New and emended species of Jurassic planktonic foraminifera

Abstract

Two Jurassic planktonic genera are emended and two new species and one subspecies of Jurassic planktonic foraminifera are defined. The genera are Globuligerina Bignot and Guyader 1971 and Conoglobigerina Morozova 1961 and the two new species are Globuligerina tojeiraensis Gradstein and Conoglobigerina grigelisi Gradstein. Both new species commonly occur in the Tojeira Formation, Montejunto, Portugal. The Tojeira Formation is a deeper marine shale unit of Early Kimmeridgian age. The new subspecies is Globuligerina oxfordiana calloviensis Gradstein, from the Callovian in the Crimea and Ukraine. A detailed description is provided for one of the historically oldest Jurassic taxa, Conoglobigerina helvetojurassica Haeusler 1881, re-discovered in the Birmenstorfer Schichten of Middle Oxfordian age near Monthal, Canton Aargau, Switzerland. A neotype is proposed for this taxon. One specimen of C. helvetojurassica may have been attached to a substrate during a later part of its life cycle. The same Birmenstorfer Schichten also yielded two small specimens of an unknown planktonic genus with longitudinal ribs along its pyramidal and probably triserial test. The test is microperforate and wall textures reticulate. The types and type locality of ‘Globuligerina’ stellapolaris Grigelis, described from Northwestern Russia should be carefully investigated, to determine if it is a Late Jurassic or a Late Cenozoic taxon.