Pteranodon sternbergi dig June, 1996 Copyright © 2000-2007 by Mike Everhart Updated 01/20/2007 LEFT: A full scale model of a Pteranodon sternbergi in flight at the Sternberg Museum of Natural History.

Late on the afternoon of June 1, 1996, my wife Pam found the wing bones of a large Pteranodon coming out about half way up the west side of 8 foot high, nearly vertical gully wall. The bones had apparently eroded out fairly recently but were already bleached to a light blue-gray color that contrasted well against the pale tan of the chalk. After digging back into the chalk about 6 inches, I uncovered most of the articulated upper wing bones (the humerus and the radius/ulna) of a fairly large Pteranodon. The “fresh”, un-weathered material was a reddish brown in color and was extremely fragile (comparable to two layers of broken egg shell held together with a soft, chalky matrix). The bones were oriented in the shape of a “V”, with the open end of the “V” pointing into the side of the gully. The fact that they were from a large individual (LEFT: humerus = approx. 24 cm in length), were still articulated, and by the their position, more or less indicated that the rest of the Pteranodon might still be in the chalk, made it easy for us to plan another trip to the site. .....

Pteranodons were a group of Late Cretaceous flying reptiles (not dinosaurs!) that were characteristically toothless and tail-less (they did have short tails), at least compared to pterodactyls from the Jurassic of Europe and elsewhere.  They grew to large size during the deposition of the Smoky Hill chalk (wingspreads of 7.5 m (25 ft) or more), and were even larger (e.g., Quetzacoatlus northropi) near the end of the Late Cretaceous. They were first discovered in the Smoky Hill Chalk by O.C. Marsh in 1870. Thousands of specimens have been collected since that time.

On June 29, we returned to the site about 8 AM to take advantage of as much of the cool morning temperature as possible. The first order of business was to start taking the overburden off of where the rest of the fossil was expected to be. There was about 3’ of hard tan chalk interbedded with calcite seams, covering an area of about 4’ by 6’ that needed to be removed.

Part of this was done right away in order to get a minimum working area and to expand the initial entry point to locate additional remains. The rest of the chalk was removed as needed over the next day and a half. All of the initial overburden removal was done with a heavy pick and flat bladed shovel (and lots of sweat!). The chalk was fairly hard and partially cross bedded, causing it to break up in mostly small, uneven pieces. This was hot work and not a lot of fun, so it was done in small increments.

The locality where the Pteranodon skull was found. A large, and relatively rare clam (Volviceramus undulatoplicatus) found nearby firmly establishes the age of this specimen as Early Santonian (about 85 million years).

Approximately 2-4” of chalk was left above the fossil at this point. This was removed slowly, with an ice pick and brush, and occasional, careful use of a rock hammer. As soon as I started working at the level where the original material was found, I encountered additional bone, including the distal portions of the radius / ulna that I had been unable to take out initially. This led to additional bones that were scattered randomly to the right (southwest) of the initial find. These included a complete humerus, a scapulo-coracoid, two cervical vertebrae and other wing bones, including most of a 1st phalanx that was 56 cm in length. These were exposed, coated with a mixture of Duco cement and acetone, photographed and then removed. The Duco cement hardens the bone but can be removed with acetone if necessary during final preparation. Better preservatives are now available but old habits are hard to break!

By early afternoon, another ridge of bone was encountered at the back (east side) of the excavation. As this was uncovered, it became apparent by the size and shape that we had found the lower jaw. Further excavation at the posterior end of the jaw showed additional bone above the upper surface of the jaw and eventually the entire skull was found to be in place, and still articulated with the lower jaw. The skull was laying on it’s left side, with the lower jaw closed. Working around the skull, we found several other wing bones, including one that went directly under the crest. Drawing adapted from Eaton, 1910.

By the time that the skull was cleared off, it was almost five o’clock and we knew that we were not going to get the remains out that day. We covered up the specimen and checked back into the motel for the night (a 25 mile drive to the nearest town).

Sunday was supposed to be even hotter, so we were back in the field by 7:45 AM. The Pteranodon skull was cleaned further in preparation for the application of more preservative and jacketing. At this point, the last of the overburden to the east and south of the skull had to be removed in order to allow for jacketing of the skull and turning of the jacket.

Several of the wing bones around the skull were removed individually in order to cut down on the size (and weight) of the final jacket. In the process, a group of small bone pieces was isolated at the back of the skull. Field examination showed one wing claw mixed in with other material. Two more disarticulated cervical vertebrae (third and fourth?) were also found at the back of the skull and removed. It appeared that the atlas/axis vertebrae were still connected to the base of the skull (at lower left, below)

Photo of the right side of the Pteranodon skull. The last 12 inches of the beak is missing and probably inside a down faulted block at the edge of the gully. Wing bones frame the front, back and across the top of the skull.

At this point, the block containing the skull was isolated by digging a four inch cut completely around it. Once this was done, the block was undercut slightly to allow the jacket material to fill in and support as much of the chalk as possible, and to find a seam in the chalk that could be used to separate the block from the matrix. Once the undercut was completed, the exposed bones of the skull were soaked with the Duco Cement / acetone mixture and allowed to dry.

Once the preservative had dried, aluminum foil was placed over the block to prevent the jacketing foam from contacting the specimen. A 4” wide piece of 1/4” plywood was added along the length of the skull to reinforce the jacket. Then a temporary form for the jacket was made of cardboard, placed around the block containing the skull, and supported with pieces of broken chalk. A two part mixture of isocyanate foam was prepared and poured into the form. The foam expands and cures in about half an hour, producing a hard, yet light jacket for the specimen.

The edge of a large clam shell called Volviceramus undulatoplicatus that was eroding from the chalk nearby. Since this species is only found in a very limited biostratigraphic zone in the chalk, the age of the Pteranodon was established at early Santonian or about 85 million years ago.

When the jacket had cured and the form removed, thin chisels and metal blades were driven under the block to break it free of the matrix. Once it was loosened, the block was turned over so that it was now upside down and resting on the ‘top’ of the foam jacket. It was then carried about 50 yards to our field vehicle and transported home for further preparation. We left the field about 1 PM on Sunday, feeling pretty good about our efforts. After getting the specimen home, I removed the chalk covering the lower side of the skull and began the delicate work of cleaning up th bones.

UPDATE ..........almost two years later.........May, 1998. A long delayed preparation of the skull indicated that our Pteranodon was a young male of the species, Pteranodon sternbergi. This was confirmed after examination by Dr. Chris Bennett, then at KU. The photo above shows the nearly complete cleaning of the skull and associated wing bones. Interestingly, the only bones from below the shoulders that have been found so far are several tarsals and a foot claw that were lying under the beak of the animal.

In June, 1998, we made a final trip to the site, hoping to collect additional material. After removing a lot of over-burden, however, we were only able to find one more bone, the missing right scapulo-coracoid.  In 1999, the specimen CMC VP 7203) was donated to the Cincinnati Museum of Natural History and Science where it was prepared for exhibition.

In February, 2003, I visited the Cincinnati Museum Center where the specimen (CMC VP 7203) was on display.

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Credits: The line drawings of Pteranodon sternbergi were adapted from the book, Kansas Geology, Rex Buchanan, Ed., University Press of Kansas, 1984.

Email comments and / or questions to Mike Everhart

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