Anorthoneis vortex Sterrenburg Slide BM 1987
Creators: name: Pennesi, Chiara
name: Majewska, Roksana
name: Sterrenburg, Frithjof A. S.
name: Totti, Cecilia
name: Stefano, Mario De
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Chromista
Ochrophyta
Bacillariophyceae
Achnanthales
Cocconeidaceae
Anorthoneis
Anorthoneis vortex

description: Anorthoneis vortex Sterrenburg 1987: 16 (Figs 112–129)   
 References:— Sterrenburg (1987), p. 15, 4 figs; Sterrenburg (1988), p. 375, pl. 1, figs 5, 7, pl.2, figs 8–15, pl. 5, figs 30–35; Hein (1991) figs 22–24, 25–28; Witkowski et al. (2000), pl. 42, figs 23–25.   
 Description. Valves broadly elliptical to almost circular in outline (Figs 116, 122). Apical axis: 14–16 μm, transapical axis: 11–12 μm.   
  SV:—  Externally, valve face flat, becoming convex near the undifferentiated wide mantle, which terminates in a reduced marginal area (Figs 116, 117). The eccentric sternum, very narrow, not well discernible, not reaching the valve margin and lacking terminal areas (Figs 116, 117). In the valve centre, corresponding with an asymmetrical, irregular hyaline area, reduced and imperforated areolae are present (Figs 116 arrow, 118). Transapical striae radiate 20–22 in 10 μm, uniseriate on the entire valve surface and composed of small, circular areolae, 22–24 in 10 μm, externally occluded by hymenes with small, radially distributed perforations (Fig. 118). Virgae not raised. On the valve margin, close to the end of each stria, a smaller imperforated areola is present (Figs 117–119 arrow). Internally, sternum narrow, thickened, expanding into irregular hyaline central area, with slightly raised small central nodule (Figs 120, 121). Virgae raised on both the valve face and the mantle (Fig. 121).   
  RSV:—  Externally, valve face flat to convex, with concave mantle (Figs 122, 123). Raphe sternum asymmetric, developed entirely within the valve face (Figs 122, 123). Proximal raphe endings expanded, pore-like, converge on a short, strongly asymmetric central area (Figs 122, 123, 126). Distal raphe endings similar in shape to the central ones terminate in roundish terminal areas, distant from the valve margin (Fig. 127). Striae radiate, 22–24 in 10 μm, uniseriate on the valve face, becoming biseriate on the mantle (Figs 122, 127), composed of small circular areolae (22–24 in 10 μm) occluded by hymenes ultrastructurally similar to those in the SV. As in the SV, a smaller areola is present on the valve margin, close to the end of each biseriate stria (Figs 127, 129 arrows). Internally, both the raphe-sternum and the central nodule thickened and prominent (Fig. 125). Proximal raphe endings deflected in opposite directions and hooked (Fig. 128). Distal ones terminate in reduced helictoglossae hardly reaching the hyaline terminal areas (Fig. 129). Valvocopula open, with a smooth inner margin (Figs 125, 129).
description: Published as part of Pennesi, Chiara, Majewska, Roksana, Sterrenburg, Frithjof A. S., Totti, Cecilia & Stefano, Mario De, 2018, Taxonomic revision and morphological cladistics analysis of the diatom genus Anorthoneis (Cocconeidaceae), with description of Anorthoneis arthus-bertrandii sp. nov., pp. 201-238 in Phytotaxa 336 (3) on page 227, DOI: 10.11646/phytotaxa.336.3.1, http://zenodo.org/record/13720104