Modern kennel club classification A number of modern kennel clubs, including the Fédération Cynologique Internationale, group the distinct mastiffs with livestock guardian dogs as a single type they call "molossoid". It has been theorised that this confusion is due to mistranslations of ancient texts and assumptions based solely on size. See also List of dog breeds List of extinct dog breeds Molossus of Epirus References Extinct dog breeds Dog breeds originating in Europe