Neonothopanus nambi is a poisonous and bioluminescent mushroom in the family Marasmiaceae. Italian-Argentinian naturalist Carlos Luigi Spegazzini described the species in 1883 as Agaricus nambi in the subgenus Pleurotus, from material collected in December 1879 near Guarapi in Brazil. Pier Andrea Saccardo placed it in the genus Pleurotus.Ronald H. Petersen and Irmgard Krisai placed the fungus in the new genus Neonothopanus in 1999.