“…However, proxy signals preserved in foraminiferal shells have been shown to vary significantly between species (Erez, 1978;Hemleben et al, 1989;Spero, 1998;Spero et al, 2003), with species identifications being strongly reliant on morphological concepts (Tendal, 1990). As a result of these interspecies differences, which are generally attributed to vital effects or ecological factors such as depth habitat and/or seasonal preferences, species-specific proxy calibrations are necessary in order to produce the most reliable estimates of past ocean conditions (Hemleben et al, 1989;Spero et al, 1997;Bijma et al, 1998;Bemis et al, 2002). Despite attempts to differentiate between morphologically defined species, the paleoceanographic community has long recognized the existence of morphotypes within species of planktonic foraminifera, often finding a large range in morphologies within a single population (Kennett, 1976;Deuser et al, 1981;Bé et al, 1983;Deuser, 1987;Deuser and Ross, 1989).…”