Characterized by a subquadrate and moderately convex carapace, this decapod crustacean exhibits a highly granulated dorsal surface adorned with faint transverse ridges. It possesses three distinct anterolateral teeth on each side of the carapace, excluding the outer orbital angle. The chelipeds are robust and heavy, being significantly larger and more inflated in adult males than in females, showcasing a coloration that ranges from greenish-grey to dark brown, often mottled with yellowish patterns that provide excellent camouflage. Adult males typically achieve a carapace width of 35 to 50 millimeters, making them highly conspicuous members of their benthic communities. The walking legs are slightly flattened and fringed with setae along the margins, which assists them in navigating muddy, sandy, and rocky substrates.

Geographical distribution: This species is widely distributed along the southwestern coast of the Atlantic Ocean. Its range extends from southern Brazil (including records from Rio de Janeiro and Rio Grande do Sul), spanning the entire coastline of Uruguay, and stretching down to the cold temperate waters of Argentine Patagonia, reaching as far south as the Santa Cruz Province and the San Jorge Gulf. This extensive range highlights its high physiological tolerance to varying latitudinal temperatures and environmental gradients.

Habitat: Primarily found in intertidal and shallow subtidal zones, it displays a strong preference for estuarine systems, coastal lagoons, Spartina salt marshes, and muddy-sand flats. It is an extremely euryhaline organism, capable of withstanding severe fluctuations in salinity, ranging from oligohaline river mouths to hypersaline lagoons. It also seeks refuge under rocks, crevices, and consolidated debris on mixed shores where currents are moderate.

Feeding: Functioning as an opportunistic omnivore, this decapod plays a crucial trophic role in coastal food webs. Its diet is remarkably broad, consisting of organic detritus, benthic microalgae, macroalgae, and various invertebrates such as polychaetes, small bivalves, gastropods, and smaller crustaceans. By feeding on both primary producers and small metazoans, it acts as a major energy conduit to higher trophic levels, including predatory fish and migratory shorebirds.

Behavior: It exhibits intensive burrowing activity, creating intricate networks of tunnels and burrows in soft sediments. This bioturbation behavior significantly modifies the physical and chemical properties of the mud, enhancing sediment oxygenation and nutrient cycling. Highly active during both diurnal and nocturnal cycles, its movements are tightly synchronized with tidal fluctuations. Males display highly territorial and agonistic behaviors, employing their enlarged chelipeds for visual displays and physical combat to defend resources and secure mating opportunities.

Reproduction: The reproductive cycle is highly seasonal, peaking during the warmer months of spring and summer. Sexual dimorphism is pronounced, with males possessing a narrow, T-shaped abdomen, while females feature a broad, rounded abdomen designed to carry the egg mass. Following copulation, the female deposits and carries the fertilized eggs attached to her pleopods under her abdomen until hatching. The larvae are released into the water column, undergoing several pelagic zoeal stages and a megalopa stage before settling back onto the substrate to metamorphose into benthic juveniles.

Conservation status: It is not currently listed under any threat category on the IUCN Red List and is generally regarded as a species of least concern locally due to its high density and ecological resilience. However, populations residing near major urban and industrial centers face localized threats from coastal pollution, habitat degradation, port construction, and microplastic contamination, emphasizing the need for ongoing habitat monitoring.