Figure 4
SEM images of Paralia marina . Epitype specimens, B40 0040792. (A-C) Mantle view. (A) Uru1. Profile of smooth and spineless separation valve with obscured fenestrae. (B) Helgo1. Interlocking noduliform protrusions of sibling separation valves. (C) Helgo3. Weakly silicified intercalary valves showing areolae perforating basal silica layer (arrow), siliceous outcroppings (black arrowheads) and external pores of rimoportulae (white arrowhead) which are usually more spaced apart than on this specimen; fenestrae unobscured. (D) Helgo1. Internal valve view with rimoportulae (arrow) and striae pores (arrowhead). Scale bars = 2 μm (A,C), 1 μm (B,D).