Humidophila brekkaensis (Petersen) R.L. Lowe et al., 2014

Chattová, Barbora, Lebouvier, Marc & Vijver, Bart Van De, 2018, Morphological and taxonomical analysis of the terrestrial diatom genus Humidophila (Bacillariophyta) on Ile Amsterdam and Ile Saint-Paul (Southern Indian Ocean), Phytotaxa 336 (1), pp. 28-42 : 31

Humidophila brekkaensis (Petersen) R.L. Lowe et al. ( Figs 1–17 )

Morphological observations:—Valves linear, slightly gibbous at the central area, with convex margins, and bluntly rounded apices. Valve dimensions (n=20): length 7.5 – 18.0 μm, width 3.0–4.5 μm. Raphe filiform, straight with simple straight proximal and distal endings. Striae parallel throughout the entire valve, 28 – 33 in 10 μm, easily resolved with a light microscope. In SEM, striae composed of one transapically elongated areola. Mantle areolae rounded, slightly elongated near the apices, interrupted at the apices. Girdle composed of three copulae, perforated by a series of transapically elongated slits. In contrast to other Humidophila species, mantle areolae not separated from the valve face by an edge but positioned on the same level as the areolae of the valve face.

Ecology and associated diatom flora: —Most H. brekkaensis valves have been found in moss samples, almost exclusively taken from the driest mosses ( Campylopus Brid. ) (F-value: VIII) or on liverworts, usually occurring with Eunotia paludosa Grunow (1862: 22) , Frustulia lebouvieri Van de Vijver & Gremmen (2006: 435) , Pinnularia microstauron ( Ehrenberg 1843b, pl. 1/4, fig. 1) Cleve (1891: 28), Luticola beyensii , and other Humidophila species.

Figures

FIGURES 1–17. Humidophila brekkaensis (Petersen) R.L.Lowe et al. Light (LM) and scanning electron micrographs (SEM). 1–13. LM of valve views. 14. SEM of an entire valve (externally). 15. SEM girdle view. 16–17. SEM of an entire valve (externally). Note the mantle areolae positioned on the same level as the areolae of the valve face. LM scale bar = 10 μm. SEM scale bars = 5 μm, 1