A female of the new species and genus of tarantula Kankuamo marquezi
Photograph by Dirk Weinmann
Tarantula lovers know to avoid the bristles that cover their favorite giant arachnids. Getting a face full of these stinging bristles can be deadly for small mammals, and in humans they create an annoying itch.
But recently, a closer look at the irksome barbs proved fortunate for arachnologists from universities in Uruguay and Colombia. The team noticed that the rust-colored barbs on a tarantula found near Colombia’s Caribbean coast formed a pattern that looked nothing like the hairs found on other tarantulas.
Males of these particular spiders also have strange genitalia covered with serrated ridges, leading the scientists to realize that the animal belongs to a completely new genus and species, as they describe today in the journal ZooKeys.
The team named the new tarantula Kankuamo marquezi, in part after Colombian literary great and team favorite Gabriel García Márquez, author of One Hundred Years of Solitude and Love in the Time of Cholera.
Unique Weapon
The large size of tarantulas may make it hard to believe that many species remain undiscovered by scientists.
“There are currently around a thousand known species of tarantula, but there’s probably at least as many that haven’t been described,” says Gustavo Hormiga, a spider expert at George Washington University. “If we keep discovering new species at the same rate we have been for the last few centuries, it will take us years and years and years to describe everything.”
However, the massive arachnids camouflage themselves well in the rain forests and scrublands where they live. They also spend an inordinate amount of time in underground burrows, only coming out to hunt at night.
“It’s easy to see how a species could stay unknown for so long,” says study co-author Fernando Perez Miles of the University of the Republic in Uruguay.
The researchers found the new tarantula on an expedition to catalog spider biodiversity in the Sierra Nevada de Santa Maria region of Colombia. They noticed that the brown-black tarantula is covered in rust-colored bristles, including an unusual oval patch of sharp-tipped barbs.
What stood out to them the most was the way the spider used its bristles. Most tarantulas face their potential enemies while rubbing their hind legs over their abdomens. Then, they aim and shoot a group of these bristles at their target. Tiny barbs on these hairs point in the opposite direction from the tip of the bristle, to help the hairs stay embedded after being fired.
In the new tarantula, however, the barbs point in the same direction as the bristle tip. What’s more, the spider doesn’t launch the bristles at their enemies, instead embedding them directly into any animals that dared to touch its body.
It’s the first species known to use these so-called urticating hairs in a direct attack, says Perez Miles. His colleague Carlos Perafán also learned the hard way that the itch factor on these bristles is just as significant as it is in other species.
The unique strategy could be used to defend the spider against a specific type of predator or to attack a certain type of prey.
Strange Serration
For the researchers, the odd bristles alone pointed to not just a new species of tarantula, but a new genus. Their hunch was confirmed when they inspected the spider’s genitals. Male spiders don’t have a penis, but instead have palpal bulbs at the ends of their front legs that transfer sperm to females.
The palpal bulbs are often covered in rough skin called keels. In this new tarantula, the keels formed a completely unique pattern and were covered with serrated edges that made the organ look like a scraper or güiro, a musical instrument with ridges that makes noise when rubbed with a stick.
In addition to honoring the Nobel prize-winning author García Márquez, the researchers named the new tarantula genus after the Kankuamo, the indigenous people of this Caribbean region, whose language and culture is severely endangered.
“Mid-level predators like tarantulas often have huge effects on an ecosystem. That’s why each new discovery is so important,” says Jo-Anne Nina Sewlal, an arachnologist at the University of the West Indies on the island of Trinidad.
“Tarantulas get a really bad rap, but they are really valuable to our ecosystems,” Sewlal adds.
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