Relationship of Indian Ocean Epiplanktonic Calanoids to the World Oceans

Abstract

Circumglobal distributions are widely accepted as commonplace among epiplanktonic species of Zooplankton and especially for those copepods occurring in warm oceanic waters (Sewell, 1948). Nevertheless, the warm-water belt lying roughly between latitudes 40° N and 40° S is not a continuous circle. Interruptions include a virtually perfect warm-water barrier, the Americas, separating the Atlantic and Pacific Oceans, the extensive Afro-European barrier separating the Atlantic from the Indian Ocean as far south as latitude 35° S and the mosaic of land masses and shallow seas comprising the Austral-Asian boundary intervening between the Indian and Pacific Oceans. These barriers appear a priori to be formidable deterrents to panmixis and in all likelihood they have prevailed in their relative positions at least since the end of the Tertiary (Darlington, 1965).