Compare Neidium iridis
Compare
Neidium dilatatum is distinguished by an elliptic valve outline and multiple (5+), small longitudinal canals. Neidium firmum is much smaller and more narrow.
Large specimens of N. amphigomphous may overlap in size with the smallest specimens of N. iridis. Neidium amphigomphous, however, has distinctly acute, apiculate apices and areolae that become transapically elongate near the valve margin.
Neidium fossum has 2-3 longitudinal lines, subacute apices, and smaller size.
LM scalebar = 10 µm
Length Range
145-261 µm
145-261 µm
Width Range
32-37 µm
32-37 µm
Striae in 10 µm
12-13
12-13
