A spider discovered in Ecuador‘s Amazon in August 2025 has turned out to be both a new species and the first documented arachnid to mimic a fungus that typically kills its relatives. Alexander Griffin Bentley poked what appeared to be a cordyceps-infected mass during a field tour near Mera and watched it move.
The specimen bore two yellow and white tubercles—tendril-like structures—on its abdomen, features usually indicating fatal fungal infection. Bentley, a herpetologist with Fundación Waska Amazonía, posted images to iNaturalist, where users suggested the spider was mimicking gibellula, an araneopathogenic fungus in the Cordycipitaceae family. David Ricardo Díaz-Guevara, an arachnid curator at Ecuador’s National Institute of Biodiversity, travelled from Quito to examine the specimen and confirmed it as a new species through morphological comparison with the seven other members of the genus.
The researchers named the spider Taczanowskia waska and published their description in the journal Zootaxa in February 2026. The species belongs to the family Araneidae, the orb-weavers, though members of the Taczanowskia genus do not build traditional webs. Instead, they rely on enlarged claws on their forelimbs to capture prey.
Why mimic a parasite?
The researchers propose two explanations for the mimicry. The fungal appearance may serve as aggressive camouflage, allowing the spider to ambush prey that mistake it for an infected, immobile host. Alternatively, the tubercles could deter predators such as birds, which avoid consuming fungus-infected arachnids. Cordyceps fungi manipulate host behaviour to disperse spores, a phenomenon that inspired the post-apocalyptic series The Last of Us.
The study notes this is the first reported instance of an arachnid mimicking an araneopathogenic fungus. Previous cases of spider mimicry have involved leaves, bird droppings, and chemical signals, but not the parasites that kill them. The paper also highlights the role of citizen science platforms in biodiversity discovery—several iNaturalist observations from the Napo and Pastaza provinces helped establish the species’ range.
The authors compiled an updated taxonomic key for female Taczanowskia spiders and discussed ecological data collection through community observation networks. The species was found in the Llanganates-Sangay Connectivity Corridor, a biodiverse region spanning multiple protected areas in Ecuador’s eastern Andes and Amazon lowlands.
Source: Zootaxa.
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