Dispatches From South Dakota: Willie The Dimetrodon [Day 4]

Today’s post is from Michele Whisenhunt, a volunteer on the Museum’s paleontology team. She’ll be sharing photos with us while the team is at the Black Hills Institute, prepping Willie, the Dimetrodon the team discovered. Missed the team’s first dispatches? Day 1, Day 2 and Day 3

All work and no fun makes for a dull paleo preparer, soooo Mary Anderson, Pat Greenfield and I headed out early this beautiful morning for Custer State Park and a 14 mile drive where the buffalo and the pronghorn play. Autumn has hit in the Black Hills but the wildlife was worth the drive not to mention a glorious day. South Dakota is beautiful in so many ways.

Buffalo on the range

Arriving early afternoon for prep work at the BHI our direction turned to beginning the bone cleaning under Dr. Bakker’s direction and the microscope.

Precise fossil cleaning

After experimenting different methods of cleaning, a recipe was found. A vinegar bath gave the desired results.

Willie's leg
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Bernt under the magnified visor uncovers and cleans the most compete lower jaw of the Judy block, Trimerorhachis or Panzer Mudpuppy.

Jawbone

Tomorrow will be the beginning of many days prepping thousands of bones to complete Dimetrodon for his 2012 premiere in the new paleo hall.

Dispatches From South Dakota: Willie The Dimetrodon [Day 3]

Today’s post is from Michele Whisenhunt, a volunteer on the Museum’s paleontology team. She’ll be sharing photos with us while the team is at the Black Hills Institute, prepping Willie, the Dimetrodon the team discovered. Missed the team’s first dispatches? Day 1 and Day 2

It’s a beautiful and busy day in the neighborhood of Hill City, South Dakota

When we arrive to the prep lab there is activity everywhere with the Black Hills employees working on our new saber tooth cats, Xenosmilus and Smiledon some of the most fearless to roam. It is interesting to work side by side with the best in their field specializing in the finest fossils and fossil replicas.

Dr. Bakker instructs Mary Anderson, after finding the floating rib, to clean the rib bone and she uncovers a bite mark. Hallelujah, hallelujah! Everyone gathers to see the bite under the microscope.

Uncovered Bite Mark
Uncovered Bite Mark.

Kathy Zoehfeld has uncovered unknown rib in her skull jacket and she will continue working to uncover the pieces of skull.

Bernt Pettersson and Pat Greenfield faithfully work on the Judy Block, a huge Trimerorhachis block, named after the owner Judy, with Bernt uncovering a jaw with skin inside the lower jaw.

Marce Stayer and I are carefully pulling anterior and posterior spines. We’ll keep you posted daily as the work progresses.

HIPS HIPS HURRAY! [Dimetrodon Fossil Update]

Your HMNS field crew and lab staff score the missing pelvis!

Willie the Dimetrodon continues to command the attention of your Paleo Dept. personnel. In May through June, David Temple led an intrepid crew who gently lifted the plaster jacket containing Willie’s torso, shoulder and rump. Local ranchers Donny Gale and Gary Max Coltharp once again generously donated their time and machinery – especially useful was the Coltharp front-loader named “Lola.”

But still – though Willie is among the very finest D’dons anywhere, he had a pelvic deficit. Check out this hip diagram.

CB-WilliHipsEdge

Willie’s sacral ribs are there, the parts of the vertebral column that hold the hips. However, the hip bones themselves are still missing. Probably some hungry scavenger came by and bit these meaty bits off (one rib was twisted out of place too  and the lower left shoulder had some bite marks).

“Locality Edge” comes to the rescue. Discovered by a local science teacher four years ago, Locality Edge is an awesome outcrop of badlands, full of tortuous arroyos, box canyons and spires of red rock. The strata here are just a bit later than our Craddock Bone Bed and about a mile away. We removed a pelvis and set it in a drawer.

c-Willi-Edge-Pelvissmall

We did note that this set of pelvic bones was unusual – the shape was not distorted by the tons of rock that had buried it. Most of the time the burial layers flatten out natural curves of the upper bone, the ilium, and the wide lower bones, pubis & ischium. The Edge pelvis miraculously survived 285 million years under the rock layers. The lower bones kept the strong inward curve that the living animal had.

c-williedgevaronicasmll

The thought erupted in our minds: Could the Edge pelvis fit our Willie? Was it big enough??

Was it the correct species? We took the pelvis out of its museum tray and I brought it to the small but excellent prep lab at the Morrison Museum in Colorado (located a short drive from the famous Coors Brewery). The Morrison Museum generously opens its facilities for special Houston projects. Thirty hours of work later, with the assistance of three delicate pneumatic chisels, the outer form was cleaned of the rock (note the specimen in the skilled hands of a Morrison volunteer at right).

Superb!  And  when the inner surface of the ilium was placed next to Willie’s sacral rib, they clicked together precisely.  The size was perfect. So was the shape – the Edge specimen clearly came from the same species and the same body size.

Now, the pelvis is getting its final beauty-treatment at the skilled hands of volunteers at the Houston Museum prep lab.

Thus the contributions of a dozen volunteers and staff, plus two labs, has taken us one step further in getting Willie up on his feet, to delight and instruct  HMNS visitors.