Panama Fossils Help Unlock Mystery Of How Frogs Got Their Form

Colombian researcher María Camila Vallejo-Pareja is using fossil frogs from millions of years ago in order to understand the form and distribution of the vast diversity of frogs found in Central America today.

Vallejo-Pareja, who is currently a PhD candidate at the Department of Biology and Florida Museum of Natural History (FLMNH) at the University of Florida says the fossils had been unearthed during the expansion of the Panama Canal over 10 years ago.

“One of the biggest challenges of working with fossil frogs is that frogs are usually very small and their bones break very easily,” she says, adding that frog skeletons are relatively difficult to study because they are so small and brittle.

“That is problematic, because fossils will break (as any fossil will!), but the more problematic thing is finding comparative material,” Vallejo-Pareja says.

She says that the skeletons of frogs, especially the smallest ones, are difficult to find in museum collections but now it is easier than ever as powerful new imaging machines use computed tomography scanning (CT-scans) to render 3-D portraits of fossil creatures.

“The biggest opportunity is that resources as CT-scans of many species of frogs are now available and these have become my main source of comparison,” she says.

Vallejo-Pareja says that without CT-scanned fossils as a reference, it would be even more challenging to approach questions as the ones she is interested in.

“Studying these fossils is very important because frogs are a very diverse group today, especially in Central America, and we don’t know a lot about their morphological evolution and their biogeography,” she says, “Most of what we know is based on other methodologies, like molecular phylogenetics, and fossils are the direct evidence we are missing.”

Eureka Moment

Vallejo-Pareja grew up between the cities of Bogota and Medellin in Colombia and says her Eureka moment came during the long bus rides across a wide range of ecosystems.

“I was amazed by how much everything changed from being in Bogota, then going up the mountains to a cooler place and then heading down to Honda and La Dorada to be in one of the places that I will always picture in my head as the hottest places on earth,” she says, “After that, I wanted to be in nature and study nature.”

During her undergraduate degree in Biology at the Universidad Nacional de Colombia in Bogota, Vallejo-Pareja initially focused on botany.

“I changed to living mammals and then to fossils mammals after starting a class project in comparative anatomy and then for my last semester of my undergrad I joined some paleontology expeditions with STRI (Smithsonian Tropical Research Institute),” she says, adding that she has had a wide-range of experiences since then.

“Living in so many different cities and countries has been challenging but also amazing,” she says, “as was doing all this journey with my daughter who was born when I was an undergrad.”

Another Colombian researcher studying fossils is Dirley Cortes Parra.

Cortés, a researcher at Canada’s McGill University, Panama’s Smithsonian Tropical Research Institute and Colombia’s Paleontological Research Center, described a new ichthyosaur, Kyhytysuka sachicarum, from her hometown of Villa de Leyva.