Cocconeis imperatrix A. Schmidt

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 : 91-92

Cocconeis imperatrix A. Schmidt ( Figure 52 )

Literature: (Al-Handal and Wulff 2008b, p. 426, figs. 46– 49; Manguin 1960, p. 305, figs. 358, 359; Riaux-Gobin and Romero 2003, p. 28, figs. 29–31, pl. 20, figs. 1–7, pl. 21, figs. 1–8).

Description: Length 38–65 µm, width 25–44 µm, striae (raphe valve) 3–4 in 10 µm.

Remarks: Scott and Thomas (2005) considered Cocconeis imperatrix as a synonym of Cocconeis fasciolata . Studying valve structure of both taxa in Potter Cove revealed noticeable variation between them so that it can be considered to be a separate entity (Al-Handal and Wulff 2008b).

Ecology and distribution: A marine species mostly reported from Antarctica. Common in Potter Cove.

Cocconeis matsii (Al-Handal, Riaux-Gobin et Wulff) Riaux-Gobin, Compère, Romero et Williams ( Figure 53 ) Literature: (Al-Handal et al. 2010, p. 6, figs. 13–18, 25–34 as C. pinnata var. matsii ).

Description: Length 10–13 µm, width 5–7 µm, striae (rapheless valve) 7–8 in 10 µm.

Remarks: This species was originally described from Potter Cove as C. pinnata var matsii but was considered a distinct species based on stria and areola density and structure ( Riaux-Gobin et al. 2003). These authors, however, did not provide images for specimens but rather established a new combination.

Ecology and distribution: The species has not been reported outside its type locality in Potter Cove. Frequent in the material examined.

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.