ABSTRACT: Ammolagena clavata (Jones et Parker) – a cosmopolitan agglutinated foraminifera – is present as an accessory taxon in assemblages of the Outer Carpathians. This species has been found in deep water settings, exclusively in rich and diversified assemblages, among taxa representing various strategies of life from epifauna to deep infauna. Ammolagena clavata is one of the most common of attached forms in flysch foraminiferal assemblages and inhabits as a substrate other agglutinated foraminiferal tests. In the Outer Carpathian basins this species wasmore abundant in middle Eocene successions above the carbonate compensation depth (CCD), dominated by mudstones deposited under reduced clastic supply conditions. Ammolagena clavata can be regarded as an indicator of an environment with a low supply of clastic material.