And so our adventure begins…
7:50am: everyone is anxiously waiting in the hotel lobby to embark on our first dig. The novices can be told from the veterans. We are bouncing on the balls of our feet while the veterans sit casually on the lobby couches. We should have taken point from them and conserved our energy! It’s already 80 degrees out with 90% humidity. It’s going to be a long day, but we’re all too excited to notice the weather.
First stop: Madden Dam
A cacophony of cicadas welcome us to the Madden Dam overlook. Madden Dam holds back Lake Alajuela, which is used to move ships through the locks from the Caribbean to the Pacific. The dam was fortified during WWII to prevent Japanese attacks from taking out the locks and crippling Allied Forces.
Finally, we arrive at Alajuela Lake! In an area that was once a Boy Scout camp, a national park now resides, guarding the treasures that we so ardently seek. We disembark from our transportation and begin the walk down to the lake. This short trek through the jungle becomes an adventure as we slip and slide down the slope.
Along the way, we are dazzled by a myriad of butterflies, including the stunning Blue Morpho Butterfly (Morpho amathonte). Emerging from the forest, we are greeted by calmly lapping water and bright red islands dotted throughout the lake.
Two dugout canoes await to take half of the group to the islands; the other half wI’ll remain on the mainland, scouting the shoreline.
As we climb into the dugouts, our excitement is slightly tempered by the uneven footing, as well as the rain drops that begin to come down. It would be a shame if our first day in the field was curtailed by a rainstorm. As we make it across the lake to the first island, the rain subsides, and takes the humidity and oppressing heat with it, ushering in a cool day, a nice breeze and renewing our excitement.
We land on the island and quickly begin to carefully scan the surface for fossils. We come across a few pieces of fossil wood, but not much more. We jump back into the canoes and head off to the next island. On the second island, we find more preserved wood as well as stone tool artifacts left over from the Clovis people that once inhabited the island.
After 2 hours of searching the islands, we head back to the mainland to connect with the rest of our group, hoping they had better luck.
Sticking to the main land:
While half of the group embarked on a grand adventure to the islands, those that stayed behind had a very productive morning.
Various shark teeth were found! The most impressive being a highly priced Megalodon tooth (Carcharocles megalodon) found by Heather Murphy.
Shark teeth are detectable thanks to their enamel that sparkles among the sediment. Along with the teeth, a large, intact crocodilian vertebra was found by Gretchen Miller. Unlike the shark teeth, which can be collected by picking them off the ground, the vertebra required a more delicate touch.
Gretchen and Jorge Moreno-Bernal, our STRI guide and expert for the day, placed a cast around the vertebra to protect it before carefully removing it from the ground.
Casting the fossil allows for better support to the bone, which could be fragmented. In this manner, we minimize the risk of damaging the fragile artifact. Once cast and removed from the site, it will be taken back to the STRI fossil preparation laboratories, where it will be carefully removed from the cast and prepared for further study.
Heading home for the night….but not quite yet….
As we head back to Panama City, we make a short pit stop at the STRI campus to listen to a few talks and discuss a couple of papers. Victor Perez, Ph.D student at the University of Florida, presented on Late Miocene Chondrichthyans of Lago Bayano while Gary Morgan, Vertebrate Paleontology curator at the New Mexico Museum of Natural History, regaled us with his finds on Late Miocene rodents in the same area. After the presentations, we discussed the prevailing theories of how and when the Isthmus of Panama actually arose. We concluded that there is not enough substantial evidence for any of us to conclude that any one theory is correct.
As we sign off for the evening, I leave you with a final request, read the attached papers, and leave a comment on your thoughts of how the Isthmus came to be. Maybe you can help us settle the argument between the two theories!
Paper 1: Middle Miocene closure of the Central American Seaway – Montes et al.
Paper 2: The battle for the Americas – Stone