Placoneis anglophila

(Lange-Bert.) Lange-Bert. in Metzeltin, Lange-Bert. and García-Rodríguez 2005      Category: Symmetrical biraphid
BASIONYM: Navicula anglophila Lange-Bert. 1987
SYNONYM(S): Navicula pseudanglica (Lange-Bert.) in Krammer and Lange-Bert. 1985 

Placoneis amphibola


Placoneis explanata

LM scalebar = 10 µm = 80 pixels.


Contributor: Eilleen Salas | Ian Bishop | David R.L. Burge | Mark Edlund - June 2015
Length Range: 18-21 µm
Width Range: 7.5-8.5 µm
Striae in 10 µm: 9-10


Valves are elliptical, with rostrate to subcapitate apices. Striae are punctate, slightly curved and radiate. Near the center valve, 1-2 striae may be shorter in length than the remaining striae. The axial area is narrow. The central area is small and nearly round. The proximal raphe ends are straight and slightly expanded.

Navicula anglophila is similar to Placoneis elginensis, but P. elginensis has linear valve margins according to the original description of Pinnularia elginensis (Gregory 1856). Re-examination of the lectotype specimen of Placoneis elginensis by Cox (2003) also found P. elginensis valves are linear with a transverse central area.

The species illustrated on this taxon page was first proposed as Navicula pseudanglica Lange-Bertalot in Krammer and Lange-Bertalot (1985). In 1987, Lange-Bertalot recognized that his N. pseudanglica was a later illegitimate homonym of Navicula pseudanglica Cleve-Euler (1948). To correct the nomenclatural issue, Lange-Bertalot proposed the nom. nov., Navicula anglophila Lange-Bertalot in Lange-Bertalot and Krammer (1987) for his Navicula pseudanglica Lange-Bertalot (1985). However, Cox (Diatom Research issue is dated Dec 1987, but INA lists the date as 1988) transferred the taxon to Placoneis as Placoneis pseudanglica (Lange-Bertalot) Cox 1988. Subsequent workers have treated that name as either a valid transfer P. pseudanglica (Lange-Bertalot) Cox (see Cox 2003, Hofmann et al. 2013) or as a nom. nov. for N. pseudanglica as P. pseudanglica Cox (see CAS, Algaebase).

In 2005, Lange-Bertalot recognized that his taxon belonged in the genus Placoneis and proposed its transfer as P. anglophila (Lange-Bertalot) Lange-Bertalot in Metzeltin et al. (2005), based on his recognition of N. anglophila Lange-Bertalot in Lange-Bertalot and Krammer (1987) as the legitimate nom. nov. Lange-Bertalot (2005) recognized Cox’s Placoneis pseudanglica (Lange-Bertalot) Cox as invalid, which it is not, rather he should have referred to P. pseudanglica (Lange-Bertalot) Cox as illegitimate. It seems that the jury has fallen on the side of recognizing this taxon as P. pseudanglica Cox 1987/1988? as the proper name, but because Cox’s transfer was actually dated 1988 (as noted by CAS and INA), there was a legitimate and validly published available name in place for this taxon, i.e. Navicula anglophila Lange-Bertalot in Lange-Bertalot and Krammer (1987), for which Cox should have based her transfer. Because Lange-Bertalot published his nom. nov. (Navicula anglophila Lange-Bertalot) before Cox’s 1987/1988? transfer to Placoneis (essentially superfluous nom. nov), we have to accept the Lange-Bertalot’s (2005) transfer to Placoneis as the correct name for this taxon, i.e. Placoneis anglophila (Lange-Bertalot) Lange-Bertalot in Metzeltin et al. (2005).

Had Cox published her combination Placoneis pseudanglica Cox before Lange-Bertalot published his new name (Navicula anglophila Lange-Bertalot), her name Placoneis pseudanglica Cox would have priority as a nom. nov. based on ICN Art 41.8 (see example 21(c)).

Original Description

Basionym: Navicula anglophila
Author: Lange-Bert. 1987
Length Range: 26-40 µm
Width Range: 10.5-15 µm
Striae in 10 µm: 9-10 in the center valve, up to 14 at the ends

Original Description

Original Images

Cite This Page:
Salas, E., Bishop, I., Burge, D., and Edlund, M. (2015). Placoneis anglophila. In Diatoms of the United States. Retrieved April 25, 2018, from

Species: Placoneis anglophila

Contributor: Eilleen Salas | Ian Bishop | David R.L. Burge | Mark Edlund

Reviewer: Sarah Spaulding


Cleve-Euler, A. (1948). Süsswasserdiatomeen aus dem Feuerland von Prof. Väinö Auer Gesammelt. . Acta Geographica 10: 3-6.

Cox, E.J. (1987). Placoneis Mereschkowsky: the re-evaluation of a diatom genus originally characterized by its chloroplast type. Diatom Research 2: 145-157. 10.1080/0269249X.1987.9704994

Cox, E.J. (2003). Placoneis Mereschkowsky revisited: resolution of several typification and nomenclatural problems, including the generitype. Bot. J. Linn. Soc. 141: 53–83. 10.1046/j.1095-8339.2003.00115.x

Gregory, W. (1856). Notice of some new species of British Fresh-water Diatomaceae. Quarterly Journal of Microscopical Science, new series, London 4:1-14, pl. I.

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.

Metzeltin, D., Lange-Bertalot, H. and García-Rodríguez, F. (2005). Diatoms of Uruguay. Compared with other taxa from South America and elsewhere. In: H. Lange-Bertalot (ed.), Iconographia Diatomologica. Annotated Diatom Micrographs. Vol. 15. Taxonomy-Biogeography-Diversity. A.R.G. Gantner Verlag K.G. 15:736 pp.

Links & ID's

Index Nominum Algarum (INA)

Transfer INA

California Academy of Sciences (CAS)

Placoneis anglophila CAS

NCBI Genbank Taxonomy


North American Diatom Ecological Database (NADED)


Autecology Discussion

Placoneis anglophila was found in epipelon in Beck’s Canal and in epipsammic samples from Silver Lake, both in Dickinson Co., Iowa. According to Cox (2003) it is found in slightly eutrophic to eutrophic freshwater.


Distribution of Placoneis pseudanglica in rivers of the continental U.S. based on the National Water Quality Assessment program. Retrieved 03 June 2015.

Credit/Source: USGS BioData

EMAP Assessment

The Environmental Protection Agency (EPA) western Environmental Monitoring and Assessment Program (EMAP) study was completed during the years 2000-2004 (see citations at bottom of this page). Over 1200 streams and rivers in 12 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming) were selected for sampling based on a stratified randomized design. This type of design insures that ecological resources are sampled in proportion to their actual geographical presence. Stratified randomized design also allows for estimates of stream length with a known confidence in several “condition classes” (good or least-disturbed, intermediately-disturbed, and poor or most-disturbed) for biotic condition, chemistry and habitat.

EMAP Distribution

Placoneis anglophila

EMAP Response Plots

Placoneis anglophila

EMAP citations

Results are published in:

Johnson, T., Hermann, K., Spaulding, S., Beyea, B., Theel, C., Sada, R., Bollman, W., Bowman, J., Larsen, A., Vining, K., Ostermiller, J., Petersen, D. Hargett, E. and Zumberge, J. (2009). An ecological assessment of USEPA Region 8 streams and rivers. U.S. Environmental Protection Agency Region 8 Report, 178 p.

Stoddard, J. L., Peck, D. V., Olsen, A. R., Larsen, D. P., Van Sickle, J., Hawkins, C. P., Hughes, R. M., Whittier, T. R., Lomnicky, G. A., Herlihy, A. T., Kaufman, P. R., Peterson, S. A., Ringold, P. L., Paulsen, S. G., and Blair, R. (2005). Environmental Monitoring and Assessment Program (EMAP) western streams and rivers statistical summary. U.S. Environmental Protection Agency Report 620/R-05/006, 1,762 p.

Stoddard, J. L., Peck, D. V., Paulsen, S. G., Van Sickle, J., Hawkins, C. P., Herlihy, A. T., Hughes, R. M., Kaufman, P. R., Larsen, D. P., Lomnicky, G. A., Olsen, A. R., Peterson, S. A., Ringold, P. L., and Whittier, T. R. (2005). An ecological assessment of western streams and rivers. U.S. Environmental Protection Agency Report 620/R-05/005, 49 p.