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Pseudofallacia monoculata

(Hust.) Liu, Kociolek and Wang 2012      Category: Symmetrical biraphid
BASIONYM: Navicula monoculata Hust. 1945
SYNONYM(S): Fallacia monoculata (Hust.) D.G.Mann 1990 

Psammothidium subatomoides


Pseudofallacia tenera

LM scalebar = 10 µm = 80 pixels.


Contributor: Ian Bishop - March 2016
Length Range: 9-16 µm
Width Range: 4-5.2 µm
Striae in 10 µm: 22-24


Valves are elliptic to lanceolate, with broadly rounded ends. The central area is small and circular. The raphe is curved slightly, within a narrow axial area. Striae are radiate. A longitudinal hyaline area is present on each side of the axial area. A conopeum is present along the axial margin, and is expanded and slightly asymmetric at the center of the valve.

Original Description

Basionym: Navicula monoculata
Author: Hust. 1945
Length Range: 14 µm
Width Range: 5 µm
Striae in 10 µm: 24

Original Description

Original Images

Cite This Page:
Bishop, I. (2016). Pseudofallacia monoculata. In Diatoms of the United States. Retrieved May 23, 2018, from

Species: Pseudofallacia monoculata

Contributor: Ian Bishop

Reviewer: Eduardo A. Morales


Hustedt, F. (1945). Diatomeen aus Seen und Quellgebieten der Balkan-Halbinsel. Archiv für Hydrobiologie 40(4):867-973.

Krammer, K. and Lange-Bertalot, H. (1985). Naviculaceae Neue und wenig bekannte Taxa, neue Kombinationen und Synonyme sowie Bemerkungen zu einigen Gattungen. Bibliotheca Diatomologica 9:5-230, 43 pls.

Liu, Y., Kociolek, J.P., Fan, Y. and Wang, Q. (2012). Pseudofallacia gen. nov., a new freshwater diatom (Bacillariophyceae) genus based on Navicula occulta Krasske. Phycologia 51(6): 620–626.

Mora, D., Carmona, J. and Cantoral-Uriza, E.A. (2015). Epilithic diatoms in the Upper Laja River Basin, Guanajuato, Mexico. Revista Mexicana de Biodiversidad 86(4): 1024-1040. 10.1016/j.rmb.2015.09.004

Round, F.E., Crawford, R.M. and Mann, D.G. (1990). The Diatoms. Biology and Morphology of the Genera. Cambridge University Press, Cambridge, 747 pp.

Links & ID's

Index Nominum Algarum (INA)

Transfer INA
Original INA

California Academy of Sciences (CAS)

Pseudofallacia monoculata CAS

North American Diatom Ecological Database (NADED)


Autecology Discussion

Recent USGS stream surveys have collected Pseudofallacia monoculata in several localities across the United States, from Georgia, North Carolina and Virginia in the east to the Willamette Valley, OR in the west. This taxon has also been observed in central Mexico (Mora et al. 2015). It is widely distributed but found in low abundance where collected.