. This bone required a full plaster backing to complete the preparation. It came out very nicely - a great bone!. 

 We are still missing the clavicles (collar bones) but one bone is a strong candidate. 

We'll have it out in a couple of days so we should be able to see if it really is a clavicle.