Belongs to a robust lineage of the Lycosidae family, characterized by its impressive size, with adult females reaching a body length of 20 to 30 millimeters, while males are slightly smaller. The cephalothorax features a dark brown base split by a lighter longitudinal median band, while the abdomen or opisthosoma displays a distinctive arrowhead-shaped or dark chevron pattern on its dorsal surface. However, the most definitive diagnostic feature of this taxon is the coloration of its chelicerae, which are densely covered in vibrant, bright reddish-orange or scarlet hairs. It possesses eight eyes arranged in three distinct rows, with the posterior median eyes being highly developed to grant outstanding visual acuity. Its powerful legs, adapted for cursorial pursuit, are marked with alternating dark and light bands.
Geographical distribution: Occurs extensively throughout the eastern plains and temperate zones of southern South America. Its geographic range covers vast territories in central and southern Brazil, particularly in states like São Paulo and Rio Grande do Sul, as well as the entirety of Uruguay, broad regions of Paraguay, and the central and northern territories of Argentina, extending down to the Pampean grasslands and northern Patagonia.
Habitat: Shows a strong preference for open and semi-open ecosystems, establishing thriving populations in native grasslands, shrubby steppes, forest edges, and savanna biomes. Due to its remarkable ecological plasticity, this arachnid frequently colonizes human-altered landscapes, becoming highly abundant in suburban gardens, agricultural fields, vacant lots, and urban parks, where it seeks shelter beneath rocks, fallen logs, or crevice systems in the soil.
Feeding: Functions as a highly active, cursorial, generalist predator that does not construct webs to capture its prey. Its diet consists primarily of a wide range of terrestrial arthropods, such as crickets, cockroaches, beetles, and various insect larvae, and it may occasionally practice cannibalism or hunt smaller arachnids. To secure its meals, it relies on its remarkable physical speed and sharp binocular vision, stalking prey along the ground before delivering a rapid strike and subduing it with a venomous bite from its powerful jaws.
Behavior: Exhibits primarily nocturnal and crepuscular activity patterns, spending the daylight hours hidden away under leaf litter, stones, or inside shallow burrows lined with silk. It is a strictly solitary and territorial organism known for its rapid locomotion. When threatened, it performs a highly visual defensive display, rearing up on its hind legs while elevating its anterior limbs to expose the bright red warning coloration of its chelicerae. Although its venom can cause mild localized pain and swelling in humans, it is not considered aggressive toward people, choosing flight over conflict whenever possible.
Reproduction: The mating cycle begins with a complex courtship ritual in which the smaller male produces species-specific vibrations by drumming his pedipalps and abdomen against the ground, a behavior critical to appeasing the larger female and preventing sexual cannibalism. Following successful copulation, the female constructs a durable, spherical silk egg sac that she carries securely attached to her spinnerets. Upon hatching, the spiderlings climb onto their mother´s dorsum, densely covering her abdomen. She carries and defends them for several weeks until they undergo their first post-embryonic molt and disperse into the surrounding environment via ballooning.
Conservation status: Has not been formally evaluated on the global Red List of the International Union for Conservation of Nature (IUCN). However, given its widespread geographic distribution, high population density, and remarkable tolerance for human-impacted landscapes, the species is locally regarded as of least concern, facing no imminent threats of extinction.
Compilation and publication: EcoRegistros – 23/07/2026