Today’s Fossil Friday post is on the dentary, or lower jaw bone, of a turtle (possibly Rhinoclemmys panamaensis) found at the Hodges Microsite locality in the Cucaracha Formation of the Panama Canal Basin. The fossil is early Miocene in age. Its large size is notable as it is larger than any modern species of Rhinoclemmys.
To learn more about this specimen, read the publication on its discovery here.
Cadena, E., Bourque, J., Rincon, A., Bloch, J.I., Jaramillo, C., and MacFadden, B. 2012 New Turtles (Chelonia) from the Late Eocene through Late Miocene of the Panama Canal Basin. Journal of Paleontology 86: 539-557. doi: 10.1666/11-106.1
Last week myself and the other interns took a field trip for two days to dig at the fossil site Thomas Farm, about an hour away from the museum here in Gainesville. The Thomas Farm site is from a comparable time frame (early Miocene) to our localities in Panama, and similarities in the fauna we find at each site show a biogeographic connection. Some examples of taxa that are in common are Parahippus, Floridatragulus, and Petauristodon.
Once at the site, we were given an introduction by Dr. Richard Hulbert. He told us that it used to be a large sinkhole, with some limestone caves. We talked about the sediment we would encounter and the types of fossils we would be finding. At Thomas Farm, they dig in 10 cm intervals, using a grid system to denote different squares. This is similar to how archaeological digs are done. Much of my fieldwork training comes from archaeological work, so I was very familiar with this and felt very comfortable digging this way. Various fossils were uncovered, and I even got to make my first jacket, which was for a mandible belonging to the camel Nothokemas.
The Nothokemas mandible in it’s jacket, after it had been cleaned by a volunteer.
Last week Justy, Nathan and myself headed to Duke to microCT scan fossils from the Panama Canal. Our main goal was to scan 71 fossil teeth belonging to various rodents, but we brought various other fossils along as well in case we had extra time. Overall we ended up scanning all 71 rodent teeth, 6 crab fossils, and various plants all from the canal sites. We even scanned some fossils for our personal research projects including a turtle skull and some sciurid postcrania.
When we arrived at Duke we met with Jimmy Thostenson, the engineer/technician in charge of running the scanner. Jimmy taught us how to position our fossils in the scanner, and then he set up the scanner and explained to us how it worked along the way. We queued up our specimens that would be scanned that day, and then left to explore campus. We returned later when they were finished scanning and checked the images to make sure they were looking good. At one point the center of rotation of our scans were off, so Jimmy taught us how to fix that. We then opened up each scan in Avizo and made a rough 3D image to make sure all was well. All of our scans ended up great!
Jimmy teaching us how to set up the scanner as Nathan and Justy look on.
The inside of the microCT scanner.
A Sciurid humerus from the Thomas Farm site in Florida, as it was being scanned.
And we’re back! A ton has happened since our last post. A huge group of our scientific partners at the University of Florida spent a week helping us collect fossils in Panamá. It was a wild time, with many folks downing Gatorades to stay hydrated in the blazing afternoon sun. Our combined efforts led to many fossil finds!
Jeremy with his humerus at Centenario 2 of the Cucaracha Formation
Anyhow, we are picking up where we left off. Last time, I described the heavy lifting we did to clean off one of our fossil localities and increase productivity. After we moved all of that sediment, Jeremy found the distal end of a humerus, possible from a fossil rhinoceros! We’ve continued down this path, moving to a new exposure of the Cucaracha Formation.
We just finished up a two-day project to revive our Centenario 6 locality – a fossil collection site where previous researchers have found unique fossils crucial to our understanding of American biogeography. The effort was literally massive. We must have busted up and shoveled nearly one thousand pounds of rocks and sediments with our rock hammers and pickaxes.
When we started…
In order to continue finding fossils, you have to work to expose layers where bones are most-concentrated – a result of the environmental conditions where the sediment was being laid down millions of years ago. This unit (Cucaracha, ~19 Ma) has produced incredible finds, including part of a jaw from a “bear-dog“ This a carnivorous mammal that originated in the “Old World”, and an Antracothere, which is an artiodactyl ungulate closely related to hippos and which is a sister taxa of whales. These fossils are critical clues, not only because fossil carnivores from this period are incredibly rare, but also because both of these fossils strongly link the mammals living in Panamá during the Miocene to those living contemporaneously in North America. The more evidence we find, the better our picture of Panamá and its role in the relationship between North and South America before the closure of the isthmus. Also, we’re looking to find some monkeys to better complete the picture.
PCP-PIRE intern Justy Alicea ready to be lifted to the jungle canopy.
After over a week in Panama, we are back in Gainesville, a little tanner and a little wiser. We learned a great deal on this trip and had a great time along the way. We were up at sunrise, worked as giant freighters passed up and down the canal all day and got to know Panama City and each other a little better.
The peaceful Sloth. One of the many locals encountered on our trip.
We traveled all day Saturday, but we officially started the trip off on Sunday with a tour of the jungle canopy, where we saw iguanas, monkeys and sloths, the group favorite. They were incredibly cute. We all wholeheartedly agreed we needed sloths in our lives. We then went to Punta Culebra, where we were able to get up close with local starfish, sea turtles, pelicans and rays.
The week itself was all work. We woke up and got ready to meet at 630 for breakfast, piled into a taxi van to the Smithsonian Tropical Research Institute (STRI) by 7, gathered equipment and field trucks, and drove to the canal. We were out in the field by 9. We’d spend all day digging, taking lunch around 12 and back at it until 3. Then we’d all jump back in the trucks covered in dirt and sweat and drive back to STRI to drop off our equipment, jump back in the taxi van, and be back at the hotel by 430. We’d all go shower and meet back up by 630 for dinner, where we’d go as a big group or break off into smaller groups depending on food preferences. We hung out together after dinner and then be in bed in time to do it all over again the next day.
Shrimp claw. You can just make out the pincers on the left side.
We found a lot of really nice fossils throughout the various localities we worked, from plants to sharks to horses and rhinos. It was intense, often heavy work. By noon the temperature was in the 80s-90s and if there was no breeze or cloud cover along the canal, fatigue set in quick. I almost learned the hard way that not even water is enough for dealing with that kind of heat and we kept electrolytic drinks handy at all times.
Some of the PCP-PIRE Spring break cohort in action.
We ended the trip with a visit to the newly opened BioMuseo on Friday and a walk around the old Spanish ruins of Casco Viejo on Saturday. The small, modern museum was great. Highly interactive, artistic and informative, the museum had some well designed halls. The “Panama-rama” and the great biotic interchange halls were especially impressive and they left a sense of wonder and drama about the impact of this thin stretch of land connecting 2 continents on the world. It perfectly summed up the mark this trip left on all of us.
The members of PCP PIRE that traveled to Panama for Spring Break have been collaborating with the field interns to collect plant, invertebrate and vertebrate fossils in several localities, both old and new. On Friday the group left the field early to visit the Biomuseo, a museum that focuses on the history and biodiversity of Panama. PCP PIRE, STRI and several other institutions have made contributions to the museum and it was the first time that many members of the Spring Break crew had seen the museum since its construction phase. The museum includes permanent and temporary galleries that explain the history of Panama: its geologic history and how the Isthmus came to be, its evolutionary history and biodiversity, and its cultural history and how humans have shaped the landscape of Panama. One temporary exhibit centered on contributions made by PCP PIRE and other institutions and included details of our discoveries so far as well as paleoart and casts of fossils made by members of the project. It was an amazing experience to visit the museum and see what we have discovered through the course of this project and how we are sharing our discoveries with the public.
The Spring Break group is wrapping up their fieldwork on Saturday and will be headed back to Florida on Sunday. Be sure to check back next week to hear from our museum interns about their experience in the field!
Photo of the Spring Break Panama Canal participants at the Canopy Crane.
This week 15 additional people descended on the Panama Canal – the University of Florida Spring Break crew has arrived. For the majority of participants, this is their first experience in Panama. We arrived Saturday afternoon and took Sunday as a tourist day to see the sights – the canopy crane and Punta Culebra were both great activities.
The first group is hooked up to the crane, which lifts them into the tree canopy.
The view from the crane.
This iguana was sunbathing in the treetops.
Vista at Punta Culebra.
Monday morning brought us to the Panama Canal. We depart our hotel at 7AM, get to the canal around 8:30, and work until 3:30. Quite a few fossils have been found – lots of new vertebrate, invertebrate, and paleobotanical samples are filling the lab at STRI!
Andrea De Renzis, Victor Perez, and Rachel Narducci search the Empirador Formation for sharks teeth and invertebrate marine fossils.
Dawn Mitchell searches for vertebrate fossils in the Las Cascadas Formation.
Museum Intern Will Tifft takes a swing at a difficult layer of Las Palmas along the Panama Canal.
These past few days in the prep lab I have been reconstructing the shell of a turtle known as Pleurodira sp. It has been very exciting to see the form of the shell after all the little pieces have been glued back together. I have also been working on my research, sketching the vein characters of my leaves for easy identification. Some of the specimens are so well preserved that it seems as if a modern leaf had been glued to the rock! And the detail of the veins under the microscope leaves me speechless! Every day that passes I become more amazed with my findings.
After a week of knowing my project, the paleobotany department was going to renew the student research exhibit, and I was asked to construct a poster on my research. I only had a few days to put my poster together, so I had to work fast, and last Friday it finally became part of the exhibit. In my poster I briefly explain the depositional history of the formation and describe the different morphotypes that were found in the collection (A digital copy of my poster will soon be available at this site www.flmnh.ufl.edu/research/student_poster.htm).
I am also excited for the upcoming trip to Panama, last Monday we had a meeting about the trip and learned that new fossilized leaves were discovered! I can’t wait to see them and compare them to the leaves form Tennessee.
This has been an incredibly exciting week for us out here in the field. Yesterday, we went to the Las Cascadas formation to collect sediment for washing and sieving. The quarry had been disappointing us recently, so we were just making a quick stop before we headed on to another locality. As we were showing a guest around the site, I had some free time and I began to poke around in the sediment. Almost immediately, I found a canine. Then another. I called over our supervisor Jorge Moreno so that he could take a look. Over the next few hours, the five of us uncovered more and more – a tooth here, some bone there – and by the time we were done, we had extracted what we believe to be the jaw of a camel! I’m waiting for some photos and conducting some additional research, but I promise I will post more about this soon!
Mystery bone! Just the tip is sticking out… We’re in the process of carefully removing the surrounding rock.
Today, our good luck followed us to the Centenario locality. Shortly after Jeremy and Sophie set about extracting the turtle carapaces they has discovered earlier this week, Jeremy uncovered a big chunk of shining black bone. We began our speculation… It seemed lodged in, like it continued for a bit into the matrix. Were we seeing an epiphysis (end) of a long bone? Could it be a crocodile quadrate (said Jorge)? We had to see more.
This conglomeratic layer had been good to us recently, so we decided to give it a good cleaning. With our machetes, shovels, hammers, and pickaxes, we chopped through and uprooted elephant grass before digging out sediment and exposing a horizontal bench above our find. “Opening the quarry” allows us to work from the top down, increasing access to this productive layer and making it easier to remove sediment without damaging our fossils. Check out the before and after pictures of our quarry below! Tomorrow, we’ll go back to Centenario and continue excavating the cluster of bone that we uncovered today. More updates to come!
BEFORE: Sediment and invasive elephant grass were covering a particularly productive layer.
After much digging, shoveling, and sweeping, we now have a clean bench that we can cut down into in our search for fossils.
Jorge Moreno Bernal and Fall 2014 Field Intern Lillian Pearson collecting a partial fossil peccary jaw covered in plaster. Photo courtesy of Hannah O’Neill.
Application Deadline: 5PM EST on March 9, 2015
Are you interested in a geology and paleontology? How about traveling to Central America and brushing up on your Spanish? Want to gain valuable field experience excavating fossils while enormous cargo ships pass by in the distance?
If so, then we have the perfect internship opportunity for you.
PCP-PIRE is currently accepting applications for its Summer 2015 cohort of field interns. The goal of the PCP-PIRE field internship program is to expose students to geoscience field and research techniques in an international setting as we make new fossil discoveries and refine the stratigraphy of the Panama Canal Basin. Interns are also encouraged to explore the culture and natural history of Panama and expand their outreach abilities in conveying the importance of geology and paleontology to the public.