Preparation of Marine Mammal Fossils from Point Reyes National Seashore: A Collaboration with John Day Fossil Beds National Monument

By Jennifer L. Cavin, Paleontology Lab Manager and Fossil Preparator, John Day Fossil Beds National Monument

Between the years 2008 and 2010, approximately 145 fossil specimens were collected from PORE lands and eventually placed into PORE museum collections. No field notes were available to describe the geology or geography of the collection sites. As part of a long-term curation agreement, the specimens were sent to the California Academy of Sciences (CAS) where a research scientist evaluated the material and recommended two specimens (potentially new species) be prepared from the surrounding rock. Because there are no trained preparators at PORE, the park and the NPS Paleontology Program reached out to John Day Fossil Beds National Monument (JODA) staff to develop a partnership.

“I know that myself, and the PORE resources staff, are very grateful for the expertise and support JODA staff have provided since we don't have any paleontologists at PORE,” said Virginia Bones, Museum Curator, Point Reyes National Seashore.

Fossil preparation is a unique skill set that requires specialized training. I earned a Master of Science in Paleontology at South Dakota School of Mines, focusing on fossil preparation. I have worked as a professional preparator for more than twenty years and have been filling the role as fossil preparator/lab manager for JODA since 2008. I work mainly on terrestrial mammals at JODA so I was thrilled to take on the challenge of preparing marine mammals.

In 2019, Vince Santucci, National Park Service Senior Paleontologist, contacted JODA’s Lead Paleontologist, Dr. Nicholas Famoso, to ask if our lab could prepare a porpoise skull for Point Reyes. The specimen (PORE 18933) arrived at JODA in December of 2019 in two pieces. From the initial condition description as recorded in the preparation record: “Bone is varied between beautiful flat, shiny black bone with wonderful separation and a more porous black bone that has little separation.”

Left: Ventral (bottom) left before preparation. Right: Dorsal (top) right before preparation.

Jennifer L. Cavin, Paleontology Lab Manager and Fossil Preparator, John Day Fossil Beds National Monument

Originally the contract between PORE and JODA would pay for 100 hours of my time to prepare the skull. The matrix was incredibly hard making its removal a slow process. Because I was unfamiliar with marine mammals, I contacted a friend who researches them in order to find out the most important details of the skull to uncover. I was told the periotic (bone surrounding the inner ear) was of particular significance as a diagnostic feature. I used an H-10 German airscribe by Stone Company to slowly remove the matrix from the skull. This is a medium sized scribe that has enough power to get through the hard matrix. I did find an intact periotic on one side of the skull. I switched to a more delicate airscribe, the MicroJack 1 by Paleo Tools, to detail out these bones.

After 100 hours of prep was complete, I felt I needed a little more time to finish the specimen. PORE gave us 40 more hours of salary to finish the job. During this time, I finished the smaller piece of skull material and found that it fit onto the larger piece. I glued the two specimens together using B-15 McGean, thus making the skull more complete.

Left: Ventral left after preparation. Right: Dorsal right after preparation.

Jennifer L. Cavin, Paleontology Lab Manager and Fossil Preparator, John Day Fossil Beds National Monument

In 2023, our lab was contacted again to see if we could prepare a beaked whale skull from the same collection at PORE. This time 80 hours were set aside to complete the project. The skull arrived at JODA in two pieces, and the following was recorded in its preparation record condition description: “The skull (PORE 18938) is in good condition and has some tan colored matrix adhered to it. The rostrum [beak] (PORE 18934) is broken and glued back together from 7 different pieces. This repair work was done before the specimen arrived at JODA.”

Left: Skull before preparation. Right: Beak before preparation.

Jennifer L. Cavin, Paleontology Lab Manager and Fossil Preparator, John Day Fossil Beds National Monument

From my previous work on the fossil porpoise, I knew that finding the periotic should be my first order of business. I used a MicroJack 6 by Paleo Tools to remove matrix from the main skull piece. The skull seemed strangely shaped to me, and I was having trouble orienting the skull bones in my mind. Eventually, I found a periotic which confirmed the dorsal/ventral orientation. Once again, only one set of ear bones was present. I continued to remove matrix and came across a bone that didn’t seem to belong to the skull. I reached out to someone who studied marine mammals and was told it looked like a hyoid bone (a bone found in the throat). As recommended, I isolated and removed as much of it as I could; there was one section that was too attached to the skull to safely remove. I then used the same airscribe to remove matrix from the rostrum piece. I attempted to fit the two pieces together so I could glue them, but there were not enough points of contact for the glue to hold. In the end, I spent 80 hours of work uncovering the periotic, removing the hyoid bone, and revealing as much of the skull and rostrum pieces as possible.

Left: Skull after preparation. Right: Beak after preparation.

Jennifer L. Cavin, Paleontology Lab Manager and Fossil Preparator, John Day Fossil Beds National Monument

Because of the collaboration and professional support between PORE and JODA, these two important specimens are now available for detailed study. Preliminary consultations with marine mammal researchers have suggested they are most likely new fossil species to science. Although the fossil record of porpoise is quite extensive (Racicot, 2014), PORE 18933 has the potential to shed light on the evolution, anatomy, biogeography and diversity of this group of mammals. The second skull (PORE 18938/18934) seems to be from the family of Ziphiidae (beaked whales). Extant members of this family of whales are not well known because of their “deep-sea habitat, reclusive behavior, and low abundance” (Bianucci et al., 2008). In contrast, fossil specimens of beaked whales have become abundant during the last decade, retrieved by fishing deep sea floors (Bianucci et al., 2013). The information gained from PORE’s fossil specimen can help identify the paleo environment from which it was found as well as improve scientific understanding of these mysterious animals and their evolutionary relationships.

References

Bianucci, G., Post, K., and Lambert, O. 2008. Beaked whale mysteries revealed by seafloor fossils trawled off South Africa. South African Journal of Science 104 (3–4): 140–142.

Bianucci, G., Mijan, I., Lambert, O., Post, K., and Mateus, O. 2013. Bizarre fossil beaked whales (Odontoceti, Ziphiidae) fished from the Atlantic Ocean floor of the Iberian Peninsula. Geodiversitas 35 (1): 105–153.

Racicot, R. 2014. Fossil focus: Porpoises. Palaeontology Online 4, Article 10: 1–8.