Balnibarbi erugata erugata Fortey, 1974

Hopkins, Melanie J., 2019, Phylogenetic analysis and revision of the trilobite subfamily Balnibarbiinae (Olenidae), American Museum Novitates 2019 (3928), pp. 1-1 : 1-

Balnibarbi erugata erugata Fortey, 1974

Figure 2A–D, E

Balnibarbi erugata Fortey, 1974: 31 , pl. 5, fig. 1-10.

HOLOTYPE: Cranidium, PMO NF 3016 (figured in Fortey, 1974: pl. 5, fig. 1-3).

TYPE LOCALITY: Profilstranda, Olenidsletta Member, Valhallfonna Formation, Ny Friesland, Spitsbergen, Svalbard.

STRATIGRAPHIC RANGE: Throughout trilobite zone V 1c and the very beginning of V 2a ( Fortey, 1980). These zones coincide with the upper Oepikodus evae and lower Oepikodus intermedius conodont zones, and the Didymographtus protobifidus graptolite zone within the upper Floian (fig. 1; see also Kröger et al., 2017).

DIAGNOSIS: Balnibarbi erugata subspecies with relatively short (sag.) preglabellar field (<0.35 length of glabella) and fine granulation present on glabella, axial, palpebral, and posterior border furrows, and on frontal area adjacent to anterior border furrow.

Figures

FIGURE 2. Balnibarbi erugata Fortey, 1974, close-ups. A. Balnibarbi erugata erugata, holotype cranidium, PMO-NF-3016. Note exfoliation of frontal area and glabella. Arrow points to terrace lines on anterior border that are expressed on both the external surface and internal mold. B. Anterior border of Balnibarbi erugata erugata, CAMSM F3976, showing faint caeca and very fine granulation on frontal area near anterior border furrow and terrace lines on border. C. Posterior border furrow on Balnibarbi erugata erugata, CAMSM F3976, showing very fine granulation. D. Occipital ring of Balnibarbi erugata erugata, PMO-NF-695, showing very fine granulation on glabella. E. Balnibarbi erugata erugata PMO-NF-772. Arrows point to select pits in anterior border furrow; specimen is exfoliated. F. Balnibarbi erugata sombrero, PMO-NF-2054. Arrows point to select pits in anterior border furrow on exfoliated surface. Scale bars = 1 mm.