A Squalodontid Success
On a beach in Piña, Panama the tide is rolling out. Faint outlines of skeletal remains rise above the sand. Smithsonian scientists Nicholas Pyenson and Aaron O'Dea along with a team of students descend upon the beach. Their mission: to excavate the remains of a whale from the extinct group Squalodontidae, commonly known as "shark-toothed dolphins."
Before they remove the fossil, they must encase it in a plaster jacket. It's a process that can take up to two days. But they are racing the tide and have just four hours to remove the fossil. Will they make it?
Researchers Prepare for a Long Day in the Field
Before heading out to the fossil locality in Piña, Panama on the Caribbean coast, the team of researchers have a full breakfast at a cantina by the side of the road: roasted chicken, plantains, and some coffee.
Fish Skeleton Discovery
The fossil squalodontid skull was located in the middle of the tidal environment in Panama, exposed to the eroding elements of surf, sun, sand and waves. When the researchers arrived at the site the tide was just going out. They ambled out through the surf and spotted several other interesting fossils along the way: a partial whale skull, shark teeth, and a complete skeleton of a large fish, probably a close relative to a swordfish or a marlin. This fish skeleton was complete from nose to the tailfin. Shown here is segment of the tailfin against a 10cm ruler for scale.
Digging a Trench
The first thing the researchers did when they arrived on site was outline the general excavation area and take careful measurements of exposed fossils. Next, they applied acrylic glue to any exposed bone to help stabilize it. Then a small surface-layer cap of plaster bandages is applied to the skull to protect it from any errant whacks while digging. Finally, the digging begins, and scientists work to make a deep trench around the skull (shown here). The trench allows the researchers to apply a plaster bandage cap around the block of rock containing the fossils in order to extract the skull from the rocks in which it is entombed.
Securing the Fossil
After several hours of non-stop digging, the researchers have exposed a deep trench around the skull to begin applying a bigger plaster bandage cap around the block of rock containing the fossils. They use medial plaster bandages which consist of fabric already dipped in plaster -- this way they only have to add water to initiate the hardening process. The team applied around five layers of bandages to the entire surface; creating a cap around the block.
Dislodging the Fossil
After the plaster cap has dried and has created a cap around the block of rock containing the fossils, the team is ready to start swinging. Here a researcher takes large pick and strikes the base of the pedestal that the fossil caps sits upon. Done correctly, a few good whacks will dislodge the jacket, flip it, and remove it.
Excavating the Fossil
A few whacks later and the plaster jacket breaks free from the rocks it is entombed in, estimated to be about 6-7 million years old. The researchers from the Smithsonian's National Museum of Natural History and Smithsonian Tropical Research Institute will move the jacket to higher (and drier) ground to be labeled and hauled away.
Racing the Tide
The fossil squalodontid skull was located in the middle of the tidal environment in Panama, giving researchers the added challenge of racing the tide for the excavation. The team was successful in their efforts, conducting an excavation that would normally take two days in just four hours.
Panama Expedition Success
Dr. Nicholas Pyenson, Curator of Marine Mammal Fossils at the National Museum of Natural History poses with the safely encased fossils in their plaster jackets. Eventually the squalodontid, or "shark toothed whale" will make its way to the Smithsonian's National Museum of Natural History.