Gomphoneis basiorobusta Q. You & Kociolek, 2013

You, Qingmin, Kociolek, John Patrick & Wang, Quanxi, 2013, New Gomphoneis Cleve (Bacillariophyceae: Gomphonemataceae) species from Xinjiang Province, China, Phytotaxa 103 (1), pp. 1-24 : 12-13

Gomphoneis basiorobusta Q. You & Kociolek , sp. nov. ( Figs 55 –66; figure 56 is holotype)

Type:— CHINA. Kalakule Lake , Kunlun Mountains ( SHTU, slide XJ-071018! holotype illustrated in figure 56) .

In LM, valves lanceolate-clavate, tumid at the center, tapering to rounded headpole and footpole, the footpole is slightly wider than the headpole. Length 28.5–52.0 µm, breadth 5.0– 8.2 µm. Axial area narrow, broadening to form a bow-tie shaped central area. Stigmoids wanting. Central area bordered by 2–3 shortened striae on either side. Raphe straight, slightly lateral, with external proximal ends dilated and extending slightly into the central area, internal proximal raphe ends tightly recurved. External distal raphe ends extend straight to the valve terminus, while internal distal raphe ends are positioned well from the valve terminus. Costate striae arched and strongly radiate about the center, becoming parallel to slightly convergent towards the headpole, parallel to radiate towards the footpole. Striae number 13–15/ 10 µm. Septa and pseudosepta present. Apical pore fields distinct.

In the SEM, G. basirobusta has very similar valve morphology with the species with which it is found. Striae are composed of two rows of small, round puncta. Around the center of the valve the striae taper and have single rows of puncta (Fig. 64). At the footpole, the apical pore field porelli are round like the puncta and also distinctly organized into double rows (Fig. 66). The raphe has a subtle dilation at the proximal ends (Fig. 64), and is slightly deflected before bisecting the bilobed apical pore fields (Fig. 66).

Internally, the center of the valve shows recurved proximal raphe ends situated on a small, linear central nodule (Figs 61, 62). Striae can be seen to be singly punctate around the center (Fig. 62). The internal structure of the single rows of puncta are more pronounced, bordered by thickenings (Fig. 62). At each apex a prominent pseudoseptum and helictoglossa is present (Figs 63, 65). The apical pore field has structural separations of porelli, creating double rows similar to, but more condensed than, the striae (Fig. 65).

Etymology:— The species is named for its pronounced footpole.

Distribution and ecology:— Kalakule Lake, Kunlun Mountains, Xinjiang, China, altitude 3600m, pH 8.6, collected in the lake by plankton net. (summarized in Table 1).

Figures

PLATE 10, FIGURES 55–60. Gomphoneis basirobusta, LM. Valve views showing size diminution series. Figure 56 is the holotype. Scale bars = 10 µm for all figures.