As some of the biggest arachnids in the world, bird-eating spiders are many people's idea of a living nightmare. Well, for those with arachnophobia out there, this may not be welcome news as researchers have just described three new species of bird-eating spiders, one of which has a penchant for climbing trees.

The researchers didn’t have to travel to the depths of the rainforest to scout out new spiders, though. All they had to do was go through museum records and collections. In what may appear to many as a bit paradoxical, the researchers found that there were not 49 species of bird-eating spiders in the Avicularia genus as had been thought, but only 12. Three of these are new to science, with one belonging in its own unique genus.

It was Carl Linnaeus, famed for coming up with the system by which we name species, who first described the Avicularia genus in 1758. “He described the species based on a hodgepodge of spiders,” explain the authors in their paper published in ZooKeys. “Over the next centuries, other species with completely different characteristics were called Avicularia, creating a huge mess.”

A juvenile Ybyrapora diversipes. Rogério Bertani

It was in a bid to clean up this mess of taxonomy that the three new species lurking in the collections were discovered. This is by no means the first time that new species have been found sitting in a drawer. In 2013, scientists discovered an entirely new species of mammal, the olinguito, hidden in the collection of Chicago’s Field Museum.

One of the new species of spider has been named Avicularia merianae, after the late 17th-century scientist Maria Sibylla Merian (1647-1717). The little-known German-born naturalist is famous for her illustrations, and is credited with being one of the first to make direct observations of insects and their lifecycles, documenting how caterpillars turn into chrysalises before metamorphosing into butterflies.

The original illustration by Merian showing a spider eating a bird. Maria Sibylla Merian/Wikimedia Commons

But she also self-funded an expedition to Suriname, at the time a rare endeavor for a woman. While there, she documented the native plants, insects, and reptiles, noting their habitat, behavior, and uses to indigenous peoples. More importantly, however, it is thought that one of these illustrations of a tarantula feasting on a hummingbird is what gave rise to the name that would then become commonplace to describe arachnids belonging to Avicularia: bird-eating spiders.

The researchers describe two other species, including one that now resides in its own genus Ybyrapora. The mouthful of a new genus is derived from the local indigenous language Tupi, and translates as “those that live in trees”, which relates to its habit of climbing in the Brazilian Atlantic rainforest.