G. giganteus may refer to: Geosaurus giganteus, an extinct marine crocodyliform reptile species from Western Europe of the Late Jurassic Gigantopithecus giganteus, an extinct large ape species that lived in what is now India Gymnopilus giganteus, a mushroom species Synonyms Gastrochilus giganteus, a synonym for Rhynchostylis gigantea, an orchid species