Rediscovery on the Pacific Slope: Rainforest Partnership’s Final 2023 Research Expedition in the Tropical Andes


Zoe Whittall

December 19, 2023

“We are very interested in the Pacific slope. We don’t know what exists there,” Pablo told me.

RP herpetologist Pablo Venegas and the team were preparing for a 12 day expedition, the final one of the year, in search of new frog and lizard species. The expedition would take place in Bosque de Protección de Pagaibamba, a patch of cloud forest in an inter-Andean valley. They entered the Pagaibamba forest from two places: first, Pagaibamba, an area in the tropical Andes, and then, on the other side of the mountain, the Pacific slope of the forest, which is a different and vastly unexplored area about which little is known.

It is currently the rainy season, resulting in lush, misty rainforest scenes such as this one.

Nobody has ever entered this Pacific slope of the mountain for a research mission.

Pablo and the team will be the first. It is a very wet montane forest in the tropical Andes. The forest condition, as well as the variety of wildlife within the forest, in the Pacific slope is mostly unknown, and in planning the journey, the team were excited to see what types of new and different species would be found there. Setting out to study a place with so little prior research is a unique and exciting experience, and we are looking forward to the opportunity for RP to be able to do so.

As well as discovering new areas, there was another goal to this mission: to find a couple of species of frogs and lizards which were first discovered on a 2008 expedition and to take DNA samples so that they can be logged and categorized.

“I was in Pagaibamba, in this forest, in 2008,” Pablo said. "On that expedition, I found many unique frogs, including some new species, but I did not collect DNA samples. So, we need to return to this place and try to find the same frog species to take those DNA samples. We are especially hoping to find a relatively new species of Pristimantis, which we found in 2008, to get samples from that and record the frog’s call, so we can have the sound it makes on record too.”

They were also searching for the Pristimantis chimu, which was first discovered near Pagaibamba. Pablo wants to find this species of frog to try to compare it to other populations of the same species, which he suspects could in fact represent new species that are just quite similar. While the Pristimantis chimu is a rare and endemic species, in this location it is abundant as it thrives in cloud forest areas.

Pristimantis chimu

It is a beautiful Pristimantis frog with an orange belly, so Pablo and his team will be on the lookout for the flash of orange and hope to find more data about this special frog. The reason why Pablo wants to find it in this particular area is because the species here represents the original discovery, the first one to be found, which can be used as a basis of comparison for other similar species.

“It is the real Prisitmanis chimu!"

"It’s very important to take samples to understand if other populations are different frogs or in fact the same species,” Pablo explained.

The team are also looking for a specific species of lizard, a type of Petracola lizard on which little is known, and Pablo’s goal is to gather more data to try to understand this species as well.

Stay tuned for our next blog to learn whether the mission was a success!