In 1973, based on remains collected by the French amateur naturalist Louis Etienne Thirioux in the early 20th century, the British ornithologist Daniel T. Holyoak placed a small subfossil Mauritian parrot in the same genus as the broad-billed parrot and named it "Lophopsittacus bensoni". In 2007, on the basis of a comparison of subfossils, correlated with 17th and 18th century descriptions of small grey parrots, Hume reclassified it as a species in the genus "Psittacula" and called it Thirioux's grey parrot. In 1967, the American ornithologist James Greenway had speculated that reports of grey Mauritian parrots referred to the broad-billed parrot.