The Psittaculini could have invaded the area several times, as many of the species were so specialised that they may have evolved significantly on hotspot islands before the Mascarenes emerged from the sea. Other members of the genus "Psittacula" from the Mascarenes include the extant echo parakeet ("Psittacula eques echo") of Mauritius, as well as the extinct Réunion parakeet ("Psittacula eques eques"), and Mascarene grey parakeet ("Psittacula bensoni") of both Mauritius and Réunion. A 2011 genetic study of parrot phylogeny was unable to include Newton's parakeet, as no viable DNA could be extracted. A 2015 genetic study by Jackson et al. included viable DNA from the toe-pad of the female Newton's parakeet specimen. It was found to group within a clade of rose-ringed parakeet subspecies (from Asia and Africa), which it had diverged from 3.82 million years ago. Furthermore, Newton's parakeet appeared to be ancestral to the parakeets of Mauritius and Réunion. The cladogram accompanying the study is shown below:  Newton's parakeet was about long – roughly the size of the rose-ringed parakeet. The wing of the male specimen was , the tail , the culmen , and the tarsus was . The wing of the female specimen was , the tail , the culmen , and the tarsus was . The male specimen was greyish blue (also described as "slatey blue") tinged with green, and darker above. The head was bluer, with a dark line running from the eye to the cere. It had a broad black collar running from the chin to the nape, where it became gradually narrower. The underside of the tail was greyish, the upper beak was dark reddish brown, and the mandible was black. The legs were grey and the iris yellow. The female was similar but had a greyer head and a black beak. The black collar was not so prominent as that of the male and did not extend to the back of the neck. The general appearance of Newton's parakeet was similar to the extant "Psittacula" species, including the black collar, but the bluish grey colouration set it apart from other members of its genus, which are mostly green. The French naturalist Philibert Commerson received a live specimen on Mauritius in the 1770s and described it as "greyish blue".