Neidiopsis weilandii is larger and has more linear valves, with cuneate to subrostrate apices as compared to N. wulffii. Valves of N. vekhovii are smaller, with triundulate margins. Neidiopsis hamiltonii and N. levanderi have straight, rather than deflected, proximal raphe ends. Species in the genus Neidium have proximal raphe ends that are hooked to opposite sides of the valve.