Summary: | Statistical analysis of a literature-based compilation of phylogenetic relationships and biometric measurements of 136 Neogene planktonic foramhiferal species yielded well defined relationships between latitude and morphology. It was found that keel development is a significant factor in latitudinal diversification. The trend of keel development in individual speciation events tends to accompany resmiction in latitude range. This restriction trend also applies to development of the keel within a lineage, with the opposite trend, keel loss, leading to increased latitudinal species range. Mile investigating the temporal changes in the relationship between morphology and Iatitude it was found that there exists a significant positive correlation between species longevity and geographic range. Thus, latitudinal range is related to species duration and cosmopolitan spies with their extended latitudinal distribution and conservative morphoIogy may have the ability to adapt to diverse habitats and may be relatively immune to extinction during pdeoclimatic events that significantly alter the environment. Tempofly, the most common type of morphology in the foraminifera changes indicating that morphological change toward non-conservative morphdogy may be directed evolution away from the conservative morphology of the globigerine and spherical forms.
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