Early Permian conchostracans from the Fossil-Lagerstätte Bromacker, Thuringian Forest Basin, Germany

Abstract The present study describes carapace valve morphologies of conchostracans (Crustacea) from the Bromacker Horizon (Tambach Sandstone Member, Tambach Formation, Rotliegend Group; Early Permian) of the Bromacker Lagerstätte in the Thuringian Forest Basin (Thuringia, Central Germany). Variations in valve morphology separate two morphotypes. The dominating morphotype 1 is Lioestheria andreevi (Zaspelova, 1968), regarded here as synonymous with Lioestheria monticula Martens, 1983. Much rarer is morphotype 2 with some individuals showing transitions to morphotype 1. Mass occurrence of conchostracans underlines the wet-dry seasonality of the past climate at Bromacker. Preservation of “soft” parts in the postero-dorsal parts of the body occurs in some specimens highlighting the Fossil-Lagerstätte quality of the Bromacker site. The recent radiometric dating of the Bromacker site shifts the lower limit of the “ Lioestheria andreevi – Pseudestheria form Wilhelmsthal assemblage zone” sensu Schneider & Scholze (2018) to the Asselian.