Tuesday, June 16, 2009
Little Limbs — BJ's Current Specimen
I've been working on this specimen over a few months now, averaging 2.5 hours a week on Sunday afternoons in the UMNH prep lab. When I got this piece, the main outlines of the limbs on both sides of this specimen had been roughly exposed by someone else. I've exposed some additional bones and I'm currently working with a micro scribe under a low power stereo microscope to remove matrix and a rough crust that obscures bone detail. The matrix is quite hard, which is why I'm using an air tool on such a small specimen. The longest bone in the photo is approximately 10 cm long. There's another pair of long bones on the opposite side of this specimen. I'll get a photo of that side next Sunday.
As I recall when I got the specimen to work on, these are thought to be dromaeosaur hind limbs. I'm guessing that some of the new bone I've exposed is pelvis or pubis. I'm often surprised at how paleontologists can correctly identify bones that are barely visible, but on occasion the preparation reveals something unexpected.