Carnaby's black cockatoo and Baudin's black cockatoo were once known collectively as the white-tailed black cockatoo ("Z. baudinii") until formally classified as separate species. In a 1933 report on the birds of Lake Grace, Western Australian naturalist Ivan Carnaby wrote of a distinctive population of white-tailed black cockatoos that he named mallee black cockatoos. These birds lived in mallee and sandplains, using their large bills to crack open woody seed pods; the typical form had a long narrow bill it used to extract eucalypt seeds from marri's seed pods. He classified it as a subspecies of the white-tailed black cockatoo in 1948, giving it the name "Calyptorhynchus baudinii latirostris". The epithet "latirostris" is from the Latin "latus" "wide" and "rostrum" "bill". The holotype specimen is from Hopetoun, Western Australia.