Will climate change drive newly discovered tarantula species to extinction?

A new species of tarantula, Aphonopelma jacobii, has been discovered in the Chiricahua Mountains of southeastern Arizona. This small, black and gray tarantula species has fiery red hairs on its abdomen and can be found in high-elevation habitats in the Chiricahua Mountains, where it survives extremely cold winters.

The discovery was rather unexpected. “We often hear about new species being discovered in remote corners of the Earth, but it’s remarkable that these spiders are in our own backyard, even if they are somewhat difficult to access,” said Dr. Chris Hamilton, an assistant professor at the University of Idaho and co-senior author of a study in ZooKeys Keys who is reporting on the spider.

“With Earth in the midst of a human-induced extinction crisis, it’s astonishing how little we know about our planet’s biodiversity, even about remarkable and charismatic groups like tarantulas.”

The Chiricahuas, renowned for their exceptional biodiversity and high levels of endemism, are part of the Madrean Archipelago (colloquially called the Madrean Sky Islands), a complex of forested mountain ranges that span the Cordillera between the Colorado Plateau and the Rocky Mountains in the southwestern United States and the Sierra Madre Occidental in northwestern Mexico.

These “islands” of mountain forests, separated from each other by lowland deserts and arid grasslands, evolved in isolation, leading to the origin of many short-range endemic species and resulting in a mosaic of biodiversity unlike any other region in the United States.

The forests where these tarantulas live are threatened by several factors, including climate change. Recent studies in the Sky Islands region suggest that these forests will be “pushed” away from the mountains in the coming decades as temperatures and precipitation continue to rise and fall, respectively. Organisms adapted to these cooler, wetter mountaintops, such as these spiders, will likely disappear as suitable habitat disappears.

Dr. Brent Hendrixson, a professor at Millsaps College and co-senior author of the study, added: “These fragile habitats are also threatened by increasing urban development in the San Simon Valley and Portal areas, destructive recreational activities, and wildfires. In addition, there is concern that these tarantulas are being exploited for the exotic pet trade due to their rarity, striking coloration, and docile nature. We must consider the impact that unscrupulous collectors may have on these spiders when determining the threats to this species and the implications for its conservation.”

Aphonopelma jacobii is named after Michael A. Jacobi, who helped find several of the early specimens that led to the description of this new species.

“This discovery represents the 30th tarantula species recorded in the United States. Aphonopelma is the most species-diverse tarantula genus on the planet (at least for recorded species). Our research adds to that number and continues to advance our understanding of the true species diversity in this incredibly interesting and important biodiversity hotspot,” concludes Dr. Hamilton.