Species Description: Cells are small, mostly elliptical, and nearly hyaline in light microscopy. The prominent axial rib adjacent to the raphe is usually the only visible feature. An extensive study by Schoeman et al. (1976) showed a more plastic valve morphology. The valves have radiate striae that may be composed of single puncta rows that coalesce and become fimbriate near the margins (Schoeman et al. 1976), or the entire stria may be fimbriate (Fig. 1, TEM). Intercalated between the striae are 1-3 shorter, reduced radial striae not reaching the valve median. An axial rib encloses the raphe, which lacks terminal fissures. Most valves have 1-3 elongate pores adjacent to the central nodule (Fig. 1); these are usually present on both valves, sometimes on one valve, or lacking entirely (Hargraves & Guillard 1974). The size is about 9-12µm in length, and about 4-6µm wide, with 70-80 striae in 10µm
More recently, the taxonomic status has been changed to Fistulifera pelliculosa (Brébisson) Lange-Bertalot (see Lange-Bertalot 2001), but most records refer to the species as a Navicula. Apparently, it has a wide geographic distribution but is seldom recorded. Since it grows very well in vitro, it has frequently been used in physiological studies. It is easy to overlook in live samples, but appears to be rare in the IRL. Most U.S. records are from freshwater of high mineral content, though it survives well in coastal ponds in the New England area (Hargraves & Guillard 1974)
Hargraves PE, Guillard RLL. 1974. Structural and physiological observations on some small marine diatoms. Phycologia 13: 163-172.
Lange-Bertalot, H. 2001. Navicula sensu stricto. 10 Genera separated from Navicula sensu lato. Frustulia. Diatoms of Europe: diatoms of the European inland waters andcomparable habitats. Vol. 2 pp. 1-526: ARG Gantner Verlag KG.
Schoeman FR, Archibald REM, Barlow DJ. 1976. Structural observations and notes on the freshwater diatom Navicula pelliculosa (Brebisson ex Kützing) Hilse. Brit Phycol J 11: 251-263.