Notes on South American Dolphins of the Genera Inia, Sotalia and Tursiops. American Society of mammalogists. Vol. 44, No. 1 pp. 98-103. Venezuela, Rio Orinoco, Lake Maracaibo.

Project Details

Date : 1963
Volunteer Name : Hershkovitz, P.

Project Description

Abstract: Presence of the river dolphin Inia geoffrensis Blainville in the Rio Orinoco system is documented for the first time. Sotalia guianensis Van Beneden, known from the Guianan coast, is now shown to range westward into the Lake Maracaibobasin in Venezuela. The Rio Orinoco Sotalia seen by Alexander von Humboldt may be annectant between S. guianensis and the Amazonian S. fluviatilis Gervais and Deville. Present data indicate that the cataracts of the Orinoco and of some Guianan and upper Amazonian streams are not barriers to the distribution of dolphins across the divides during periods of inundation. A skull of bottlenosed dolphin from the Galapagos and another from Talara, Peru, agree with Tursiops nuuanu Andrews of the north Pacific, T. gephyreus Lahille of the southeastern Pacific and T. catalania Gray of the southwestern Pacific. Absolute separation of these forms from T. nesarnack of the northeastern Atlantic does not appear to be indicated. The Pacific bottlenosed dolphin is, therefore, provisionally treated as a subspecies, Tursiops nesarnack catalania Gray. Tursiops gilli Dall of the California coast appears to be distinct.