Taxonomy & naming
Potamotrygon boesemani was formally described by Rosa, Carvalho and Almeida Wanderley in 2008 and is placed in the family Potamotrygonidae, order Myliobatiformes — the stingrays. The family Potamotrygonidae is a natural group of South American freshwater rays, and Potamotrygon is its largest and most species-rich genus. These are elasmobranchs: their skeleton is of cartilage, not bone, making them close relatives of the sharks and the marine rays rather than of any of the bony fishes that otherwise populate this atlas.
The species was named in honour of Dr. Marinus Boeseman (1916–2006), the Dutch ichthyologist whose decades of work on Surinamese freshwater fish laid much of the foundation for the country's ichthyological literature. The epithet carries that legacy. In the ornamental trade the fish circulates under the names Boeseman's stingray and red-lattice stingray, the latter referencing the vivid ocellated patterning. The Catalog of Fishes (Eschmeyer, California Academy of Sciences) is the authority for the valid name.
Morphology
Potamotrygon boesemani has the form characteristic of its genus: a rounded, nearly circular pectoral disc flattened for a benthic life, with the eyes and paired spiracles on the dorsal surface and the mouth, nostrils and five pairs of gill slits on the ventral surface. The spiracles — the paired openings just behind and lateral to the eyes — are the inhalation route for respiration, allowing the ray to breathe while buried in sediment. The disc reaches a maximum recorded width of approximately 16–17 in (males slightly smaller than females on average), and the tail, armed near its base with a serrated venomous spine, adds considerable length beyond that.
The dorsal disc is dark brown, patterned with deep orange to red ocellated spots arranged in irregular concentric series — a particularly intense colouration compared with the otherwise similar P. motoro, P. henlei and P. leopoldi, and a key feature in its original diagnosis. The tail lacks ocelli. The skin is covered with minute tooth-like denticles (not true scales) and is sensory-rich on the underside, where the pores of the ampullae of Lorenzini form a dense field used to detect the faint bioelectric fields of buried prey.
Males are identified by their paired claspers — rod-like copulatory organs formed from the inner margins of the pelvic fins, used to transfer sperm during internal fertilisation. The tooth formula records 45 rows in the upper jaw. Vertebral counts run 119–129.
Habitat
Potamotrygon boesemani is a narrow endemic, known only from the Corantijn River drainage in Suriname. The Corantijn (internationally also spelled Courantyne or Corentyne) is a medium-sized Guiana Shield river forming the border between Suriname and Guyana, draining an upland forested catchment before widening across a coastal plain. Its waters are broadly characteristic of Guiana Shield drainages: warm, relatively soft, and near-neutral to mildly acidic, coloured from dissolved organic material.
Like all of its genus, P. boesemani is a benthic fish of sandy and fine-sediment substrates in the riverine environment. It lies partly buried — sometimes with only eyes and spiracles exposed — in the quieter margins, sandy beaches and shallows of the river system. This burrowing behaviour serves both concealment from predators and ambush feeding. The restricted range of the species means it is wholly dependent on the health of this single drainage.
Feeding
Potamotrygon boesemani is a carnivore and a bottom hunter, as is characteristic of the genus. It detects prey — aquatic insect larvae, crustaceans, worms and small fishes — primarily through the ampullae of Lorenzini, which can sense the minute electrical fields generated by living animals buried in or moving through sediment. The disc is used to pin prey against the substrate, from where it is worked to the jaw and crushed by the closely packed tooth rows.
In the aquarium it accepts the rich meaty diet typical of Potamotrygon: earthworms, prawns, mussel meat, pieces of fish and high-quality prepared foods offered on or near the substrate. Like all large river stingrays it is a substantial feeder and its waste load is correspondingly high, placing additional demands on the filtration system.
Mating
Fertilisation in Potamotrygon boesemani, as in the whole of the order Myliobatiformes, is internal. A male approaches a receptive female and grips her disc margin with his mouth — bite marks on the disc rim are a common sign of courtship — then introduces one of his paired claspers to transfer sperm. Courtship can be vigorous and extended, and the claspers are visible in mature males as paired, rod-like structures projecting from the inner margins of the pelvic fins.
No external eggs are released; the entire early phase of development is internal to the female from the moment of fertilisation. Given the species' restricted range and the pressures on its habitat and population, the opportunity for captive-bred reproduction makes any successful mating event significant for the long-term viability of ex-situ populations.
Breeding
Potamotrygon boesemani is viviparous, giving birth to fully formed live young, and uses the sophisticated nourishment system found throughout the family: after the small egg yolk is exhausted, the developing pups are sustained in the uterus by a protein- and fat-rich secretion — a uterine milk (histotroph) — produced by the uterine wall and taken up directly by the embryos. This matrotrophic histotrophy, documented across Potamotrygon in dedicated reproductive studies, allows pups to grow substantially before birth.
A female carries a small litter — typically a handful of pups, the exact litter size reflecting the limited data available for this recently described species — through a gestation of several months, and delivers miniature, independent rays. There is no parental care after birth; the pups are self-sufficient from the outset. The consequence of this reproductive biology — small litters, a long gestation, and the late maturity typical of elasmobranchs — is a very low intrinsic rate of population increase, which is central to understanding why even modest harvesting pressure is damaging for range-restricted species like this one.
In the aquarium
Potamotrygon boesemani is an advanced-keeper species that is occasionally available in the ornamental trade, more often as wild-caught animals than captive-bred stock. Any serious intent to keep it should begin with sourcing a captive-bred specimen; the species' Vulnerable status and restricted range make additional wild collection pressure difficult to justify.
The physical requirements mirror those of the genus: an aquarium measured in square metres of floor area (width and length far more important than height), with a deep bed of soft, fine sand for burrowing — sharp substrates abrade the thin, scaleless disc. The water must be warm (around 77–82 °F), soft, and near-neutral to mildly acidic, maintained with powerful biological filtration and large, frequent water changes. River stingrays produce copious waste and are exquisitely sensitive to ammonia and nitrate accumulation; there is no margin for neglect. No salt, no copper-based medications, and no aggressive or fin-nipping tankmates.
The serrated venomous tail spine is a genuine medical hazard — a stingray wound is intensely painful and can require hospital treatment — making this species entirely unsuitable for households with young children and subject to legal restrictions or licensing requirements in many jurisdictions. The long lifespan, large adult size and high maintenance costs make this a multi-year commitment requiring serious preparation.
Conservation
The IUCN Red List assessed Potamotrygon boesemani as Vulnerable (VU) in February 2025, under criteria A2cde and B1ab(iii), reflecting a combination of suspected population decline and the acute risk that attaches to any species confined to a single river drainage. Being a single-drainage endemic means that any significant deterioration of the Corantijn watershed — habitat degradation, water quality change, or sustained harvest — threatens the entire global population of the species.
Identified pressures include collection for the ornamental trade, habitat degradation within the drainage, and the general threats facing Guiana Shield rivers from gold-mining activity (mercury contamination) and land-use change. The species is not currently listed in CITES Appendix III, which means it does not benefit from international trade-monitoring controls that apply to some other Potamotrygon. The Important Shark and Ray Areas (ISRA) programme has designated the Courantyne River as an ISRA specifically because of the presence of this range-restricted, threatened species.
The slow reproductive biology of the species — small litters, a multi-month gestation, and the late maturity inherent to elasmobranchs — means that P. boesemani populations recover slowly from depletion. Keeping of captive-bred rather than wild-caught individuals, continued monitoring of the Corantijn population, and formal consideration of CITES listing or export controls are the conservation priorities most directly relevant to the ornamental trade.