Hydrosera whampoensis

The valve face is flat, with a deep mantle and broad cingulum. In valve view, the valve margin is in the shape of two superimposed triangles. Porefields, containing pseudocelli, are positioned at the three apices of one of the apparent triangles. The valve face is triangular with pseudocelli positioned between each apex. Pseudoseptae are present. The areolae are loculate, externally with,large irregularly spaced foramina. Internally, the areolae open in small pores arranged in radial rows. Short spines may be visible in LM distal to the pseudocelli. A single, large rimoportula is present.

Hydrosera whampoensis and H. triquetra have been confused with one another. In fact, their differences have been variously recognized (Skortzow 1930, Hustedt 1938, Voigt 1939, Frenguelli 1953, Qie et al. 1982). At this time, the taxa are each considered to be distinct species, based on size of the external foramina and undulate margins (Qi et al. 1982). Reports of H. triquetra appear, instead, to be aligned with H. whampoensis (Simonsen 1965, Li and Chiang 1977 and Fungladda 1982). Hydrosera whampoensis is considered to be widespread in higher conductivity waters of lower latitudes, while H. triquetra is restricted to tropical, saline waters (Qi et al. 1982).