Neidium distinctepunctatum

Valves are lanceolate, with bluntly apiculate apices. Longitudinal lines, formed by canals, are present along each valve margin. The longitudinal canals terminate prior reaching the apices. The axial area is narrow and linear. The central area is variable in development, from small and oval in the smallest specimens to transversely elliptic or nearly quadrangular in larger specimens. The proximal raphe ends vary from obliquely to distinctly hooked. Striae are slightly radial, becoming parallel to convergent at the apices. Areola density is 11-14 in 10 µm.

Some features are only visible under critical LM, or under SEM. For example, as in other Neidium taxa, the distal raphe ends are bifurcate and possess an apical flap (Hamilton et al. 1996). Features of the taxon include external “depressions” of the valve associated with the areolae and a network of "braided" silica on the interior of the valve. The only other taxon that has this internal complex network of braiding silica is N. boyeri Reimer. The internal proximal raphe ends terminate in a narrow linear-undulate central nodule, termed a rectelevectum (Van de Vijver et al. 2010). Externally, the raphe terminates in an elliptic, slightly raised helictoglossa.