Dead or alive? Brachiopods and other shells as substrates for endo- and sclerobiont activity in the early Devonian (Lochkovian) of the Barrandian (Czechia)

Twelve encrusters and three endobiont trace fossils were distinguished on silicified brachiopod, coral and gastropod shells coming from the Kotýs Limestone (Lochkovian) of the Prague Basin, Bohemia. Encrusters preferred larger and costellate brachiopod shells with prominent convexity of valves. Locations and developments of coral encrustations produced by tabulate Aulopora sp., rugose Syringaxon sp., and an unnamed rugose coral indicate different strategies in selection of substrate. The auloporid preferred living host, articulated shells or intact valves, the rugose corals were less selective and colonised also dead and broken shells. Unlike encruster associations of middle and upper Devonian age in other areas (France, Poland, USA), in Bohemia, the encruster hosts were chiefly orthids (Parmorthina Havlíček, 1975; Isorthis Kozłowski, 1929; Dalejina Havlíček, 1953; Resserella Bancroft, 1928) and atrypids (Spinatrypa Stainbrook, 1951). Apart from corals, a microproblematicum Allonema Ulrich & Bassler, 1904, two pterobranchs, bryozoans, a hederellid, a craniid, a protorthid brachiopod, and a microconchid were observed on host shells together with small dendritic borings, cylindrical borings of Trypanites Mägdefrau, 1932, and a dendritic structure of unclear origin. • Key words: bioerosion, encrusters, Brachiopoda, Aulopora, Allonema, Lochkovian.