Balnibarbi sombrero Fortey, 1974: 32, pl. 6, fig. 1-4.
HOLOTYPE: Cranidium, PMO NF 835 (figured in Fortey, 1974: pl. 6, fig. 1-2).
TYPE LOCALITY: Profilstranda, Olenidsletta Member, Valhallfonna Formation, Ny Friesland, Spitsbergen, Svalbard.
STRATIGRAPHIC RANGE: Middle of trilobite zone V 1b (Fortey, 1980). This zone coincides with the lower Oepikodus evae conodont zone and Pendeograptus fruticosus graptolite zone within the upper Floian (fig. 1; see also Kröger et al., 2017).
DIAGNOSIS: Balnibarbi erugata species with relatively long (sag.) preglabellar field (>0.35 length of glabella) and smooth exoskeletal surface. Known only from cranidia.