REVISION OF THE ORDER STROMATOPORIDA

The genus Stromatopora has been widely misinterpreted as characterized by vertical structural elements, but the type species, Stromatopora c oncentrica, has a structure, here called cassiculate. dominated by obl ique elements like a chainlink fence. Only twenty-six species of the s everal hundred attributed to Stromatopora conform to a redefinition of the genus presented here. Cellular microstructure is distinct from mi croreticulate microstructure. As presently defined the Order Stromatop orida is polyphyletic. Genera that have cellular microstructure are pl aced in the redefined Order Stromatoporida and evolved from unknown an cestors in Llandovery time. Genera that have microreticulate microstru cture are separated as the Order Syringostromatida (emended), that evo lved from densastromatid ancestors about the same time. In a major epi sode of adaptive radiation starting in the Pridoli and culminating in Emsian time the ancestral syringostromatid, Parallelostroma, gave rise to Coenostroma, Habrostroma, Syringostroma, Columnostroma and Paralle lopora. In late Early to Middle Devonian time Stromatopora radiated in to Lineastroma, Arctostroma, Pseudotrupetostroma, Glyptostromoides and Taleastroma. The position of Ferestromatopora is problematic. Syringo stromella coexisted with Stromatopora in Middle and Late Silurian time and gave rise to Salairella in late Early Devonian time. Concise defi nitions of all these genera are formulated, problems of distinguishing them are discussed, and representative species are listed.