Anorthoneis hyalina Hustedt 1955
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 hyalina

description: Anorthoneis hyalina Hustedt 1955: 15 (Figs 68–87)   
 References:— Hustedt (1955), pl. 2 figs 3–4, pl. 5 figs 12–13; Foged (1975), pl. 7, figs 12, 13; Simonsen (1987), p. 404, pl. 604, figs 1–8; Witkowski et al. (2000), p. 98, pl. 51, fig. 1; Garcia & Talgatti (2006), figs 3–4, 9–15.   
 Description. Valves ovoid to circular in outline (Figs 76, 81). Apical axis: 24–36 μm, transapical axis: 20–28μm.   
  SV:—  Externally, valve face flat in its central part, distally convex, curving gradually into a shallow undifferentiated mantle (Figs 76, 78). Sternum strongly asymmetric, expanded in the centre, giving rise to a very large, semi-circular central area, occupying more than 2/3 of the entire valve surface (Figs 76, 78), covered with randomly scattered, irregular concavities and flanked by groove-like fissures (Figs 78, 79 arrow). Similar irregular, apically elongated groove-like fissures mark the apical axis (Figs 76, 78). Striae uniseriate, radiate, 9–11 in 10 μm close to the valve centre, becoming denser towards the margin (15–17 in 10 μm), composed of slit-like areolae (10 in 10 μm) internally occluded by vela (Fig. 80). The internal areola openings are larger than those on the exterior. Internally, almost undiscernible sternum and very large hyaline central area appear heavily silicified and smooth (Fig. 77).   
  RSV:—  Externally, valve face concave with slightly raised asymmetrical raphe-sternum (Figs 81, 84). Valve mantle wide, terminating at the valve margin in a narrow marginal area bordered by a thickened rim; same thickening occurs on valvocopula (Figs 82, 85 arrows); ligulate structures are visible on the valvocopula (Fig. 85, black arrow). Striae radiate and strongly radiate near the apices (Figs 81, 82), 17–18 in 10 μm, uniseriate, becoming biseriate on the mantle (Figs 82, 85, 87). Circular areolae almost equal in size, 30 in 10 μm, occluded by perforated hymenes. A smaller, nonhymenate areola is present on the valve margin, at the end of each stria (Fig. 85, white arrowhead). Asymmetric central area small, subtriangular (Figs 81, 83). Raphe branches straight with close, coaxial, and slightly expanded proximal endings, deflected slightly to one side (Figs 81, 83). Distal raphe endings straight, slightly expanded, hardly reaching sub-circular terminal areas, distant from the valve margin (Fig. 82). Internally, both the raphe-sternum and the central nodule thickened and prominent (Fig. 86). Distal ones end in reduced helictoglossae, not reaching the hyaline terminal areas (Fig. 86).
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 pages 219-221, DOI: 10.11646/phytotaxa.336.3.1, http://zenodo.org/record/13720104