The Great Basin Cave Pseudoscorpion, USA Cave Animal of the Year 2020

First published in The Midden*, Great Basin National Park's newsletter, Vol. 20, No. 1, Summer 2020. By cave biologists Gretchen Baker, Michael Slay and Matthew Niemiller.*

Cave Animal of the Year is an international programme that draws attention to the animals living underground. Germany began it in 2009; Italy and Australia joined in 2019, and the United States in 2020.

The first U.S. choice

The USA's 2020 Cave Animal of the Year was the Great Basin cave pseudoscorpion (Microcreagris grandis Muchmore), a small arachnid in the family Neobisiidae. Its genus, Microcreagris, has more than 20 related species, found around the world in caves and above ground.

How it was found. In the 1930s, T. O. Thatcher, custodian (roughly today's superintendent) of what was then Lehman Caves National Monument, noticed and collected the first specimens. They were not identified until the 1960s, when Dr. William Muchmore recognised a new species and named it. It has since turned up in other caves in the park, alpine caves among them — but not in caves in any other mountain range.

What a pseudoscorpion is

• Relatives. Pseudoscorpions are distant relatives of spiders, scorpions, harvestmen and mites. They look like scorpions but have no stinging tail — hence the name "false scorpion".
• Size. Most species are very small: up to three-tenths of an inch (8 mm).
• Body. Eight legs, and large claw-like pedipalps for grabbing prey.
• Diet. Insects of many kinds — flies, beetles, larvae and tiny springtails.
• Diversity. There are more than 3,500 species worldwide.

Small as they are to us, they are giants in the cave ecosystem: pseudoscorpions are the top invertebrate predator in the park's caves. Young ones (protonymphs) are paler than adults.

Sources

• National Park Service, Great Basin National Park, "USA Cave Animal of the Year," The Midden, Vol. 20, No. 1, Summer 2020. https://www.nps.gov/articles/000/usa-cave-animal-of-the-year.htm
• Cave Animal of the Year programmes: Germany, https://hoehlentier.de/en/ · Italy, https://animalidigrotta.speleo.it/ · Australia, https://www.caveanimaloftheyear.org.au/
• The original's photograph of a young pseudoscorpion is credited to a named photographer, not the NPS, and is not reproduced here.
• Words on this page from people and organisations outside the federal government are paraphrased; rewritten in hubnx's own words.