On the identity ofProdelphinus petersiiLütken, 1889 and records of dusky dolphinLagenorhynchus obscurus(Gray, 1828) from the southern Indian and Atlantic oceans

Abstract

Prodelphinus petersii Lutken. 1889 from Amsterdam Island is assigned as a junior synonym of the dusky dolphin Lagenorhynchus obscurus (Gray. 1828). This identification and three confirmed sightings from near the Prince Edward Islands represent the first records of the dusky dolphin from the Indian Ocean. L. obscurus is documented also for the first time from the mid-Atlantic near Gough Island, and its much disputed occurrence off the Falklands Islands is confirmed. Possible sightings of L. obscurus from both the southern Indian and Atlantic oceans are reviewed. Available evidence Supports a disjunct distribution for L. obscurus and the existence of discrete stocks confined to continental shelves and oceanic island groups. However, the taxonomic status of Lagenorhynchus species sighted in offshore tropical waters needs to be clarified.