Achnanthes cf. groenlandica (Cleve) Grunow, 1880

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 : 90

Achnanthes cf. groenlandica (Cleve) Grunow ( Figures 43–46 )

Literature: (Witkowski et al. 2000, p. 89, pl. 44, figs. 1–7).

Description: Length 56–82 µm, width 11–15 µm, striae 5–6 in 10 µm.

Remarks: This species looks similar to Achnanthes groenlandica in valve outline, dimensions and striae density, but differs in the shape and size of the central area where it is larger and slightly depressed in the area between raphe proximal endings. Raphe endings penetrate into the central area and not on its outer edge. A similar species has recently been described as epizoic on turtles, Achnanthes squaliformis Majewska et Van de Vijver ( Majewska et al. 2017) but this species possesses denser striae and an axial area pushed to the side on the rapheless valve.

Ecology and distribution: Achnanthes groenlandica is a widely distributed marine species which may live attached to sediment grains or as an epiphyte. Also recorded from the Arctic ( Pearce et al. 2014). Frequent in Potter Cove.

Figures

Figures 39–59: Marine benthic diatoms in Potter Cove, King George Island, Antarctica, summer 2015. (39) Lyrella hennedyi. (40) Petroneis sp. (41) Petroneis plagiostoma. (42) Staurophora sp. (43–46) Achnanthes cf. groenlandica, (43, 44) raphe valve, (45) sternum valve, (46) two cells in girdle view. (47) Cocconeis californica. (48) Cocconeis californica var. kerguelensis. (49) Cocconeis costata var. hexagona. (50) Cocconeis dallmannii. (51) Cocconeis fasciolata. (52) Cocconeis imperatrix. (53) Cocconeis matsii. (54, 55) Cocconeis melchioroides. (56–59) Cocconeis orbicularis, (56, 59) sternum valve, (57, 58) raphe valve.