Paravaejovis spinigerus

Distinguished from the Arizona bark scorpion (Centruroides sculpturatus) by: (1) brownish-tan stripes on the dorsal keels of the tail versus unstriped tail in bark scorpions; (2) thicker tail relative to the pedipalps versus slender tail and pedipalps in bark scorpions; (3) more robust overall build. The striped tail pattern is diagnostic for field identification in its range.

Medium-sized scorpion with adult males and females reaching 60–70 mm in body length and approximately 9.5 g in weight. Body base color ranges from light yellow to golden brown with variable darker markings. The metasoma (tail) displays distinctive brownish-tan stripes running along the dorsal keels or ridges—this striping is the source of both the common name and the specific epithet. The tail is thicker than the pedipalps (claws), which are relatively slender. The species name spinigerus refers to the spiniform granules present at the ends of the dorsal keels of the tail. Some individuals exhibit dusky underlying markings along the tail.

Occurs in the Sonoran Desert from desert floor to rocky hillsides. Found under rocks and surface objects including sleeping bags and shoes. Also occurs on sandy soils. Actively seeks the most humid microhabitats available within its arid environment.

Native to the southwestern United States (Arizona, New Mexico, and parts of California) and northwestern Mexico (Sonora, Baja California, and Baja California Sur).

Feeds on small invertebrates including other scorpions, crickets, mealworms, and cockroaches.

Gestation lasts 3–8 months. Females give birth to live young (scorplings), with litter sizes ranging from 1 to 100 individuals. Birth may occur as single offspring emerging at intervals or as a continuous flow. Females exhibit a distinctive rigid, inflexible posture during late gestation, with front legs lowered to allow offspring emergence. Mothers carry young on their backs until the first molt. Some females may cannibalize offspring; the factors determining maternal care versus cannibalism are unknown.

Nocturnal. Males and females engage in a courtship dance lasting from minutes to hours prior to mating; if the male persists longer than the female desires, the female may attack and consume him. Females use smell and vibrations to locate mates. Seeks humid microhabitats within arid environments.

Predator of small invertebrates. Prey for pallid bats, sand-swimmer snakes, spiders, centipedes, lizards, birds, mammals, and other scorpions.

Commonly encountered by humans in its range due to habit of sheltering under rocks, sleeping bags, and shoes. Venom is not medically significant and the species is not considered dangerous to humans or other mammals. Frequently misidentified as more dangerous scorpion species.

• Centruroides sculpturatus (Arizona bark scorpion)Sympatric in Arizona; distinguished by slender tail and pedipalps, lack of dorsal tail striping, and medically significant venom.

Often feared due to confusion with the Arizona bark scorpion (Centruroides sculpturatus), which has medically significant venom. The stripe-tailed scorpion's venom is not dangerous to humans, though stings may cause local pain.

• scorpion
• arachnid
• desert
• venomous
• nocturnal
• viviparous
• maternal care

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