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An exceptionally preserved noncalcified tb.allopb.ytic alga, Menieria minuta gen. nov. et sp. nov. from the uppermost Gun River Formation (middle Aeronian, Lower Silurian) of Anticosti Island, eastern Canada, is characterized by a relatively delicate thallus with a central axis, lateral branches, and helically arranged, regularly and closely spaced, elongate-linguoid appendages. The algae locally constitute an important portion of the biomass in a brachiopod-dominated paleocommunity, forming an algal meadow on a relatively deepwater subtidal setting within the photic zone. This rare fossilization window suggests that such soft algal meadows may have been common during the Early Paleozoic, resembling modern sea grass meadows that are part of the carbon sink. [ABSTRACT FROM AUTHOR]

The Early Silurian carbonate succession of Anticosti Island, eastern Canada, contains a rich and diverse pentameride brachiopod fauna. Multivariate analyses of 91 samples (total 17 230 specimens) confirm a high degree of temporal segregation but only moderate spatial differentiation of the Virgiana, Pentamerus, Stricklandia, Ehlersella, Microcardinalia, and Clorinda communities. Most pentameride communities show a wider range of water depth than previously believed. The V. barrandei Community occupied a substrate setting from lower BA2 to upper BA3, whereas the V. mayvillensis Community lived mainly in BA4. The P. oblongus Community preferred a BA3 setting, comparable to the classic Pentamerus Community, but the P. palaformis Community was predominantly BA4. The stricklandiid communities have a high β diversity, dominated by various species of Stricklandia, Ehlersella, Microcardinalia, and Kulumbella, and occurred most commonly in BA4, but could extend to BA3 environments. The Clorinda Community of Anticosti Island preferred deep and quiet water settings, comparable to its widely accepted BA5 assignment elsewhere. At the generic level, the Virgiana, Pentamerus, and the stricklandiid communities have a largely overlapping BA range, but a clear stratigraphical separation. Thus, their temporal alternations were not likely controlled by water depth, water turbulence, or substrate conditions, but by fluctuating ocean water temperature, as suggested by chemostratigraphical and paleobiogeographical evidence. [ABSTRACT FROM AUTHOR]