Entomoneis paludosa (W. Smith) Reimer

Long, Ji-Yan, Williams, David M., Liu, Bing, Mo, Wen-Hui & Quan, Si-Jin, 2022, Ultrastructure of three Species of Entomoneis (Bacillariophyta) from Lake Qinghai of China, with reference to the external areola occlusions, PhytoKeys 189, pp. 29-50 : 29

Entomoneis paludosa (W. Smith) Reimer

Figs 11 , 12 , 13 , 14

Observation.

LM (Fig. 11 ). Frustules panduriform in girdle view (Figs 11A-D ). Frustule dimensions (n = 19): length 34.2-80.7 μm, width 12.8-21.8 μm at constricted part, 22.4-30.3 μm at widest part. Keel high. Hymen strip region distinct, worm-like (i.e. curved from apex to valve centre, widest near distal end), located close to the raphe canal (Fig. 11A-D , indicated in Fig. 11C , see also Fig. 12A, B and D ). Junction line slightly sinuous (Fig. 11 , see also Fig. 12A ). Striae visible under LM, 22-25 in 10 μm. Girdle bands numerous.

SEM (Figs 12 and 13 ). Frustule panduriform, composed of epivalve, girdle bands and hypovalve (Fig. 9A and B ). Junction line confirmed same as LM observation (Fig. 12A , dotted line). Costae mostly running from raphe canal to mantle. Hymen strip region composed of costae and hymen strips (Fig. 12A and D , two arrows, respectively). This type of hymen strip belongs to Type One hymen strip, which are a siliceous membrane strip perforated by irregularly distributed round pores (Fig. 14E ). Mantle thickened (Fig. 12C , arrow). Cells having a 4:2 configuration of girdle bands, i.e. four girdle bands associated with epivalve and two associated with hypovalve (Fig. 12C-E , labelled in Fig. 12E ). Fibulae having only two levels: raphe fibulae and basal fibulae (Fig. 13A and B , two arrows, respectively). Internally, one cell bearing only one lumen, no sub-compartment present (Fig. 13C-F ).

Ecology and distribution.

Entomoneis paludosa was commonly found on the stone surfaces in Lake Qinghai with E. sinensis and E. qinghainensis and it has a global distribution. Entomoneis paludosa is a dominant species in the sampling sites.

Figures

Figure 9. A-C Entomoneis qinghainensis sp. nov., frustule view, SEM A one complete frustule, note the undulate junction line (indicated by dotted line) and the hymen strip region B detail from Fig. A note the striae composed of many single areolae near the sternum and two costae merging into one (arrow) C detail from Fig. A note hymen strips (two arrows). Scale bars: 10 μm (A); 2 μm (B, C).

Figure 11. A-K Entomoneis paludosa, girdle view, LM A-D four complete frustules, note the hymen strip region (indicated in Fig. C) E-K seven valves in side view showing size reduced series. Scale bar: 20 μm.

Figure 12. A-E Entomoneis paludosa, girdle view, SEM A one whole frustule, note the worm-like hymen strip region and the junction line (indicated by the dotted line) B another frustule C-E details from Fig. B note the thickened mantle (Fig. C, arrow), worm-like hymen strip region (Fig. D, two arrows) and 4: 2 configuration of the girdle bands (i. e. four girdle bands associated with epivalve (EV) and two associated with hypovalve (HV) (Fig. E). Scale bars: 10 μm (A, B); 2 μm (C-E).

Figure 13. A-F Entomoneis paludosa, valve side view, SEM A-C three valves in side view, note the basal fibulae and the frustule cavity without sub-compartments (indicated by double-headed arrow) D-F details from Fig. A-C. Scale bars: 10 μm (A-C); 2 μm (D-F).

Figure 14. A-F Details of hymen and hymen strip in Entomoneis, SEM A, B details of hymen strip of Type Two from E. sinensis sp. nov., note the two rows of linear pores (Fig. A, two arrows) on either side of the two intermittent rows of rounded pores (Fig. A, wavy arrow) C, D details of hymen strip of Type One from E. qinghainensis sp. nov., note the hymen is finely perforated over both the areolae (Fig. D arrow) and the hymen strips (Fig. D, double-headed arrow) E detail of hymen strip of Type One from E. paludosa, note the hymen is finely perforated over both the areolae and the hymen strips (double-headed arrow) F detail of hymenes from E. triundulata, note the hymenes of the areolae in the girdle bands (two arrows). Scale bars: 600 nm (A-F).