Overview
Merton’s parrot, Nelepsittacus donmertoni, is known from fossils found near Saint Bathans in Otago that are approximately 20 million years old. The naming of the parrot acknowledges the renowned conservationist Don Merton.
Two other Nelepsittacus parrots are known from the same fossil deposits. Among living parrots, these fossil species are closest to the kākā and kea. The kākāpō is in the same superfamily of parrots, Strigopoidea, which is only found in New Zealand. The Nelepsittacus fossils indicate that the kākā/kea and kākāpō lineages had already diverged by about 20 million years ago.
These Saint Bathans’ fossils were deposited at the side of a large lake. Plant fossils indicate the vegetation was a mosaic of diverse subtropical rainforest and dry woodland. Besides many birds, the area was also home to crocodiles and turtles.
The high diversity and endemism of animals and plants in this fossil record suggests that some of the ancestral New Zealand landmass remained above sea during the so-called “Oligocene drowning event” around 23 million years ago. This was when the land that became New Zealand was reduced to its smallest size. Some have hypothesised that it was even completely submerged. However, if that had been the case, it would be surprising that so much diversity unique to ancestral New Zealand had evolved by approximately 20 million years ago.
Fossils of Nelepsittacus parrots in Te Papa’s Collections Online.
Specimens of kākāpō , kākā, and kea in in Te Papa’s Collections Online.
References:
Miskelly CM (2013) Merton’s parrot. In Miskelly CM (ed.). New Zealand Birds Online.
Worthy TH, Tennyson AJD, Scofield RP (2011) An Early Miocene diversity of parrots (Aves, Strigopidae, Nestorinae) from New Zealand. Journal of Vertebrate Paleontology 31: 1102-1116. Online abstract.