DNA from two museum specimens of the extinct former North American endemic parrot species have enabled its true relationships to be shown.
Once the only endemic parrot species in North America, Caroline Parakeet once ranged from the tip of Florida north-west to the shores of Lake Ontario, but was extinct by the early 1920s. Its habits, biology and movements were never scientifically studied, and its taxonomic relationships have been assumed from the biometrics of the remaining museum specimens.
Such studies have assumed a close relationship with Monk Parakeet from South America due to both species having a fully feathered cere - the usually feathered area around the bill - and Monk Parakeet appears to be filling its niche in some parts of the USA as an exotic alien.
A team from New York and New Mexico isolated and sequenced two mitochondrial DNA sequences from 43 species of 28 genera of Neotropical parrots including Monk and Carolina parakeets to try and work out the true phylogenetic relationships of New World parrots. The resulting tree demonstrated that the feathered cere condition evolve independently and the two species were only distantly related to each other, with Carolina being most closely related to the South American long-tailed parakeet species of the genera Aratinga and Nandayus. Overall, American parrots appear to have evolved within South America once the ancient continent of Gondwanaland broke up about 110 million years ago. The team's results also suggest that the genus Aratinga does not contain each other's closest relatives and will be in need of revision after further work.
Kirchman, J J, Schirtzinger E E and Wright, T F. 2012. Phylogenetic relationships of the extinct Carolina Parakeet (Conuropsis carolinensis) inferred from DNA sequence data. The Auk 129: 1-8.