The specific epithet honours Dr John Grant-Mackie, Associate Professor of Geology at Auckland University, in recognition of his support for graduate students and for contributions to avian palaeontology.

The specific epithet honours Dr John Yaldwyn, Director of the National Museum of New Zealand in Wellington, in recognition of his contributions to avian palaeontology.

[1] Either flightless or nearly so, it became extinct following the occupation of New Zealand by the Polynesian ancestors of the Māori, and the associated introduction of the kiore (Pacific rat).

Since it has been found in association with four other species of acanthisittids in four genera (at the Honeycomb Hill Cave site) it is likely that its ecological niche was different enough for it to have coexisted with them.

Sites where it was found indicate that it inhabited lowland mixed podocarp broadleaf forest, ranging upwards into alpine tundra scrubland.