Pliensbachian large-terebratulid beds: taphonomic signatures and paleoecological drivers (Southern Alps, Italy)

The Lower Jurassic shallow-water carbonate platforms settings of the northern Tethyan margins hosted diverse marine communities including bivalves, corals, small benthic foraminifera, echinoderms, gastropods, brachiopods and floras (dasycladalean algae). The aftermath of the Triassic–Jurassic biotic crisis witnessed the appearance of important new groups such as the large lituolid foraminifera and the lithiotid bivalves which are also present. Extraordinary examples of these benthic invertebrates occur in a unique Pliensbachian carbonate platform succession, the Trento Platform (Southern Alps), where they occupied a complex mosaic of habitats within a lagoon system. In the Pliensbachian of the Trento Platform sedimentary successions, the large-sized terebratulid brachiopods (Lychnothyris rotzoana (Schauroth, 1865)) formed localized monospecific shell beds, occurring within the Orbitopsella Zone. The goals of this study include (1) the characterization of the sedimentological and taphonomic features of these large-brachiopod beds and (2) their paleoecological interpretation with respect to both the proliferation and demise of these brachiopods.