Preliminary report on the geographical distribution of the species of Carinariidae and Pterotracheidae (Heteropoda, Mollusca) from the International Indian Ocean Expedition

Abstract

This is a description of the distribution in the Indian Ocean of species belonging to two families of the Heteropoda, the Carinariidae and Pterotracheidae The observations are based on plankton collected by Anton Brunn, Argo, Pionner and Vityaz during the IIOE The samples obtained by these vessels provide broad coverage of the Indian Ocean, including the Arabian Sea and Bay of Bengal and southward to 40 degrees S Beyond 40 degrees S there were only three collections and these contained no specimens Pterotracheids outnumber the Carinariids in abundance The four species of the genus Carinaria, Cardiapoda richardi, Pterotrachea scutata and Pt minuta deserve special mention because of their low density in the Indian Ocean Most abundant and widely distributed are Firoloida desmaresti and Pterotrachea hippocampus Pterosoma planum and Cardiapoda placenta appear to be more restricted to the tropical zone The identification of the specimens is mainly based upon Tesch (1949)