Lower Serpukhovian (Steshevian) foraminifers and algae from exotic limestone clasts of Nötsch (Eastern Alps, Austria)

The > 1,000 m-thick Carboniferous sedimentary succession of Nötsch is divided into the Erlachgraben, Badstub, and Nötsch formations with poorly constrained precise ages, but probably constituting a continuous lithostratigraphic Group deposited from the latest Viséan to the early Bashkirian, thus including a complete Serpukhovian succession. We date the early Serpukhovian (Steshevian) in exotic limestone clasts of the Badstub Fm. based on algae and foraminifers. These limestone clasts have been reworked from a carbonate shelf, indicating that they are older than the Badstub Fm. Microfacies and fossil assemblages indicate that a shallow marine carbonate shelf was developed at the northern margin of the deep-sea basin of Nötsch. The assemblages include the red alga Hortonella, rare green algae, and incertae sedis algae Praedonezella, Aoujgalia, and Frustulata; howchiniid and lasiodiscid foraminifers; atypical endothyrids, probably belonging to Semiendothyra emend.; rare Janischewskina; taxonomically disputable eostaffellids (including Eostaffellina aff. paraprotvae) and pseudoendothyrids; attached forms transitional between pseudolituotubid Fusulinata and calcivertellid Miliolata; and probably the oldest known free Miliolata. Newly described taxa include the incertae sedis algae Praedonezella sebbarae nov. sp. and the foraminifers Pseudoendotaxis nov. gen., Quasilituotuba serpens nov. sp., Q. pseudospiroides nov. sp., and Eoglomospiroides carnica nov. sp. Revised foraminiferal taxa include Pseudolituotubidae, Quasilituotuba cf. serpuchoviensis nov. comb., and Q. ex gr. extensa nov. comb. The studied material provides information about the phylogeny of the first Miliolata and permits the reconstruction of the lineage of Pseudolituotubidae and Calcivertellidae, between the classes Fusulinata and Miliolata. The palaeobiogeography of Austria during the Serpukhovian is not yet clearly established, but relationships with the Saharan and Mediterranean Provinces exist, and especially with the Donbass. Fewer relationships are conspicuous with England, the Moscow Basin or the Urals.