Haslea duerrenbergiana (Hustedt) Sterrenburg, 2015

Sterrenburg, Frithjof A. S., Tiffany, Mary Ann, Hinz, Friedel, Herwig, Wulf E. & Hargraves, Paul E., 2015, Seven new species expand the morphological spectrum of Haslea. A comparison with Gyrosigma and Pleurosigma (Bacillariophyta), Phytotaxa 207 (2), pp. 143-162 : 158

Haslea duerrenbergiana (Hustedt) Sterrenburg , comb. nov.

Basionym:— Navicula duerrenbergiana Hustedt (in Schmidt et al. 1934: pl. 393, figs 8–9).

Observations:— The striae are perpendicularly arranged, the axial and central area are extremely narrow and the valve exterior shows continuous longitudinal fissures, see Pl. 26, fig. 6 in Krammer & Lange-Bertalot 1986. These features are all typical of Haslea .

The data in the protologue of another taxon from the literature, H. indica Desikachary & Prema , are spurious. Desikachary (1988, Pl. 479, fig. 3) shows a broadly lanceolate diatom, one end is capitate and there are two V-shaped transverse hyaline fields on both sides of the central raphe node. All these features are missing from its protologue, which also states that the transverse striae are 10 in 10 μm, the longitudinal “delicate”, meaning much finer. The specimen of plate 479, fig. 3 shows equally fine transverse and longitudinal striae. In other words, the protologue and figure (which does not resemble a Haslea in any feature) do not correspond.