The taxonomic status of the minute foraminifera Discorbina minutissima Chaster (1892), D. chasteri Heron-Allen & Earland (1913) and related species

Abstract. This study presents a revision, using type material, of the tiny foraminifera Discorbina minutissima Chaster, D. chasteri Heron-Allen & Earland (erected as a nomen novum for D. minutissima Chaster, non Seguenza) and D. chasteri var. bispinosa Heron-Allen & Earland. All are referred to the genus Rotaliella Grell. Heron-Allen & Earland’s new name chasteri is shown to be only applicable as a replacement name for Chaster’s species; their own material from Clare Island is a new species, named here R. heronalleni sp.nov. In addition, two other species — Rotaliella ? simplex (Sidebottom) and R. antarctica sp.nov. — have been recognised amongst the specimens labelled as D. chasteri in the Heron-Allen & Earland Collection in the Natural History Museum (BMNH). Lectotypes are designated for Rotaliella chasteri and R. bispinosa.