Sunday, April 20, 2014

A New Lead on the Skull - Thalattosaur!

Several people from the 7th Annual Fossil Preparation Symposium looked at the pictures that I presented in my talk (see the last post) and suggested that the skull might belong to a Thalattosaur. This was a new type of animal to me. They lived only during the Triassic, their ancestry is unclear, and they evidently left no descendants into the Jurassic. Their name means "Sea Lizard" and they evidently were semi-aquatic, living on seashores. They evidently filled the role of seals or sea lions. Most of them were 1-2 meters long, while only the largest reached 3 or 4 meters. This makes our animal on the larger size of this group of animals. They have been found in Alaska, British Columbia, California, Europe and the best of all now come from China.

Looking at our skull, comparing it with various Thalattosaurs, there are a lot of similarities. Several species have a turned-down snout, some are even more pronounced than our skull which has a mild concave curve. Also, several skulls have an incomplete juglar, which is the bone under the opening in the skull. Our skull also has an incomplete bone. Here are some pictures: First our skull
Next some other skulls: 
Askeptosaurus Italicus
  Juvenile Anshunsaurus

Some Thalattosaurus limb bones also look like the ones in our block, since they had limbs with full legs and toes and not just paddles. However, all the backbones we've been finding don't really look like a Thalattosaur's at all. So either most of the backbones really do belong to an Ichthyosaur, or we have a Thalattosaur with Ichthyosaur-like backbones. Since there is apparently a lot of variations in the Thalattosaur Family, I'm betting it's the latter case. 

I am making a lot of progress in freeing the skull from the main block and it may come off in a couple of weeks. So far there are two limb bones, one coracoid and two nautiloids that will also have to be removed with it. They are all too close to the skull and will have to be worked off under a boom microscope. 

On a lighter note,  Jerry Dodson has had his grandkids over for week or so - they are from Virginia. So naturally he brought them over to OMSI and we let them prepare some fossils. They had a great time!!
Sincerely, Greg Carr

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