The Neotropical region consists of South America and Middle America, into which some North American species have moved. South America has the largest freshwater fish fauna in the world, with 32 families of primary freshwater fishes, 4475 valid described species plus at least another 1550 still to be described (Reis et al. 2003). There are no minnows or suckers in South America, but their ecological the text. From Lévêque et al. (2008). equivalents may be in the eight families of characins
with over 1200 species. Other ostariophysans include 13 families of catfishes with about 1300 species, and six families of Gymnotiformes. Cichlids (about 150 species) are the most speciose perciform group. Representatives of many marine families have also invaded South America: freshwater stingrays (Potamotrygoninae), which are en - demic to South America; herrings (Clupeidae); toadfishes (Batrachoididae); needlefishes (Belonidae, three endemic genera and seven species); croakers (Sciaenidae); and soles (Achiridae). Gery (1969) recognized eight faunistic regions but Lévêque et al. (2008) modified this into 10 ichthyofaunal provinces (Fig. 16.9):
1 The South Patagonian Province with12 species (one endemic).
2 The North Patagonian Province with 23 species (five endemic).
3 The Trans-Andean (South) Province with 19 species (13 endemic).
4 The Lake Titicaca Province with 32 species, 30 endemic including the endemic fauna of the cyprinodontoid Orestias.
5 The Paranean Province consisting mainly of the coastal rivers of Argentina plus two large rivers, the La Plata and the Sao Francisco from Brazil, with 847 species (517 endemic).
6 The South-East Brazilian Province with 194 species (90 endemic).
7 The East Brazilian Province, comprising the smaller coastal rivers of eastern Brazil, with 131 species (50 endemic).
8 The Guianean-Amazonian Province, the richest basin, with about 2400 species and more than 2000 endemics.
9 The North Venezuelan Province with 61 species (nine endemic).
10 The Trans-Andean Province, with 423 species (326 endemic).
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