A mysterious pheasant, the Double-banded Argus, Argusianus bipunctatus, is known only from the portion of a single primary flight feather. It was described in 1871 from this feather piece, found in a millinery shipment imported to London.

Its origin was hypothesized to be from Java, Indonesia or Tioman Island of Malaysia, because of the Great Argus' absence from these locations. Parkes (1992) vehemently rejected the "species" validity and argued that the Double-banded Argus almost certainly represents a mutant form of the Great Argus. The IUCN, following the precautionary principle, lists this taxon as extinct.

While the feather is indeed quite distinct, it represents a fairly simple divergence: The entirely asymmetrically-pattern vanes are instead near-symmetrical and both bear the darker brown shaftward area with innumerable whitish speckles. The shaft is thinner than usual and the feather would probably not have been useful for flight.

Nothing similar has come to notice ever since, and as the feather piece is not a composite of two feather halves glued together but a natural (albeit peculiar) specimen, a hoax or fake can be ruled out. Nonetheless all conjecture that has been built around the feather piece, all that can be said is that at some time around 1870 an argus pheasant was shot in an unknown location which bore at least one such feather. Even if this one known individual was the last remnant of a disappearing population, it is hard to believe that only a single feather would have been taken from an unusual specimen of a well-known, often-hunted, and conspicuous bird, and that this single feather would have been then transported elsewhere, to be bundled into a shipment of perfectly normal Great Argus feathers.

The feather is now housed in the British Natural History Museum. A photo of the specimen is in Fuller (2000:111).

See also

• Bogotá Sunangel
• Hooded Seedeater