This is a highly specialized fossorial squamate reptile characterized by a cylindrical, limbless body that is evolutionarily adapted to an underground existence. It displays a dorsal coloration ranging from yellowish-brown to pale greyish-brown, transitioning to a lighter, often pinkish underside. Its skin is divided into regular rings or annuli that facilitate telescopic movement through the soil, featuring 190 to 215 body annuli and 18 to 24 tail annuli. The head is robust, heavily ossified, and wedge-shaped, serving as a primary burrowing organ. Its eyes are rudimentary, tiny, and covered by a protective translucent scale, restricting its vision to basic light detection. The snout-vent length typically ranges between 200 and 320 millimeters, with a slender body mass that optimizes underground navigation. The tail is short, blunt, and morphologically resembles the head, serving as an effective anti-predator decoy mechanism.

Geographical distribution: This species is widely distributed throughout the temperate and subtropical regions of South America. Its geographic range encompasses southern Brazil (specifically the states of Rio Grande do Sul and Santa Catarina), the entirety of Uruguay, and the northeastern and central-eastern provinces of Argentina, including Buenos Aires, Entre Ríos, Santa Fe, and Córdoba.

Habitat: It is primarily found in grasslands, shrubby savannas, and open woodlands, showing a strong affinity for the Pampean and Espinal biomes. It requires loose, sandy, or loamy soils with adequate moisture levels that facilitate easy burrowing. Individuals are frequently uncovered beneath deeply embedded rocks, decaying logs, or inside active ant and termite nests, where microclimatic conditions remain highly stable.

Feeding: It maintains a strictly carnivorous and opportunistic diet, preying upon various subterranean invertebrates. Its prey includes beetle larvae, earthworms, spiders, centipedes, and subterranean termites. To locate food in complete darkness, it relies on its highly developed chemosensory system (Jacobson’s organ) and extreme sensitivity to low-frequency soil vibrations, securing prey with robust jaws lined with sharp, recurved teeth.

Behavior: It exhibits strictly subterranean (fossorial) habits, rarely venturing above ground except when heavy rains flood its tunnels or during agricultural tilling. Its underground locomotion is rectilinear or accordion-like, relying on the independent movement of its ringed skin envelope over its musculature. When threatened, it displays a defensive self-mimicry strategy known as the two-headed posture, raising both its head and rigid tail simultaneously to disorient predators; it can also deliver a painful, defensive bite.

Reproduction: The reproductive strategy of this species is oviparous. Females deposit a small clutch of 2 to 5 elongated, flexible-shelled eggs during late spring or early summer. These eggs are buried deep in the soil, under large stones, or frequently placed inside active leaf-cutter ant nests of the genera Acromyrmex or Atta, which provide optimal, stable temperature and humidity levels. Incubation lasts several weeks, yielding fully independent hatchlings.

Conservation status: It is currently assessed as Least Concern (LC) on global and regional red lists due to its extensive geographical distribution and adaptable nature. However, localized populations face threats from habitat fragmentation driven by intensive agriculture, the widespread use of chemical pesticides that deplete its food source, and direct persecution from humans who mistake it for a venomous snake.