Question: What direction does the river that Austrolebias bellotti are found in flow?

Context paragraphs:
Cruces River: The Cruces River (Spanish: "Río Cruces" ) is a river near Valdivia, Chile.  Río Cruces originates from hills near the Villarica volcano and flows then in south-west direction.  The southern and final part of the river follows the Valdivian Coastal Range.  At the latitude of Valdivia it is crossed by Río Cruces Bridge near its outflow into Valdivia River.  The small village of Punucapa is the main centre for tourism in Río Cruces.  The river flow through (or near) the cities of Loncoche, Lanco, and Mariquina.  Some of the wetlands in the river's lower flow are inside Carlos Anwandter Nature Sanctuary, a protected area that in the river that extends roughly from Punucapa in the south to San Luis de Alba Fort in the north.

Mouth bar: A mouth bar is a bar in a river that is typically created in the middle of a channel in a river delta.  It is created by a positive feedback between mid-channel deposition and flow divergence.  As the flow diverges near the ocean, sediment settles out in the channel and creates an incipient mouth bar.  As flow is routed around the incipient bar, additional sediment is deposited on the incipient bar.  This continued process results in the formation of a full-fledged mouth bar, which causes the channel to bifurcate.  This continued process leads to the characteristic fractal tree pattern found in some prograding river-dominated deltas.

Antidune: An antidune is a bedform found in fluvial and other channeled environments.  Antidunes occur in supercritical flow, meaning that the Froude number is greater than 1.0 or the flow velocity exceeds the wave velocity; this is also known as upper flow regime.  In antidunes, sediment is deposited on the upstream (stoss) side and eroded from the downstream (lee) side, opposite lower flow regime bedforms.  As a result, antidunes migrate in an upstream direction, counter to the current flow.  Antidunes are called in-phase bedforms, meaning that the water surface elevation mimics the bed elevation; this is due to the supercritical flow regime.  Antidune bedforms evolve rapidly, growing in amplitude as they migrate upstream.  The resultant wave at the water's surface also increases in amplitude.  When that wave becomes unstable, breaks and washes downstream, much of the antidune bedform may be destroyed.

Austrolebias bellottii: Austrolebias bellottii is a species of fish that lives in the basins of the Paraná River and Uruguay River, in Argentina and Uruguay.

Uruguay River: The Uruguay River (Spanish: Río Uruguay , ] ; Portuguese: Rio Uruguai , ] ) is a river in South America.  It flows from north to south and forms parts of the boundaries of Brazil, Argentina, and Uruguay, separating some of the Argentine provinces of La Mesopotamia from the other two countries.  It passes between the states of Santa Catarina and Rio Grande do Sul in Brazil; forms the eastern border of the provinces of Misiones, Corrientes, and Entre Ríos in Argentina; and makes up the western borders of the departments of Artigas, Salto, Paysandú, Río Negro, Soriano, and Colonia in Uruguay.

Meander cutoff: A meander cutoff occurs when a meander bend in a river is breached by a channel that connects the two closest parts of the bend.  This causes the flow to abandon the meander and to continue downstream.  Cutoffs are a natural part of the evolution of a meandering river.  Rivers form meandering bends or meanders as they flow laterally downstream.  Meandering rivers flow the fastest on the outside bend of a river where the river erodes the surrounding landscape.  On the inside bend of a river, water flows slower and sediment builds up creating point bars. Rivers are commonly described and interpreted by their sinuosity.  Sinuosity is the ability of a river to curve or meander throughout its entire length.  It is calculated from the ratio of the distance between points along a river by the straight distance between those points.  Meandering rivers have a sinuosity value of greater than 1.5.  A sinuosity value of less than 1.1 is a “straight” river.  Between the values of 1.1 and 1.5, a river is described as sinuous which describes rivers that are in a transitory state between a “straight” river and a meandering river.  Braided rivers do not follow this same convention.  Meandering rivers trend in the direction of increasing sinuosity.

Foreset bed: A foreset bed is one of the main parts of a river delta.  It is the inclined part of a delta that is found at the end of the stream channel as the delta sediment is deposited along the arcuate delta front.  As the sediments are deposited on a sloping surface the resulting bedding is not horizontal, but dips in the direction of current flow toward deeper water.  A cross-section of a delta shows the cross bedding in the direction of stream flow into the still water.

Livenza: The Livenza (Latin: "Liquentia" , Friulian: "Livence" , Venetian: "Łivensa" ) is a river in the Italian provinces of Pordenone, Treviso and Venice.  Its source is near Polcenigo and Caneva in Pordenone.  It flows in a southeasterly direction past Sacile and forms the border between the provinces of Pordenone and Treviso roughly between Brugnera and Motta di Livenza.  It continues to flow in a southeasterly direction, forming the border between the provinces of Treviso and Venice before flowing into the province of Venice near Santo Stino di Livenza.  It flow near La Salute di Livenza and finally enters the Adriatic Sea near Caorle.

Big Lost River: The Big Lost River is a major river in the U.S. state of Idaho, about 135 mi long.  It starts in the Rocky Mountains and flows in a generally southeast direction into the Snake River Plain.  True to its name, the Big Lost River's surface flow does not reach any larger river, but vanishes into the Snake River Aquifer at the Big Lost River Sinks, giving the river its name.  The river is one of the Lost streams of Idaho, several streams that flow into the plain and disappear into the ground.

Laurentian Divide: The Laurentian Divide or Northern Divide is a continental divide in North America dividing the direction of water flow in eastern and southern Canada from that of the northern Midwestern United States.  The Laurentian Divide separates the river systems that flow northwards to the Arctic Ocean and Hudson Bay from those that flow southwards to the Atlantic Ocean, Caribbean Sea and Gulf of Mexico.  The Laurentian Divide runs from its junction with the primary Continental Divide at Triple Divide Peak in Glacier National Park in Montana, and terminates at Cape Chidley on the Labrador Sea.

Supporting paragraphs: Austrolebias bellottii Uruguay River
Answer: north to south