Phylum Chordata Bateson, 1885 - chordates
   Subphylum Vertebrata Cuvier, 1812 - vertebrates
     Pisces
       Class Actinopterygii Woodward, 1891 - ray-finned fishes
         Order Osteoglossiformes Berg, 1940 - bonytongues
           Family Gymnarchidae Bleeker, 1859
           Family Hiodontidae Cuvier & Valenciennes, 1846 - mooneyes
           Family †Lycopteridae
           Family Mormyridae Bonaparte, 1831 - elephantfishes
           Family Notopteridae Bleeker, 1851 - knifefishes
           Family Osteoglossidae Bonaparte, 1845 - bonytongues and arapaimas
           Family Pantodontidae Peters, 1876
           Family †Singididae see Family Osteoglossidae Bonaparte, 1845
           Family †Wakinoichthiidae Yabumoto, 1994