It has been assumed that the Antarctic has never been colonized by the higher fly species — the Diptera or "true" flies. In a Brief Communication in the May 8 Nature, Allan C. Ashworth and F. Christian Thompson from North Dakota State University in Fargo describe a fossilized pupa that shows classical dipteran morphology and is derived from rock deposited during the Neogene epoch (3–17 million years ago) (Nature, 423:135-136, May 8, 2003).

Ashworth and Thompson extracted the fossil from a Neogene siltstone outcrop at the Beardmore Glacier, approximately 500 km from the South Pole. Using scanning electron microscopy, they estimated the fossil length to be 5 to 7.5 mm and discovered that it bore structures consistent with it being a cyclorapphan dipteran. These structures include a single pair of round spiracles, an integument with circular patterning (reflecting the chitin secretion pattern), spines on the ventral welt,...