The earliest brachiopod-bryozoan dominated community in the Ordovician of peri-Gondwana and its ancestors: a case study from the Klabava Formation (Arenigian) of the Barrandian, Bohemia

A remarkably rich fossil assemblage with bryozoans, orthid and lingulate brachiopods, siliceous sponges and other fauna is described from the uppermost layers of the Klabava Formation (Arenigian) in the western part of the Prague Basin, Bohemia. Its taxonomic composition is evaluated and its depth and local position toward the ancient shore line is discussed. The fossil assemblage probably represents transported material from a fissure in the steep rock walls of the shore cliff. The life assemblage was probably analogous to Recent cryptic communities of the rocky shore. The species Quadrotheca sp. is described, representing the earliest known orthothecid hyolith in the Ordovician of the Prague Basin.