Visit us at

Diatoms of the United States is now known as Diatoms of North America.
This site has been redesigned and updated, and will be closing soon.

Neidiomorpha binodiformis

(Krammer) Cantonati, Lange-Bert. and Angely 2010      Category: Symmetrical biraphid
BASIONYM: Neidium binodiforme Krammer 1985

REPORTED AS: Neidium binode (Patrick and Reimer, pg. 404, Pl. 37, Fig. 6) 

Navicymbula pusilla


Neidiopsis hamiltonii

LM scalebar = 10 µm = 80 pixels.


Contributor: Sergio Mendoza - June 2015
Length Range: 20-35 µm
Width Range: 7-8 µm
Striae in 10 µm: 25-28


Valves are linear-elliptical and biundulate, with constricted central margins and rostrate apices. Striae are uniseriate, coarse, and parallel at the central area becoming weakly radiate near the apices. Areolae are transapically elongate near the raphe, becoming circular near the margin of the valve. A narrow longitudinal canal borders the valve margin. The central area is asymmetric and oval. The axial area is narrow and linear. The raphe is straight. The proximal raphe ends are straight, or deflected slightly to the primary side.

Note that this taxon was described (Krammer 1985) based on Neidium binodis sensu Germain 1981, as distinct from N. binodis (Ehrenberg) Hustedt. The original material of N. binodis (Ehrenberg) Hustedt, however, has not been examined and such work may change the standing of these two species.

Also note that Patrick and Reimer (1966) illustrate a taxon that conforms to N. binodiformis, but is named Neidium binode. It is likely that many of the North American reports do not distinguish, or confuse, these two species.

Original Description

Basionym: Neidium binodiforme
Author: Krammer 1985
Length Range: 16-33 µm
Width Range: 5-8 µm
Striae in 10 µm: 24-28

Original Description

Original Images

Cite This Page:
Mendoza, S. (2015). Neidiomorpha binodiformis. In Diatoms of the United States. Retrieved May 26, 2018, from

Species: Neidiomorpha binodiformis

Contributor: Sergio Mendoza

Reviewer: Dennis Vander Meer


Asencio, A. and Aboal, M. (2000). A contribution to knowledge of chasmoendilithic algae in cave-like environments. Algological Studies 98: 133-151.

Cantonati, M. Lange-Bertalot, H. and Angeli, N. (2010). Neidiomorpha gen. nov. (Bacillariophyta): A new freshwater diatom genus separated from Neidium Pfitzer. Botanical Studies 51: 195-202.

Liu, Q., Kociolek, J.P, Wang, Q. and Fu, C. (2014). Valve morphology of three species of Neidiomorpha (Bacillariophyceae) from Zoigê Wetland, China, including description of Neidiomorpha sichuaniana nov. sp. Phytotaxa 166 (2): 123–131. 0.11646/phytotaxa.166.2.3

Round, F. (1958). Observations on the diatom flora of Braunton Burrows, N. Devon. Hydrobiologia, 11(2), 119-127.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Neidiomorpha binodiformis CAS

North American Diatom Ecological Database (NADED)


Autecology Discussion

Neidiomorpha binodiformis was found in a benthic collection from Cold Creek, San Bernadino County in southern California. It was also found in samples from the Spirit Lake fish hatchery, Dickinson County, Iowa. According to Cantonati et al. (2010), xxxxxxxxxxxxxxxx