Triceratium dubium Brightwell, 1859

Park, Joon Sang, Lobban, Christopher S. & Lee, Kyun-Woo, 2018, Diatoms associated with seaweeds from Moen Island in Chuuk Lagoon, Micronesia, Phytotaxa 351 (2), pp. 101-140 : 103

2. Triceratium dubium Brightwell Fig. 3

References: Simonsen (1974), p. 27; Navarro (1981b), p. 619, figs 52–54; Navarro & Lobban (2009), p. 130, figs 21–24.

Samples: Moen2_ Halimeda

Dimensions: 21.2–26.1 μm along a side of triangle.

Diagnostics: Small six-pointed cells with three points bearing ocelli and three with external rimoportulae; loculate valve structure.

Comments: This small Triceratium is distinctive and ubiquitous. T. dubium differs from congeners in the region in having six angles but ocelli on only half of them; other species have 2–5 angles all with ocelli ( T. dictyotum , T. pulchellum ) or 4 angles, two with ocelli ( T. bicorne ).

Class Mediophyceae (Jousé & Proshkina-Lavrenko) Medlin & Kaczmarska

Subclass Thalassiosirophycidae Round & R.M. Crawford

Figures

FIGURES 2–8. Seven diatom species of Coscinodiscophyceae and Mediophyceae. Fig. 2. Roperia tesselata. Fig. 3. Triceratium dubium. Fig. 4. Thalassiosira cf. cedarkeyensis. Fig. 5. Ardissonea formosa. Fig. 6. Climacosphenia elongata. Fig. 7. Toxarium hennedeyanum, Fig. 8. T. undulatum. Scale bar = 10 μm.