We describe a new and unusual species of funnel-web spider from the far south coast of New South Wales. Hadronyche nadgee sp. nov. has only a single row of cheliceral teeth, a condition unique among known atracids. All Atrax, Illawarra, and Hadronyche species described to date have teeth on both sides of the cheliceral groove. Moreover, a retromarginal row of large teeth has been one of the diagnostic features of the Atracidae. Hadronyche nadgee sp. nov. has only a promarginal row. We therefore amend the diagnosis of the family to accommodate this new species, which in all other ways meets the criteria for Hadronyche (Atracidae).