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Previous workers have found that morphological variability recognized in foraminifera is due in part to the effects of environment. The various environmental factors (water depth, temperature, salinity, etc) generally act interdependently, although one factor may be more influential than another in causing observed changes. C. E. Pflum and W. E. Frerichs suggested in 1976, that water depth may be most important in creating shape variation within a genus. Taxonomic problems are inherent, as species may be inaccurately named on the basis of form when, in reality, they actually represent a morphological continuum rather than several biological species.
The multiple rotation method of quantitative shape analysis is a new approach to measuring shapes of foraminifera. The outlines of many foraminifera are digitized, rotated to a standard orientation, and radial measurements are reduced to a few numerical descriptors by factor analysis. The relationship between quantitative morphological variation and environmental factors, such as water depth, are then determined by correlation analysis.
North Atlantic specimens of Cibicides and Uvigerina from 36 stations in 4 transects off Cape Cod were used in this study. Water depths ranged from 100 to nearly 4,200 m. The observed quantitative morphologic changes with depth tend to confirm previous hypotheses of the strong influence of environment. Results of this study may form the basis for a tool useful to paleontologists in making environmental interpretations from microfossil assemblages. Testing of the actual species boundaries is feasible, perhaps aiding in the solution of many taxononic problems.
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