Recently completed studies on the morphology, fine-structure, taphonomy, and functional morphology of stalks of living crinoids provide the necessary information to reexamine the morphology and function of stalks of Paleozoic crinoids. Patterns of stalk morphology will be documented by describing the distribution of connective tissue (ligaments) in the stalks of Paleozoic taxa. This will be done by examining the microstructure (stereom) of columnals, and by interpreting taphonomic patterns of fragmented stalks. The morphological data will then be used in a functional analysis of crinoid stalks, with the stalk modeled as a cantilever beam. A modified model for large beam deflections which we have developed and tested will allow us to examine how different stalk architectures responded to different energy regimes. These results will serve not only as a paleoecological tool, to reinterpret, for example, the distributional patterns of crinoids among different environments, but should also provide new characters (types and patterns of positioning of connective tissue) for testing hypotheses of relationship among higher crinoid taxa.
