How many butterfly species occur in New Zealand? (Don't pretend you don't care, you know this matters...) My Butterflies of New Zealand (1970) lists a mere 17, and this seems to be the core species quotient, but figures vary - happily in an upward direction - and Wikipedia lists 26. Very much larger numbers of New Zealand moths have been identified, but lepidopterists agree that there are probably at least 200 more moth species yet to be described. What's more, the list of butterflies might eventually add up to something like 70 (more than the UK), including 25 new species of Copper - the research has yet to be done.
The fact is that, across all of Nature and all of the world - even Britain - new species are being discovered all the time. This story from India illustrates one of the ways in which this happens. Estimates of the number of species on the planet vary so widely that it's safe to conclude that no one really has any idea, except that it's very, very big. Even today, there are great swathes of the most aboundingly biodiverse parts of the world where nobody has seriously looked. And the other side of the story is that species previously thought extinct also keep popping up again, alive alive oh. Here - also from India - is the latest. There is no real certainty about either the number of species or how many of them are extinct. The world is always infinitely more complex and much less known than we think.