Diploneis puellafallax

Valves elliptical or more often linear–elliptical with bluntly rounded apices. Length 15–30 μm, breadth 9–14.5 μm. Length–to–breadth ratio 1.7–2.1. Raphe filiform, straight with slightly marked central ends and inconspicuous distal ends. Narrow depressions flanking the internal raphe slit. Axial area as a whole is very narrow, linear. Central area is very small, hardly expanded circularly or elliptically, without any recognizable H–shaped appendices (horns). The internal longitudinal canals on either side are narrow, marked externally by a row of indistinct puncta. Transapical striae are radiate throughout, more strongly near the ends, appearing comparatively coarse, 11–13 in 10 μm, being composed of two rows of opposed to alternating areolae, 22–26 in 10 μm. SEM external and internal view, see Figs 130–133. External view (Fig. 133) exhibits a slightly curved raphe slit with shortly bent central ends depressed into the valve surface and a small, gently deflected distal groove. A differentiated terminal fissure is lacking. Cribra above underlying canals appear somewhat irregularly distributed, uni– to biseriate; cribra of adjacent striae appear more closely condensed, biseriate to finally confluent onto the barely differentiated mantles. Internal view with uncorroded closing membranes see Fig. 132, after corrosion see Figs. 130–131. The relief of canals, central nodule and virgae is rather high. The raphe slit lying in a narrow, particular raphe rib is separated from the canals by depressions which appear as dark lines in LM view. In open alveoli the areolae are arranged opposed biseriate closer to the canals, becoming gradually alternating and finally even triseriate at valve margins.

• Author
  Lange-Bert. and Fuhrmann 2016
• Length Range
  15-30 µm
• Width
  9-14.5 µm
• Striae in 10µm
  11-13