The spectacled porpoise was briefly placed into its own genus and listed as Australophocaena dioptrica. Recent genetic studies however have resulted in it being placed back in the genus Phocoena. Very little is known about this species as to date, there have only been a few dozen confirmed sightings at sea.
One of the larger members of the porpoise family, the spectacled porpoise is stocky and almost beakless. The flippers are close to the small head and have rounded tips while the flukes are distinctly notched with pointed tips. One of the most distinctive characteristics of this species is the dorsal fin. In males, it is large and rounded with a large base, while that of females is smaller and more triangular. Colouration is two-tone with the back being blue-black and strikingly contrasting to the bright white belly and lower flanks. It has black lips and dark gape to flipper stripes, and white rings around its eyes which give the spectacled porpoise its name. The flippers vary from dark grey to white. There is a white band on top of the tailstock and the dorsal side of the flukes may also be white in some individuals. The spectacled porpoise may be confused with Commerson's dolphins, as well as the Burmeister's porpoise. Colouration however is markedly different and the dorsal fin of the spectacled porpoise is very distinctive. Like all porpoises, their teeth are 'spade-shaped' (dolphins' teeth are conical). On their upper jaw they have up to 52 teeth, and on their lower jaw they have up to 42.
Not much is known about the behaviour of the spectacled porpoise. They are inconspicuous, fast swimmers, generally avoid boats and, as with other members of the genus Phocoena, are not thought to be highly acrobatic. In the few documented sightings, spectacled porpoises have been observed in groups of between 1 and 5 individuals.
Spectacled porpoises have been seen most often around the southeastern coast of South America, but their range may extend in a circumpolar band around the southern hemisphere as they have also been reported in oceanic waters, off the coast of Tasmania, and around a variety of offshore islands. Spectacled porpoises are known to be taken intentionally off of Southern Chile for use as crab bait, and like other porpoises they are incidentally caught in gill and trawl nets. No global estimate exists for this species, and the IUCN lists this species as ‘Data Deficient'.