PSEUDOSCORPION - Dinocheirus (arizonensis?)
Size: 2.48 mm (male)
Group Guild Status
Eutroglophile Predator Uncommon
Pseudoscorpions are close relatives of scorpions, but are considerably smaller (usually less than 5 mm), and lack the terminal tail with a sting. Pseudoscorpions have their venom apparatus in the tips of their anterior, claw-like pedipalps.
The species is uncommon in the cave, and has been found no deeper into the cave than Grand Central Station, approximately 50 meters from the nearest surface connection. Because we have seen juveniles of the species, we suspect the animals are reproducing in the cave.
We have not observed this species feeding, but likely prey may include the barklouse (P. ramburii) and possibly springtails (collembola), although some springtails are reported to be unpalatable as prey (Fountain and Hopkin 2005). We have seen P. ramburii at all of the locations where the pseudoscorpions were observed, both when the pseudoscorpions were present and at other times.
There is no apparent morphological evidence of cave adaptation in this species, and it is most likely a troglophile in the cave. Interbreeding with an epigean conspecifics may occur. The animals apparently do not occur deep in the cave, and are primarily associated with areas near surface entrances where the humidity is comparatively low (at least seasonally), and where its probable main prey, P. ramburii, also occurs. We found a single juvenile pseudoscorpion, likely this species, in the chelicerae of an adult female spider (Achaearanea canionis) in her web in the Crinoid Room during a post-study visit to the cave on May 31, 2012. The spider was apparently still feeding on the carcass, but there did not appear to be much left of the animal. This pseudoscropion is considered uncommon and localized in the cave.
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