Hemicordulia armstrongi (Rowe 2019) is a very recent addition to the catalogue. The common name above is that currently used in New Zealand, though both H. armstrongi and H. australiae may co-exist there and are most probably being referred to by the same name. I am not yet aware of a distinct common name being attached to H. armstrongi in Australia.
Specimens of H. armstrongi have been, until recently, considered to be H. australiae (Australian Emerald) but closer examination has noted significant physical differences between both the larvae and the adults of these two species. There are also said to be noticeable differences in the male mating behaviour. These differences, discussed in Rowe’s 2019 paper, led to the recognition of H. armstrongi and there are now two sibling species which may overlap both in Australia and New Zealand.
We observed the specimen below at Cape Foulwind in South Island, New Zealand in 2017. My original research prior to our New Zealand 2017 trip had suggested that the species, then just H. australiae, was limited to North Island but that information was either out of date or just plain incorrect.
Our individual kept flying constantly and was ill illuminated by very harsh back-lighting. Thus, the shots that we managed are not the greatest. It seems clear, though, particularly in the first picture, that this specimen matches the description of H. armstrongi, especially in regard to S8-S10 being black with no yellow.