Genetic analysis identifies new endangered baobab species in Madagascar

Researchers from the University of Wisconsin–Madison, the Missouri Botanical Garden, and Iowa State University have identified a new species of baobab tree endemic to northern Madagascar. The tree, named Adansonia bozy, was previously classified as part of the widespread species Adansonia za. The findings were published in the journal Taxon.

Lead author Nisa Karimi, who conducted the work for her doctoral research, said it remains surprising that basic taxonomic questions persist for such charismatic trees. Before this study, eight baobab species were recognized globally: one in Australia, one in mainland Africa, and six in Madagascar.

The team used targeted sequence capture, a genomic method that sequences hundreds of genes, to analyze tissue samples collected from remote Malagasy forests. Karimi noted that collecting samples required climbing massive trunks, often over 30 meters tall, to reach flowers that bloom for only one month each year and open after dusk.

Laboratory work was complicated by the high polysaccharide content in baobab leaves, which creates a slimy residue that fragments DNA. Karimi developed a protocol to extract high-quality genetic strands suitable for phylogenetic analysis.

The genetic data showed that northern populations formerly assigned to A. za are more closely related to two other northern Malagasy baobab species than to southern A. za populations. David Baum, a co-author who has studied baobabs for over 40 years, said the genetic evidence made the species distinction "crystal clear."

Based on its restricted range in northern Madagascar, the researchers assess A. bozy as endangered. Karimi said the formal recognition could unlock conservation funding that prioritizes threatened species. The reclassification also reduces the known range of A. za, potentially altering its conservation status.

Karimi emphasized that accurate taxonomy is a prerequisite for effective conservation. The team's results further suggest that another widespread species, Adansonia rubrostipa, may also comprise multiple distinct lineages. The researchers plan to continue sampling in remote regions to clarify Madagascar's baobab diversity.

The study was supported by the University of Wisconsin–Madison and collaborating institutions. The paper, "Phylogenomic analysis of Madagascar's baobabs reveals admixed populations and supports resurrection of a previously described species," appears in Taxon with DOI 10.1002/tax.70176.