The southeast range extends slightly southwestward into that quadrant, about 1000–1400 km, and its eastern limit is the final 950 km of the Tocantins River drainage.
Its range stays contiguous along the Caribbean coast through the Guianas and only ends south and southeast of the Amazon River outlet with Marajo Island, and the outlet of the downstream Tocantins River, in the northeastern Brazilian state of Maranhão on the Atlantic coast.
In the southeast Basin, it is in the Tapajos River and Xingu River drainages; also two thirds of the adjacent river system, the lower Araguaia–Tocantins River drainage.
The eastern range of Dark-winged Trumpeter extends into the lower adjacent Tocantins River drainage in the Brazilian state of Pará.
The eastern range extends to the upstream third of the Xingu River, then further east to the upstream half of the Araguaia in the Araguaia-Tocantins River system.
In 2014, the population in the Araguaia-Tocantins basin was recognized to be an additional species, Inia araguaiaensis.
It is found in northern Bolivia (Beni Department and Santa Cruz Department) and Brazil (in the southern Amazon between the Tocantins River, Xingu, Tapajós, and Madeira Rivers).
The range of the Ringed Antpipit is the entire Amazon Basin, the Guianan region, Marajó Island, and the southeast Orinoco River Basin region in eastern Venezuela; also the downstream half of the neighboring Amazon Basin river system in the southeast, the Araguaia-Tocantins River, with the range ending easterly on the Atlantic coast of Brazil's Maranhão state.
The rivers in the Amazon Basin, going upstream are the following: Amazon River, (Tocantins, Araguaia— east of the Xingu), Xingu River, Madeira, and Marañón-Ucayali, (in Amazonian Peru).
This corridor is about 700 km wide, and includes the confluence areas downstream of the major rivers: Rio Negro, Madeira, Tapajós, Xingu, and the outlet section of the Tocantins River in the southeast Basin's neighbouring river system, Araguaia-Tocantins.
The Spotted Tody-Flycatcher is a bird of the Amazon Basin and in the east the neighboring Araguaia River of the Araguaia-Tocantins River drainage.
To the east-southeast, the range encompasses the Amazon's adjacent Tocantins-Araguaia River drainage as well as about 900 km eastward.
Two other tributaries, called the Maranhão and Paranatinga, collect an immense volume of water from the highlands which surround them, especially on the south and south-east.
East of the Tapajós, the range expands into the Cerrado, the upper half of the Xingu River drainage, and the entire drainage system of the Araguaia-Tocantins River, (the eastward system, typically considered part of the 'Amazon Basin').
The White-tailed Cotinga's southeast Amazon Basin range encompasses the lower drainage, (about one third), of the Tocantins-Araguaia River system, and ends in the east at the Atlantic Ocean in the state of Maranhão.
The range of the Yellow-browed Tody-Flycatcher is mainly in the southern Amazon Basin, and in the east limited by the Amazon River; in the southeast, its range extends eastward including Ilha de Marajo and the last downstream region of only the Tocantins River, of the Araguaia-Tocantins River system.
Yellow-crowned Elaenia is found in the Amazon Basin along the major river course of the Amazon, also the outlet of the adjacent Tocantins River, then after an interruption in the range along the Amazon River, it is along Amazon drainages from eastern Peru, and Ecuador along the river corridors.
Mississippi River | River Thames | Amazon River | Columbia River | Hudson River | Colorado River | Potomac River | river | Ohio River | Missouri River | Delaware River | Murray River | River Tyne | Madeira River | Volga River | River Nene | River Clyde | River Trent | River Severn | Amur River | River Wear | Allegheny River | Red River | Dnieper River | Yarra River | Paraná River | River Tees | Fraser River | Yangtze River | Tocantins River |
Other limits to Dusky Parrot's range is northwest Maranhão state Brazil, Baia de Sao Marcos; also in the southeast Amazon Basin, the confluence of the northern flowing Araguaia-Tocantins River.
Potamobatrachus trispinosus is a species of toadfish endemic to Brazil where it is found in the Araguaia and Tocantins Rivers.
Besides the Amazon Basin it is found in the southeast basin in the adjoining Tocantins-Araguaia River drainage; on the east at the edge of its range there, it only occurs in the headwaters of the Tocantins, then recontinues at the joining of the Araguaia-Tocantins as it goes to the Atlantic Ocean.