Giglioli’s Whale (Amphiptera pacifica) is a purported species of whale observed by Enrico Hillyer Giglioli. It is described to have two dorsal fins, a feature which no known whales have.
On September 4, 1867 on board a ship called the Magenta about 1200 miles off the coast of Chile, the zoologist spotted a species of whale which he could not recognize. It was very close to the ship (too close to shoot with a cannon.) and was observed for a quarter of an hour, allowing Giglioli to make very detailed observations. The whale looked overall similar to a rorqual, 60 feet (18 m) long with an elongated body, but the most notable difference was the presence of two large dorsal fins about 6.5 feet (2 m) apart. No known whales have twin dorsal fins; the rorqual only has a single fin and some other whales have none. Other unusual features include the presence of two long sickle-shaped flippers and a lack of furrows present under the throats of rorquals.
Another report of a two finned whale of roughly the same size was recorded from the ship Lily off the coast of Scotland the following year. In 1983 between Corsica and the French mainland, French zoologist Jacques Maigret sighted a similar looking creature.
Some humpback whales have been seen to be with two dorsal fins due to either being deformed or wounded.
Although it has not been proven to exist, it was given a "classification" by Giglioli. However, scientists would probably classify the whale under Balaenopteridae, large baleen whales.
The whale may have been a genetic mutation. Another cryptid with two dorsal fins is the fabled Rhinoceros Dolphin.
Given the species' alleged size (60 feet) and attributes (it resembles a rorqual), it is extremely doubtful such a species would not have been taken (and reported) by modern commercial whalers, bringing into doubt its very existence. However, many new species of whale have been discovered in recent years, many of them just from carcasses.