The secondary subspecies, C.c.kerguelenensis, is larger than C.c.commersonii, has a less-sharply delineated dark and light grey patterning with a white ventral band, and is found around the Kerguelen Islands in the Indian Ocean.

The dolphin is named after French naturalist Dr Philibert Commerson, who first described them in 1767 after sighting them in the Strait of Magellan.

[4] Two disjunct subspecies of the dolphin are found in geographically disparate areas separated by 130° of longitude and about 8,500 km (5,300 mi); it is not known why they are thus distributed.

[5] The main subspecies, C.c.commersonii, is found inshore in various inlets in Argentina including Puerto Deseado, in the Strait of Magellan and around Tierra del Fuego, and near the Falkland Islands (Las Malvinas).

They reside near the Kerguelen Islands in the southern part of the Indian Ocean, and prefer shallow waters.

[8] The commersonii subspecies has a black head, dorsal fin, and fluke, with a white throat and body.

A mature female caught off of southern Patagonia, at 23 kg (51 lb) and 1.36 m (4.5 ft), may be the smallest adult cetacean on record.

[2] The Commerson's dolphin population of South America is listed in Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals (CMS) because it has an unfavourable conservation status or would benefit significantly from international co-operation organised by tailored agreements.