Nitzschia australis (M. Peragallo) A. Mann

Al-Handal, Adil Y., Torstensson, Anders & Wulff, Angela, 2022, Revisiting Potter Cove, King George Island, Antarctica, 12 years later: new observations of marine benthic diatoms, Botanica Marina (Warsaw, Poland) 65 (2), pp. 81-103 : 96

Nitzschia australis (M. Peragallo) A. Mann ( Figures 94, 95 , 118 )

Literature: ( Mann 1937, p. 63, pl. 6, fig. 1; Peragallo 1921, p. 65, pl. 3, figs. 17, 18 as N. dubia var. australis ; Scott and Thomas 2005, p. 187, fig. 2.107a–f).

Description: Length 70–85 µm, width 7–10 µm, fibulae 14– 16 in 10 µm.

Remarks: Striae are very fine but look coarser at valve center. Both Peragallo and Mann (cited above) reported 19– 20 striae in 10 µm while Scott and Thomas (2005) recorded 19–25 in 10 µm. The observed specimens appeared to have less dense striae. This Antarctic species has rarely been reported and described in recent literature.

Ecology and distribution: Antarctic marine species. Rare in Potter Cove.

Figures

Figures 93–106: Marine benthic diatoms in Potter Cove, King George Island, Antarctica in summer 2015. (93) Nitzschia angularis. (94, 95) Nitzschia australis. (96) Nitzschia mitchelliana. (97) Nitzschia cf. gelida. (98) Nitzschia hybrida. (99) Nitzschia cf. obtusa. (100) Nitzschia sigma. (101) Nitzschia sp. (102) Entomoneis gigantea. (103) Entomoneis kjellmanii. (104) Entomoneis paludosa. (105) Surirella fastuosa. (106) Surirella sp.

Figures 113–118: SEM images of the marine benthic diatoms in Potter Cove, King George Island, Antarctica, summer 2015. (113, 114) Cocconeis orbicularis, external and internal faces of sternum valve. (115, 116) Fragilariopsis cylindrus, internal valve sides. (117) Entomoneis paludosa. (118) Nitzschia australis.