Turriplaca triangula (Thomsen, 1978) Cavalier-Smith, 2012
syn.: Pinaciophora triangula Thomsen, 1978
Diagnosis: Cells globose to ovoid, 39-42 µm in diameter. Plate-scales triangular, with slightly concave sides (1.5-1.7 µm long) and rounded tips. The plate-scales have (2-)3(-4) holes in the upper plate. The spine-scales have a remarkable structure: they consist of a hollow tube (0.3-0.4 µm diameter halfway along the spine and 0.24-0.16 µm at the base; spine length: 0.8-1.5 µm), broadened towards its apex, terminating in a trumpet-like opening (0.5-0.7 µm). The tube itself is surrounded by four smaller tubular structures, each 0.21-0.23 µm in diameter and 0.35 µm long, connected to the central spine by tapering lamellae up to 2/3 of the spine-length. The base of the spine is not circular but octagonal. The spine base and the 4 tubular appendices are perforated by many minute holes.
Ecology: The species is known from both brackish and fresh water, and reported from Sweden (inland water, Thomsen, 1978; estuary of the Swedish river Mörrum and 5 km up that river, Siemensma, 1991), Canada (Nicholls, 1983) and the Baltic, along the southern coast of Sweden (Siemensma, 1991). Type locality: Lake Straken (Sweden).