Bhutan sequences complete the range-widemitochondrial phylogeography for red pandas, Ailurus fulgens

Red pandas, endangered mammals inhabiting an elongated montane region in south-central Asia, are up for IUCN Red List reassessment in 2025. One issue determining their status is species taxonomy. A recent mtDNA analysis compiled from several previous studies found they were united as one species, with weak support for a western sublineage and four haplogroups correlated with specific geographic regions. However, the crucial section of their midrange, Bhutan, was absent from that analysis. Now, sequences from red pandas in Bhutan have been added to that dataset and reanalyzed here. Phylogenetic analyses of these data, 91 haplotypes from [~]770 samples representing the entire red panda range, indicate again that red pandas are only one species, based on mtDNA. Bhutan hosted three of the previously defined four haplogroups and both putative subspecies (red and pink A. f. fulgens, orange A. f. styani). However, with the addition of the Bhutan missing link, the haplogroups graded even more into one another phylogeographically across their range, effectively displaying a genetic cline. Additionally, no large geographically specific subclade representing a subspecies was significantly supported within the large clade grouping all red pandas as one species. This study further reinforces the conservation priority of encouraging gene flow via protecting prime habitat areas internationally, connected by wildlife corridors and transboundary cooperation, allowing natural evolution for species survival.