Fossil Friday 10/30/2015: A crocodylian osteoderm

UF267030

UF 267030, an osteoderm of an unknown crocodylian. Photo © VP FLMNH.

This week’s Fossil Friday features an osteoderm of a crocodylian. This osteoderm was found at the Lirio East site of the Culebra Formation and is early Miocene in age. Osteoderms are bony plates that form in the dermal layers of the skin (dermal bones) and are found in many reptiles and amphibians. In crocodylians, many of these bony plates are embedded in the skin and act as a form of armor. Osteoderms are also heavily vascularized in modern crocodylians, allowing them to absorb heat when they are basking in the sun.

 

Last Week at the Canal-Learning to Make a Plaster Jacket

2015-10-13_10-08-07_495

Centenario Bridge looking up from the dig site

2015-10-13_07-30-48_732“It looks as if we have something here,” Jorge our boss exclaimed the minute we got to our Centenario dig site. I walked over and saw the tiny bit of black bone poking out of the ground. This is how it always starts, a little bit of black bone. Continue reading

Fossil Friday 10/23/15: A podocnemidid turtle

UF242111

UF 242111, the right second peripheral of an podocnemidid turtle (genus indeterminate). Photo © VP FLMNH.

This week’s Fossil Friday features the peripheral of a podocnemidid turtle! This specimen was found in El Lirio Norte of the Culebra Formation and is early Miocene in age. The family Podocnemididae belongs to the suborder Pleurodira. The most common depiction of turtles shows them pulling their heads into their shells in order to escape danger (suborder Cryptodira); however, pleurodires are distinct in that they hide by pulling their head and neck to the side under an overhang of their carapace.

Twist-necked_Turtle

The twist-necked turtle Platemys platycephala is also a pleurodire (family Chelidae). In this photo, the turtle has pulled its head to the side and glances out from under the overhang of its shell. Photo © http://www.birdphotos.com, taken from Wikimedia.

 

 

Gatún and Empire with the Invertebrate Crew

This trip to Panama has been a little different than normal – we have a group predominantly composed of invertebrate paleontologists and paleobotanists, but have few vertebrate paleontologists. Where do you go in Panama if you want to find invertebrate fossils? Well, you can’t go wrong with the Gatún Formation, which has enchanted malacologists (mollusc-workers) for over a century.

Panoramic photo of the San Judas locality, near the town of Sabanitas in Panama.

Panoramic photo of the San Judas locality, near the town of Sabanitas in Panama. Photo by C. Robins.

We headed to Gatún on Thursday. It was an incredibly muddy day, with thunder often rumbling in the background, but we were lucky to have a wonderful collecting day. We ended up with over 1,000 invertebrate fossils; mostly molluscs, but with a few decapods, too.

Post doc Adiël Klompmaker keeps his paleo-paper easily accessible for fossil-wrapping. Photo by C. Robins.

Post doc Adiël Klompmaker keeps his paleo-paper easily accessible for fossil-wrapping. Photo by C. Robins.

Turritellid gastropods dominate some areas of the Gatún.

Turritellid gastropods dominate some areas of the Gatún.

We tried out multiple localities within the Sabanitas area, but found many had become overgrown and inaccessible in the last few years. This is a constant issue in Panama, where the erosion rate is high and the plants are constantly reclaiming the open space.

We have Prof. Jon Hendricks with us on this trip. He is a specialist in cone shells, and has been working on their phylogeny. He uses UV light to see their color patterns, which have long-since vanished from our visible color palette. We managed to collect around 500 cone snails for him, which was about half of the day’s total haul! (That’s not a true representative of Gatún diversity.)

Dr. Jon Hendricks sorting his fossil cones after a long day in the field.

Dr. Jon Hendricks sorting his fossil cones after a long day in the field.

After a productive day in Gatún, today we stayed in the canal zone. We were able to access the Empire Locality, a locality full of decapods that had previously been within the construction zone, and thus inaccessible to collecting.

Collecting in the Panama Canal - the crabs are too good to pay attention to the scenery!

Collecting in the Panama Canal – the crabs are too good to pay attention to the scenery!

IMG_2469 (1)

Roger Portell and Adiël Klompmaker hunt for decapods alongside the Panama Canal.

An anteater even tried to help us find fossils. He quickly headed back into the vegetation. Photo by Adiël Klompmaker.

An anteater even tried to help us find fossils. He quickly headed back into the vegetation. Photo by Adiël Klompmaker.

Friday proved to be an incredibly hot day, and we almost welcomed the torrential downpour that arrived around 1PM. The excessive lightning, however, forced us in for an early end. Tomorrow (Saturday) is our final field day, which we will spend as a divided group – part of the group will hunt for crabs, and the museum interns will finally get a chance to test their vertebrate paleontology skills at a few canal sites!

Fossil Friday 10/9/15: Fossils from the Gatún Formation!

For this week’s Fossil Friday I am going to send you off to see what invertebrate paleontologists Jonathan Hendricks and Alex Kittle are finding in Panama! They are conducting fieldwork in Panama along with Cristina Robins, Adiël Klompmaker, Roger Portell, Nathan Jud, Chris Nelson and our museum interns! Follow the links below to check out Jonathan Hendricks’ and Alex Kittle’s Twitter accounts and see all of the fossils they have been finding in the Gatún Formation and other localities in Panama!

Jonathan Hendricks: https://twitter.com/deadsnails

Alex Kittle: https://twitter.com/fossilflorida

 

Dispatch from the field— Lake Alajuela with Nathan Jud

This is my fifth trip to Panama for paleontological field work. Since I started working with the project a little over a year ago, we have been collecting fossils along the shore of Lago Alajuela in Chagres National Park with more and more emphasis. One reason for this focus is that as the expansion of the Canal nears completion, it is important to identify other outcrops where we can collect important fossils. The Alajuela Formation is an exciting place to work because we find fossils of terrestrial vertebrates (exploration of the area started with the discovery of a gomphothere tooth), marine invertebrates, shark teeth, and fossil wood.

view across Lago Alajuela

view across Lago Alajuela

The fossils from the Alajuela Formation date to the mid-late Miocene and they tell us about the distribution of plants and animals leading up to the Great American Biotic Interchange. The Miocene lasted from 23 Million years ago to 5 Million years ago, but the Isthmus of Panama was fully formed only ~3.5 Million years ago, allowing animals to walk between the continents for the first time. Druing all of the Miocene, the Central American Seaway was a major barrier and only a few species managed to cross.

Fossil wood from Lago Alajuela

Fossil wood from Lago Alajuela

One of my roles in the project so far has been to document the diversity of plants in the Alajuela Formation that are known from the fossil woods. So far we have close to 100 specimens, and at least 30 different wood types (species). This is very diverse for a fossil wood assemblage, but probably what we should expect from a Neotropical forest. Several interns, including Chris Nelson, Carolyn Thornton, and Jeremy Dunham have played a role in understanding the Alajuela woods so far, and these three are on this trip.

Carolyn, Chris, and Jeremy at Lago Alajuela. Oct. 2015

Carolyn, Chris, and Jeremy at Lago Alajuela. Oct. 2015

I started the day with Chris, Carolyn, and Jeremy by collecting fossil wood for a project that Jeremy is working on. The rest of our group (nine more) walked north along the shore of the lake to a site where a fossil echinoid was collected a few months back. After about three hours we caught up with the invertebrate crew in a nice open area where we could have lunch and prospect a limestone outcrop.

Common Basilisk at the edge of the forest

Common Basilisk at the edge of the forest

Just as I sat down for a water break, post doc Adiel Klompmaker hollered out to me from a little farther down the shore “Nathan, you’re going to want to take a look at these!” I knew he must have found some plant remains, so I hurried over. As I arrived, I could see undulating laminae of fine-grained material covering the limestone, and Adiel explained that the pattern was probably produced by algae. He handed me rock he had just pulled from the algal deposit and on it was a fossil leaf with exceptionally well preserved venation!

Leaf fossil from Lago Alajuela

Leaf fossil from Lago Alajuela

Carolyn Thornton sitting on the algal deposit, pointing to a fossil leaf

Carolyn Thornton sitting on the ancient algal deposit, pointing to a fossil leaf

Leaf fossil at Lago Alajuela

Leaf fossil at Lago Alajuela

Adiel amassed a collection of more than a dozen leaves, and Chris and Carolyn identified the layer where Adiel found the first leaves and managed to collect more from nearby. In total, we collected ~50 leaves and leaf fragments before we started hearing thunder nearby and decided to pack up. The hike back to the cars was long and uphill through the forest.

Tropical forest on the hike back to the car

Tropical forest on the hike back to the car

I am excited to see these prepared back at the lab. Some of them seem to be three-dimensionally preserved, and perhaps the cellular structure of the mesophyll is intact! Perhaps we will find that the leaves belong to the same families as the fossil wood, and we might even find evidence of plant-animal interactions in the form of insect damage. I think we collected several different species, and I hope to make some preliminary estimates of paleoclimate using leaf physiognomy.

heading home

heading home

Fossil Friday 10/2/15: A prickly cockle

UF 220130

UF 220130, the prickly cockle Dallocardia baiterum. Photo © IVP FLMNH.

This week’s Fossil Friday feature is the prickly cockle Dallocardia baiterum. This bivalve specimen was found in the Gatún Formation and is Late Miocene in age. This species is endemic to the Caribbean side of Panama.

To learn more about this specimen, read the Fossils of Panama post about it here.

Field Training at the University of Florida!

Hi all,

I am the new 2015-2016 PCP-PIRE field intern! A little about me: My name is Dipa Desai, and I came to join the PCP-PIRE project through my interest in paleoclimate science. I arrived in Gainesville last week, and have since been training with the paleobotany, invertebrate paleontology, and vertebrate paleontology departments here at UF.

The technique I’ve been learning are ways to prepare the fossils for research. In the paleobotany lab, I helped Nathan, the resident paleobotany expert and post-doc, to create acetate peels of the cross-sections of calcitic mudstone chock full of fossilized plant material. As you can see, the peel below shows a cross-section of a Parinari fruit pit, similar to a peach pit, as well as several other sections of fossilized wood and seeds.

IMG_20151002_094119_906[1]In the vertebrate paleontology lab, I learned how to prep the fossils as they come back from the field. Similar to a puzzle, I glued broken bone fragments back into complete specimens using B-72, a mild adhesive that is reversible with acetone. I also worked on removing larger bones from the plaster jackets that paleontologists use to protect the fossil en route to the lab. I used acetone to wet the matrix surrounding the bone, and gingerly brushed it off to slowly uncover more of the fossil. This particular fossil is from Thomas Farm locality in Florida, but it still gave me a good sense of how to prepare some the vertebrates I will be excavating out of Panama! IMG_20150929_132640[1]IMG_20151002_092113_508[1]In invertebrate paleontology, I created silicone molds of fossils that were preserved as internal casts. Aly and I created clay dams around the targeted cast, and poured silicone into it and let it set. The following day, we peeled the silicone molds off to reveal a 3D cast of the fossil! Here is an example of one Aly did today:IMG_20151002_095834_470[1]I definitely learned a lot these past two weeks, and I’m excited to take these skills to the field!