Placoneis anglophila

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)).