Wikipedia
The genus Nelepsittacus consists of four extinct parrot species and is closely related to the genus Nestor. All recovered from early Miocene Saint Bathans Fauna from the Lower Bannockburn Formation in Otago in New Zealand, three of the four species have been named. Features in their skeletons, namely the coracoid, humerus, tibiotarsus, and tarsometatarsus, that they share only with the Nestor parrots link them to that genus.
The genus is named for the Greek mythological figure Neleus who was the father of Nestor, reflecting the relationship between the genus and the extant Nestor. The type species is N. minimus, the smallest of the species so far recovered. Nelepsittacus donmertoni is the next-smallest species, and its bones indicate it was about the same size as the crimson rosella (Platycercus elegans) of eastern Australia. It was named in honour of the late Don Merton, who was instrumental in saving the Kakapo. Bigger still is the next species, N. daphneleeae, about a quarter larger again than N. donmertoni. The humerus and ulna of this parrot suggest it was a little bigger than the Australian king parrot (Alisterus scapularis) but a little smaller than a galah (Eolophus roseicapillus). The last species, so far undescribed and known only from a left scapula and humerus, is around the same size as a kea (Nestor notabilis).
Flora from the Saint Bathans fauna fossil beds indicate these parrots were found in a subtropical rainforest habitat. Following the early to mid Miocene, there was a drop in temperature, which led to a loss of local flora and fauna.