Trigonium arcticum (Brightwell) Cleve (Figure 22) Literature: (Hendey 1937, p. 282, pl. 10, fig. 1; Scott and Thomas 2005, p. 18, fig. 2.6a–f).

Description: Length of valve side 148–156 µm, areole 3–3.5 in 10 µm.

Remarks: All specimens observed possessed slightly concave valve sides.

Ecology and distribution: A marine species widely distributed in Antarctica and the Southern seas (Scott and Thomas 2005), also recorded from the sub-Arctic (Scholz and Einarsson 2015). Previously reported as an epiphyte in Potter Cove (Al-Handal and Wulff 2008b). Rare in the material examined.