Post-extinction recovery and diversification of reef-dwelling brachiopod communities: Examples from the lower Silurian of Hudson Bay Basin, Canada

摘要: Abstract Ziegler's (1965) early Silurian brachiopod community zones and Boucot's (1975) Benthic Assemblages have been instrumental in determining the structures of early–middle Paleozoic level-bottom communities, but are difficult to apply reef ecosystems due mixing assemblages these systems. In this study, Shannon Simpson diversity levels were calculated for reef-dwelling faunas from several North American one European localities. Reef-dwelling collapsed at end Ordovician did not recover until mid-Aeronian when modest appeared higher tropics. brachiopods achieve high Telychian reefs invaded paleoequatorially located Hudson Bay Moose River basins. The Attawapiskat Formation (Telychian) contains earliest known coral-stromatoporoid complex with associated high-diversity faunas. These separated into nine associations through clustering principal component analyses. can be further grouped a level-bottom-type cryptic-type based on dominant taxa, levels, average shell size, substrate type. Surprisingly, large species Pentameroides septentrionalis was able thrive relatively flat open spaces inter-reef areas among frame-building corals stromatoporoids within cores. absence Stricklandia is water temperature equatorial seas which too warm by cool-water dependent genus. addition, presence deep-water Clorinda Gypidula shallow-water explained lack hurricane-grade storms region, would comparable quiet-water conditions below storm wave base latitudes.