Scorpions in the Sky – New Species Discovered on Madrean Discovery Expedition


Charles T. Vorhies was a zoologist at the University of Arizona from 1910 through the 1920s. He was a naturalist who explored the Sky Islands of southeastern Arizona. In 1940, Herbert Ludwig Stahnke, the scorpion specialist at Arizona State University, described a new species of scorpion from the Huachuca Mountains Vaejovis vorhiesi in his honor. It turns out that similar but different scorpions reside in many Sky Island mountain ranges in Arizona and Sonora. This is a very interesting example of natural selection for new species on isolated mountaintops.

Stahnke’s student, Oscar Franke described V. pelonsilloensis from the Peloncillo Mountains on the Arizona-New Mexico border as part of his PhD studies at ASU. Oscar is now the Curator of the Mexican National Arachnid Collection at the National University in Mexico City. He supports’s Madrean Discovery Expeditions (MDE) program with use of his collecting permit and identifications of scorpions found on Expeditions. In 2013, Tom Van Devender and John Palting discovered scorpions in the Sierra la Mariquita near Cananea and just south of the Arizona Border. These tiny reddish scorpions were hunting in pine needles on a cold rainy night – lowland scorpions hunt on dry, warm nights.

One of Oscar’s graduate students, Diego Barrales found more of them on MDE Sierra Elenita in 2016. Just this year, Diego, Oscar, and Tom described them as Vaejovis islaserrano – another Sky Island endemic in the V. vorhiesi-group. Isla Serrana is Spanish for Sky Island. On a recent scouting trip to MDE Mesa Tres Ríos (in the northern Sierra Madre Occidental), Tom, Nora Villanueva, and Arehli Ballesteros found tiny scorpions in their El Respresito camp. These looked similar to the la Mariquita animals, except they were nearly black. Dr. Francke just examined the specimens and reports that they are another new species! And that the V. vorhiesi-group will split and the new species will be in the new genus!


Madrean Discovery Expeditions is dedicated to exploring, studying, and protecting the Madrean Archipelago, a series of unique ecosystems that range from New Mexico and Arizona to Mexico.