New spider genus discovered in Madagascar

Our research team has discovered and described a completely new spider genus and species from Madagascar’s Marojejy National Park: Osmooka aphana.

This spider is exceptionally rare, only eight adult specimens are known worldwide. The first clue came from museum collections in San Francisco and Washington, D.C., where male and female specimens were found decades after they were collected. To learn more, the team from NIB and ZRC SAZU carried out two expeditions to northern Madagascar in 2022 and 2024, working closely with Malagasy collaborators. Even with intensive searching, only a handful of individuals were located.

Genomic analyses revealed a surprising result: the closest known relative of Osmooka is an Australian spider genus, Paraplectanoides. Together, these lineages form the family Paraplectanoididae, now expanded beyond a single genus. Divergence dating suggests their common ancestor lived about 57 million years ago, pointing to long-distance Cenozoic dispersal rather than ancient Gondwanan origins.

The discovery highlights both the extraordinary biodiversity of Madagascar and the ongoing need for taxonomic work on its little-known species. It also reshapes our understanding of spider evolution and biogeography.

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