The theory was articulated by University of Otago palaeontologist Prof Ewan Fordyce and Dr Daniel Ksepka, of North Carolina State University, in an article published in the November issue of Scientific American, which has a readership of 0.6 million.
The two researchers say fossil finds in New Zealand since the 1980s suggest penguins developed in Zealandia not long after the end of the dinosaurs 65 million years ago. New Zealand is the largest exposed area of Zealandia, which is a submerged mini continent that broke from the ancient supercontinent Gondwana.
Prof Fordyce told the Otago Daily Times the idea penguins originated in Zealandia was a "developing story", based on the discovery of "protopenguin" fossils, between 58 and 62 million years old, around Waipara.
The fossils, in-between modern penguins and "something like a shag or an albatross", meant here was "as good a guess as any" for the species' origin, so "penguins are ancestral New Zealanders".
Prof Fordyce said Zealandia was a perfect place for penguins to develop: "It was probably almost an island paradise, sitting in the middle of the South Pacific, with rich food resources in the waters around, probably plenty of areas for penguins ... to nest."
Prof Fordyce said it was "nice" having the story published to such a broad audience.