The unexpected presence of furry-eared dwarf lemurs in Madagascar’s western highlands

Unexpectedly finding Mbola’s cousins out West

By: Marina Blanco & Lydia Greene

Collaborators: Sebastian Kraves & Ezequiel Alvarez-Saavedra (miniPCR bio); Toky Rakotoarinivo, Rova Ramaroson, & Josia Razafindramanana (IMPACT Madagascar); Fanomezana Ratsoavina (University of Antananarivo); Elaine Guevara (Duke University)

Our story starts in the forests of Tsinjoarivo. Sitting on the eastern side of Madagascar’s central highlands, Tsinjoarivo is a montane rainforest, meaning it is characteristically very cold and very wet. Back in 2006, our team started working at Tsinjoarivo and, using a simple marker gene, confirmed the presence of the furry-eared dwarf lemur (Cheirogaleus crossleyi). You can learn more about this adventure, and follow in our footsteps, in our Conservation Genetics Lab.

Fast forward to May 2024. We had begun a new collaboration with an NGO called IMPACT Madagascar. IMPACT Madagascar manages several forest fragments on the western side of the central highlands. There, they protect endemic biodiversity while supporting local communities. Our collaboration with IMPACT is to learn more about the lemurs that live in the forests they manage. Together, we planned a trip to a site called Mahajeby to study the sifakas and mouse lemurs. But once there, we serendipitously stumbled upon what looked like a furry-eared dwarf lemur. See the photo. We were perplexed.

What was this lemur doing there!? The western side of the highlands is very different from the eastern side. It’s much drier and warmer. The trees are totally different. Plus, the two “sides” of the highlands are separated by hundreds of kilometers of expansive grasslands. Could it really be the case that the same lemur species from Tsinjoarivo also lives in Mahajeby? But because May is at the beginning of the hibernation season and the lemurs are hard to study, we would have to wait for an answer.

[Our work] means that Mbola, Razafy, and Ihary from the eastern side of the highlands have close cousins on the western side, whom we named Toky, Gabbi, and Haja.

In October 2024, after the dwarf lemurs emerged from hibernation, we returned to Mahajeby. We also visited a site even farther west, called Ambohijanahary, where we also thought we could find dwarf lemurs. At both sites, our team was able to safely capture, sample, and release several dwarf lemurs. And wow did they look exactly like the furry-eared population from Tsinjoarivo! This field work was a big achievement, made possible only by the local knowledge and logistical infrastructure of the IMPACT Madagascar team.

But seeing the dwarf lemurs wasn’t enough. We needed genetics to confirm what our eyes were telling us.

We brought small tissue samples back to the capital city of Antananarivo, and there in the genetics laboratory in the Department of Animal Biodiversity, we extracted gDNA, amplified the mitochondrial cytochrome-b marker gene, and used an agarose gel to confirm our results. This lab work was a huge achievement, made possible only by the technology and reagents developed by miniPCR. Using their temperature-stable Master Mix, ladders & dyes, agarose tabs, thermocycler, and blueGel system streamlined the lab work and made it possible in a place with spotty electricity and water. We imported PCR product to the United States, submitted it for overnight sequencing.

Drumroll please…

The dwarf lemurs from Ambohijanahary and Mahajeby are exactly the very same furry-eared dwarf lemur species from Tsinjoarivo. (See the confirmatory phylogenetic tree.) This means that Mbola, Razafy, and Ihary from the eastern side of the highlands have close cousins on the western side, whom we named Toky, Gabbi, and Haja.

In conclusion….

These results highlight a big range expansion for the furry-eared dwarf lemur. We’ve also confirmed their presence even farther south in the highlands, at a site called Itremo. This means that this species is widely distributed across the central highlands, from north to south and east to west, and may mean a change to their endangerment status. Our methods also demonstrate that it’s possible to go from new samples (October) to confirmed species (December) in as little as a few weeks. This could dramatically speed up our ability to inventory and catalogue the biodiversity of new and understudied Protected Areas and inform site Managers for their conservation planning.

In the coming years, we hope to determine the full range of this species by surveying sites even farther north and south. Stay tuned!

Related resources:

• Conservation Genetics Lab: Discovering Lemur Diversity
• Video: The lemurs of Madagacar
• Studying genomes in the Madagascar forest