Figure 1. Rhopalodia brebissonii collected from Taylor Creek, Fort Pierce, Florida. Light micrograph
Figure 2. Rhopalodia brebissonii collected from the St. Lucie estuary, Florida. SEM.
Rhopalodia brebissonii Krammer in Lange-Bertalot & Krammer 1987
The valves are strongly asymmetrical in the apical axis, broadly elliptical, dorsal margin highly convex, ventral margin straight or slightly concave (Fig. 1) with rounded protracted apices. Cell length is 15-40µm, breadth 5-9µm. The raphe is positioned along the dorsal margin (Fig. 2). Costae are parallel in the center, radiate towards the apices, and number 3-6/10µm. Two to five striae are located between two costae; the striae number 17-22/10 µm
Nominally a freshwater species, R. brebissonii is rare and probably enters the IRL via the drainage canals. It has a worldwide distribution; its occasional description as a coastal marine species may also be a result of freshwater introduction.