Gnathifera eurybias is a moth in the family Epermeniidae. It was described by Edward Meyrick in 1897. It is found in Australia, where it has been recorded from New South Wales,[1] Queensland, Victoria, Tasmania and South Australia.
The wingspan is 11–15 mm. The forewings are light fuscous, irregularly strigulated with dark fuscous irroration (sprinkles) and partially finely whitish-sprinkled. There is a black dot beneath the costa near the base, and one in the disc at one-third, as well as an undefined patch of dark fuscous suffusion on the dorsum at one-fourth and a narrow indistinct dark fuscous inwardly oblique median fascia, marked with a small ochreous spot in the disc, and terminating in a large blackish dorsal scale-tooth. There is also a black dot in the disc at three-fourths, followed by a small ochreous spot. The posterior half of the costa is indistinctly spotted with dark fuscous and there is a small ochreous apical spot. The hindwings are fuscous.[2]