Uncovering new lineages in the Sunda pangolin () with museum mitogenomics.

Accurately identifying evolutionarily significant units (ESUs) is crucial for conservation planning, especially for species like pangolins threatened by overhunting and habitat loss. ESUs help categorize different pangolin populations, aiding in understanding their genetic diversity and distribution, which is vital for targeted conservation efforts. This research generated mitochondrial genomes from historical museum specimens of Sunda pangolins () from underrepresented locations, uncovering a new evolutionary lineage from the Mentawai Islands that diverged from Indochina and west Sundaland populations around 760 000 years ago. This population thereby represents a divergent ESU with a small distribution, important for conservation planning. The novel sequences provide resources for forensic labs tracing the origin of confiscated scales and shed light into the potential distribution of the 'mysterious pangolin'. Additionally, this research confirmed the presence of the two major lineages in Java and extended the known distribution of the eastern clade to Bali and East Kalimantan. Our findings potentially suggest a recent bottleneck and postglacial expansion of pangolins across Indochina and west Sundaland. Further investigation with genomic and morphological evidence, contact area sampling and type sequencing will be required to evaluate the taxonomic status of different lineages and .