The first known physical remain of the broad-billed parrot was a subfossil mandible collected along with the first batch of dodo bones found in the Mare aux Songes swamp. The British biologist Richard Owen described the mandible in 1866 and identified it as belonging to a large parrot species, to which he gave the binomial name "Psittacus mauritianus". This holotype specimen is now lost. The common name "broad-billed parrot" was first used by Owen in a 1866 lecture. In 1868, shortly after the 1601 journal of the Dutch East India Company ship "Gelderland" had been rediscovered, the German ornithologist Hermann Schlegel examined an unlabelled pen-and-ink sketch in it. Realising that the drawing, which is attributed to the Dutch artist Joris Joostensz Laerle, depicted the parrot described by Owen, Schlegel made the connection with the old journal descriptions. Because its bones and crest are significantly different from those of "Psittacus" species, the British zoologist Alfred Newton assigned it to its own genus in 1875, which he called "Lophopsittacus". "Lophos" is the Ancient Greek word for crest, referring here to the bird's frontal crest, and "psittakos" means parrot.