as the Rio Paraguay and Rio Parana, allow for seasonally flooded semievergreen gallery forests that hold riparian species such as Tessaria integrifolia and Salix humboldtiana. Other seasonally flooded ecosystems of this area include palm-dominated (Copernicia alba) savannas with a bunch grass-dominated herbaceous layer. To the west, in the Semiarid/Arid Chaco, medium-sized forests consists of white quebracho (Aspidosperma quebracho-blanco) and red quebracho (Schinopsis lorentzii) with a slightly shorter subcanopy made up of several species from the family Fabaceae, as well as several arboreal cacti species that distinguish this area of the Chaco. There is a scrub-like shrub and herbaceous understory. On sandy soils, the thick woodlands turn into savannas where the aforementioned species prevail, as well as species such as Jacaranda mimosifolia. The giant Stetsonia coryne, found throughout the western Semiarid/Arid region becomes very conspicuous in these sandy savannas. Various upland systems of plant associations occur throughout the Gran Chaco. The Highlands of the Argentinian Chaco are made up of, on the dry, sunny side (up to 1800m), Schinopsis haenkeana woodlands. The cooler side of the uplands hosts Zanthoxylum coco (locally referred to as Fagara coco) and Schinus molleoides (locally referred to as Lithrea molleoides) as the predominant species. Other notable species include Bougainvillea stipitata, and several species from the Fabaceae. The Paraguyan uplands have other woodland slope ecosystems, notably, those dominated by Anadenanthera colubrina on moist slopes. Both of these upland systems, as well as numerous other Gran Chaco areas, are rich with endemism. Fauna Faunal diversity in the Gran Chaco is also high. The Gran Chaco has around 3,400 plant, 500 bird, 150 mammal, and 220 reptile and amphibian species. Animals typically associated with tropical and subtropical forests are often found throughout the eastern Humid Chaco, including jaguars, howler monkeys, peccaries, deer, and tapirs. Edentate species, including anteaters and armadillos, are readily seen here, as well. Being home to at least 10 species, the Argentinian Chaco is the location of the peak diversity for the armadillo, including species such as the nine-banded armadillo (Dasypus novemcinctus), whose range extends north to the southern US, and the southern three-banded armadillo (Tolypeutes matacus). The pink fairy armadillo (Chlamyphrous truncatus), is found nowhere else in the world. The giant armadillo (Priodontes maximus), while not found in the eastern Humid Chaco, can be seen in the drier Arid Chaco of the west. Some other notable endemics of the region include the San Luis tuco-tuco