THE APPLICATIONS OF STROMATOPOROID PALEOBIOLOGY IN PALEOENVIRONMENTALANALYSIS

Stromatoporoids are epibenthic calcified sponges in many Phanerozoic ( especially Palaeozoic) reef, and reef-related environments, and may be used as tools for all scales of palaeoenvironmental analysis. Palaeoz oic stromatoporoid classification uses the calcified skeleton, and alt hough higher level taxa may be convergent, genera and species are norm ally readily identifiable and have palaeobiological utility. A hierarc hical growth-form classification of stromatoporoids comprises: Level 1 (outline forms: laminar, tabular, domical, columnar, bulbous, defined with ratio limits; and dendroid, expanding conical, digitate and irre gular); Level 2 (ornament, as papillae, mamelons and protuberants, giv e an increasing degree of disruption of the outline); and Level 3 (gro wth patterns of smooth and ragged margins, enveloping and non-envelopi ng laminations, coalescence and anastomosing). Inappropriate growth fo rm terms in current use are rejected, especially massive and encrustin g. Stromatoporoid palaeobiology applied at local scale aids determinat ion of relative degree of contemporaneous turbulence and sedimentation ; community scale study of stromatoporoids promotes comparisons betwee n palaeoenvironments in reef and reef-related facies. Palaeozoic strom atoporoids may aid regional and even global event recognition, includi ng changes in ocean states. Major gaps in knowledge are growth rates, and whether stromatoporoids were photosensitive and/or photosymbiotic.