| Summary: | Analyses of the size, porosity and shape of 366 specimens of Botryostrobus auritus/australis retrieved from 17 surface sediment samples distributed more or less evenly between the equator and 64° S in the western Pacific Ocean show that most shape-related features vary rather evenly from the tropics to the pole, suggesting a close relationship with surface temperature and/or salinity; the size and porosity of the shells, on the other hand, are more closely associated with primary productivity in the upper layers than with latitude. Most changes are smooth and stepwise, although for several characters there is an increase in the average rate of variation in the southernmost tropical to northern subantarctic areas, in coincidence with the zone of the species' maximum relative abundance. It is concluded that the morphologic differences studied are not consistent enough as to justify the division of B. auritus/australis into several distributionally more restricted taxa. On the other hand, the overlap for the ranges of most traits in the various climatic zones transected is of such magnitude that it restricts the potential usefulness of the shape, porosity and size patterns surveyed as ecologic or paleoecologic indicators. © 1989. Fil:Boltovskoy, D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Vrba, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
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