Terrifying New Spider With Toxic, Skin-Rotting Bite That Likes to Lurk in Clothing Discovered in Mexico

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From the archives: This story was last updated in January 2020.

Scientists have unearthed a brand-new species of venomous spider in central Mexico with a penchant for hiding in household furniture and fabrics. Perhaps most unsettling of all, the spider has a bite so potent that it can rot human flesh.

If the penny-sized arachnid were to bite a human, a sore would develop, quickly turning purple. If left untreated, necrotic lesions up to 40 centimeters in width could spread around the site of the puncture wound.

Not a pretty sight.

“The critical stage is the first 24 hours,” professor Alejandro Valdez-Mondragon told The Yucatan Times, “and sometimes up to 48 hours when you begin to see the effects.” Wounds may take several months to heal and can leave permanent scarring. The venom is particularly dangerous for children.

However, there is good news for arachnophobes; the spider is not thought to be lethal, and there does exist an effective, though pricey, medical antidote.

The arachnid was named Loxosceles tenochtitlan by professor Valdez-Mondragon and his biological research team from the National Autonomous University of Mexico (UNAM)—comprising Claudia Navarro, Karen Solis, Mayra Cortez, and Alma Juarez, as per the UNAM Gaceta.

The spider was first reported by news media in December 2019 after having been found in the city of Tlaxcala in central Mexico. It is the 139th species in the “recluse” or “violinist” family of venomous spiders. Researchers initially mistook the arachnid for a related recluse species Loxosceles misteca, ordinarily found in Morelos and Guerrero.

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“As it is very similar to the L. misteca we thought that it had been introduced to this region by the shipping of ornamental plants,” Valdez-Mondragon explained, as per the UNAM Gaceta, “but when doing molecular biology studies of both species, we realized that they are completely different.”

Loxosceles tenochtitlan is native to the Valley of Mexico region and is one of 40 recluse species native to Mexico as a whole.

What makes this new venomous species distinct from its cousins, said Valdez-Mondragon, is its shorter leg length, the shape of the male tibia, and the female reproductive structure.

In addition, while the spider’s main color is a muted dark brown, unlike other Loxosceles spiders, tenochtitlan has a particularly visible violin-shaped dorsal pattern, exemplifying the family nickname: “violinist.”

According to the Daily Mail, the male of the species hunts for females—thought to be twice as toxic as males—to mate with on balmy evenings during bouts of wet weather. On their surreptitious hunt, males frequently end up in small crevices, between bed sheets, in the folds of clothing, or inside shoes.

The preferred habitats of the Loxosceles species in Mexico are dry and tropical forests, Valdez-Mondragon explained, per ZooKeys, including deciduous forests, and deserts.

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Additionally, the professor continued, some species have even been found dwelling in caves, a “preferred microhabitat.” While the spider is not actively aggressive, it has been known to bite human flesh as a defensive mechanism if threatened.

Our homes are also a favorable environment. “We provide them with the temperature, humidity, and food to establish themselves,” Valdez-Mondragon explained, “which puts us at risk of having an accident with them, although they also perform an important ecological function when feeding on insects.”

The downside to the species’ helpful insect-ingesting habit, however, is that Loxosceles tenochtitlan may be attracted to a home if trash is left for long enough to accumulate insect activity. The best way to deter these spiders, say the experts, is to keep homes as clean and tidy as possible.

In Mexico, it might just save a trip to the emergency room.