Spectacled Porpoise

The Spectacled Porpoise (Phocoena dioptrica) is a rarely seen member of the porpoise family. The species is readily distinguished from other porpoises by a characteristic dark ringaround the eyes, which gives the animals their name. This ring is commonly surrounded by a farther lighter ring.

Taxonomy

The Spectacled Porpoise was first described by Lahille in 1912 from a specimen found on a beach near Buenos Aires . A skull later found in Tierra del Fuego was initially thought to be another species, provisionally named Phocoenadioptrica but the individual was later shown to be a spectacled porpoise and this name remains a synonym. The Latin worddioptrica refers to the double eye rings characterizing the creature.

Physical description

The Spectacled Porpoise is a robust creature with a small head and no beak. Males have a large dorsal fin. Individuals aredark grey to black on the dorsal fin with a very distinct line to a white to light grey ventral side. Newborn members of thisspecies are about 80 cm with males growing up to 2.2 m and females somewhat smaller. The age at which they reach maturity, aswell as a porpoise's longevity, is unknown. The Spectacled Porpoise is a fast swimmer.

Distribution and population

The Spectacled Porpoise is believed to be circumpolar in cool sub-Antarctic and low Antarctic waters. Many skeletons have beenfound on Tierra del Fuego and this area is believed to be a site of relatively high concentration. This species has been seen off Brazil , the FalklandIslands and South Georgia in the Atlantic, off Auckland , Tasmania and south Australia in the South Pacific and Heard Island and Kerguelen in the southern Indian Ocean . Individuals havevery rarely been seen in the open sea. The southernmost sighting was in the Drake Passage at 58° S.

The total population is unknown. The IUCN lists it as a data deficient species in theRed List of Threatened Species.

External links

• Spectacled Porpoise factsheet page from phocoena.org contains an image of thespecies