Belongs to a highly adapted family of primary freshwater decapod crustaceans, characterized by a subquadrate to slightly subcircular carapace that is remarkably flattened dorsally, with its anterolateral margins displaying three to five sharp teeth. The overall coloration of the exoskeleton ranges from olive brown to grayish brown, frequently blending into yellowish tones that offer superb camouflage within muddy riverbeds. Marked sexual dimorphism is evident in adult specimens; males possess highly asymmetrical chelipeds, with one major claw being significantly larger and more robust for defense and mating displays, whereas females exhibit a much broader abdomen designed for holding offspring. The carapace width of fully grown individuals typically measures between 30 and 45 millimeters, supported by relatively long walking legs bordered with dense setae that enhance stability and movement on soft, slippery muddy substrates.

Geographical distribution: Occurs endemically within the extensive Paraná River and Paraguay River basins, encompassing vast wetland territories across Argentina, Paraguay, southwestern Brazil, and extreme eastern Bolivia. It is exceptionally abundant in the alluvial plains near Colastiné in the Santa Fe province of Argentina, which inspired its scientific species name, as well as throughout the complex marshes of the Paraná Delta.

Habitat: Prefers slow-moving or stagnant freshwater systems, including marginal lagoons, temporary wetlands, drainage ditches, and seasonally flooded alluvial plains connected to major river systems. It is strictly associated with muddy, clayey, or silty bottoms that accumulate abundant organic detritus, as well as areas dense with floating or rooted aquatic vegetation, which provide crucial protection against visual predators and rich foraging grounds.

Feeding: Exhibits opportunistic omnivorous and scavenging feeding habits, functioning primarily as an active detritivore within its ecosystem. Its diet is largely composed of decaying organic matter, aquatic macrophyte tissues, filamentous algae, and small benthic invertebrates, such as oligochaetes, aquatic insect larvae, microcrustaceans, and small freshwater snails, which are carefully processed using its specialized mouthparts.

Behavior: Displays a predominantly nocturnal and crepuscular activity pattern, remaining concealed during daylight hours beneath submerged logs, rocks, or buried within deep burrows excavated in the soft mud of riverbanks. It possesses a remarkable tolerance to dehydration, enabling individuals to travel across terrestrial terrain during periods of high atmospheric humidity to locate new water bodies or escape severe hypoxia in drying pools.

Reproduction: Characterized by direct development, an evolutionary specialization of freshwater crabs that bypasses the free-swimming planktonic larval stages typical of marine decapod species. Mating takes place during the warmer months, after which the female carries the fertilized eggs securely attached to her pleopods beneath her folded abdomen; upon hatching, the juveniles emerge as miniature versions of the adults and remain sheltered under the maternal abdomen for several weeks before dispersing.

Conservation status: Classified globally as Least Concern or sometimes categorized as Data Deficient in localized regional red lists due to the scarcity of comprehensive long-term population monitoring. Nevertheless, local populations face growing threats from water pollution caused by agricultural runoff and industrial effluents, habitat fragmentation due to drainage projects, and the modification of natural hydrological cycles within its native river basins.