Tooth Cave Pseudoscorpion

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Tooth Cave Pseudoscorpion

Tartarocreagris texana

ListedSeptember 16, 1988
FamilyNeobisiidae (Pseudoscorpion)
DescriptionTiny scorpion-like arachnid.
HabitatCave dwelling.
FoodSmall insects and arthropods.
ReproductionMale deposits sperm on the substratum, which the female picks up for fertilization.
ThreatsDevelopment, exotic predators.


The Tooth Cave pseudoscorpion, Tartarocreagris texana, is a pale yellow to whitish arachnid that resembles a tiny scorpion, reaching about 0.2 in (4 mm) in length. It has the same enlarged pedipalpi terminating in pinching chelae, but the segmented abdomen is broadly rounded behind and lacks a whip or stinger and book lungs. It uses its pinchers to prey on small insects and other arthropods. The unpigmented pseudoscorpion is eyeless; the numerous sensory hairs take the place of eyes.


The Tooth Cave pseudoscorpion preys on small insects and other cave-dwelling arthropods, which it captures with its pinchers and tears into pieces with its strong chelicerae. It is possible that it anesthetizes its victims with venom produced in tiny glands in the chelicerae.

Along with spiders and some mites, this pseudoscorpion produces a kind of silk that comes from the glands that in spiders is used to produce venom. During periods when the species is helpless, such as when the female is distended with eggs or when molting, it spins silk to enclose itself for protection.

To reproduce, the male deposits on the substratum a distinctive spermatophore consisting of a thin stalk whose tip contains a sperm. The female picks it up and fertilizes herself.


This species is found in two dry, relatively small, limestone caves that have some infiltration of groundwater.


The Tooth Cave pseudoscorpion is endemic to Tooth, Amber, and possibly McDonald Caves in Travis and Williamson Counties near Austin, Texas. The pseudoscorpion is not known to exist elsewhere.

The number of Tooth Cave pseudoscorpions in Amber and Tooth Caves has not been estimated, but surveys have only uncovered a single specimen from each cave. Because of the size of the available habitat and the small size of the pseudoscorpion, these survey figures are not thought to indicate actual numbers, although the total population is certainly not large.


Located adjacent to a developing urban area, the caves inhabited by this pseudoscorpion are threatened by land clearing and residential construction. Tooth Cave lies along a proposed route for a water pipeline and, even if bypassed by construction equipment, could suffer from nearby blasting. Residential development of the area will also contribute to the degradation of groundwater.

Conservation and Recovery

Recovery options include acquiring, through purchase or donation, wide easements around caves to protect them from ground disturbance and water pollution. Cave entrances will probably be grated to prevent unauthorized entry and vandalism.

Because the black-capped vireo (Vireo atricapillus ) nests in the region, the U. S. Fish and Wildlife Service (FWS) treated the pseudoscorpion in the vireo's 1991 Recovery Plan, affording additional protection and oversight.


U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
P. O. Box 1306
Albuquerque, New Mexico 87103-1306
Telephone: (505) 248-6911
Fax: (505) 248-6915


Muchmore, W. B. 1969. "New Species and Records of Cavernicolous Pseudoscorpions of the Genus Microcreagris (Arachnida Chelonethida, Neobisiidae, Ideobisiinae)." American Museum Novitate 2932:21.

Reddell, J. R. 1984. "Report on the Caves and CaveFauna of the Parke, Travis County, Texas." Unpublished Report to the Texas System of Natural Laboratories.

U. S. Fish and Wildlife Service. 1988. "Determination of Five Texas Cave Invertebrates to Be Endangered Species." Federal Register 53: 36029-36033.

U. S. Fish and Wildlife Service. 1994. "Recovery Plan for Endangered Karst Invertebrates in Travis and William Counties, Texas." U. S. Fish and Wildlife Service, Albuquerque.