Giglioli's Whale: the Two-Finned Whale Seen from the Corvette Magenta

The Magenta was an Italian corvette on a voyage around the globe between 1865 and 1868. Her commander was Frigate Captain Vittorio Arminjon. The voyage's first zoologist, Filippo De Filippi, died in Hong Kong in 1867. Enrico Hillyer Giglioli took over the role.

By the late summer of 1867 the ship had spent a month in Sydney, surveyed Tasmania and failed in an attempt to enter Auckland harbour. Then came the long Pacific leg toward Chile. She would arrive at Valparaíso on 25 September 1867.

4 September 1867. The ship was in the Pacific, about 1,930 kilometres (1,200 miles) off the coast of Chile. Swimming remarkably close to the ship was a whale with two distinct dorsal fins.

The animal was about 60 feet, or 18 metres, long. Its elongated body closely resembled a rorqual, the same family as the blue whale, but with some added features. The two dorsal fins stood about 2 metres apart. One account says they were over six feet high. It had a large pair of sickle-shaped flippers. And its throat was smooth. No pleats. Giglioli watched it for around 15 minutes. He took detailed notes and made drawings.

To Giglioli, the smooth throat and the double fin meant something new. In his 1874 memoir on the cetaceans observed during the voyage, printed in Naples, he gave the animal a name: Amphiptera pacifica. He wrote that the only whale with a dorsal fin and a smooth throat would be "my Amphiptera", and that only one genus would have two dorsal fins.

The name never entered the textbooks. Amphiptera has never been accepted as a valid taxon. No specimen has ever been taken.

The story did not end on the Pacific. In 1868 a fishing boat off Aberdeenshire, Scotland, reported a two-finned whale of roughly the same size. In 1983 the French zoologist Jacques Maigret saw a similar whale between Corsica and the French mainland. A 19th-century report of a "rhinoceros dolphin" with two dorsal fins belongs to the same small family of accounts.

Modern zoologists tend to see a malformed animal. They attribute these sightings to genetic mutations rather than a distinct species. Others argue that commercial whalers would have documented such a distinctive creature had it truly existed. The opposite case came in 1991. In a paper in Aquatic Mammals, "Cetaceans with two dorsal fins", Michel Raynal and Jean-Pierre Sylvestre argued that Amphiptera is a valid entity, has been observed on multiple occasions and may be distinct enough to warrant its own family, the Amphipteridae.

Giglioli went on to direct the Royal Zoological Museum in Florence. His whale lives on in the lists of cryptid whales, beside Trunko and the high-finned sperm whale, and in online catalogues that extend Bernard Heuvelmans' checklist. It rests on a single trained observer, fifteen minutes at sea, and a name that still waits for its proof.