Revised 28 Feb. 2023
PDF version (with illustrations and additional infor-mation)

Arapaima Müller 1843 presumably derived from warapaima, local (Carib language) name for species of the genus among the Macushi indigenous people of southern Guyana, northern Brazil and eastern Venezuela [predates Sudis arapaima Valenciennes 1847 and therefore is not tautonymous with it]

Arapaima agassizi (Valenciennes 1847) in honor of Swiss (later American) zoologist-geologist Louis Agassiz (1807–1873), whose 1829 text and osteological illustrations of the Pirarucú were the basis for Valenciennes’ description

Arapaima arapaima (Valenciennes 1847) as for genus [treated as a junior synonym of A. gigas by some workers]

Arapaima gigas (Schinz 1822) gígas (Gr. γίγας), giant, the largest freshwater fish in the Amazon (up to 4.5 m and 200 kg)

Arapaima leptosoma Stewart 2013 leptós (Gr. λεπτός), thin or slender; sṓma (Gr. σῶμα), body, referring to its relatively slender body form compared with A. arapaima

Arapaima mapae (Valenciennes 1847) of Lago Mapa (now Lago do Amapá), Amapá State, Brazil, type locality

Heterotis Rüppell 1829 héteros (Gr. ἕτερος), different; ōtós (Gr. ὠτός), genitive of oū́s (οὖς), ear, referring to helically shaped suprabranchial organ on fourth gill arch [incorrectly dated by some sources to Rüppell’s 1828 Atlas zu der Reise im nördlichen Africa]

Heterotis niloticus (Cuvier 1829) –icus (L.), belonging to: Nile River, type locality