Gomphoneis rostratoides 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 : 17-19

Gomphoneis rostratoides Q. You & Kociolek , sp. nov. ( Figs 84 –96; figure 84 is holotype)

Type:— CHINA. Little Kalakule Lake , Kunlun Mountains ( SHTU, slide XJ-071016! holotype illustrated in figure 84) .

In LM, valves linear-clavate with a slightly tumid swelling at the center, headpole rounded and footpole rounded. Length 35.8–45.0 µm, breadth 5.9–6.0 µm. Axial area narrow, expanded to form a small, round to elliptical central area, stigmoids wanting. Raphe straight, filiform, with external proximal ends dilated slightly and external distal raphe ends extending straight to the terminus. Internal distal raphe ends are indistinct. Costate striae 12–14/ 10 µm, arched and strongly radiate around the center, with 1–2 shortened striae on either side of the central area. Striae towards the headpole become parallel and nearly convergent towards the terminus. Towards the footpole striae are radiate to parallel. Septa and pseudosepta indistinct. Apical pore fields bisected, distinct at the footpole.

In the SEM, the valve exterior is similar to other species described herein within respect to the striae structure around the center, where striae go from being biseriate to uniseriate (Fig. 92), and elsewhere on the valve. Apical pore fields are bilobed and the porelli appear to be similar in size or even larger than the puncta, and forming distinct rows (Fig. 93). The raphe is deflected slightly at the poles (Figs 91, 93), but the distal ends do not extend all the way to the end of the mantle (Fig. 93). The same is true for the valve interior, where the apices have prominent helictoglossae and pseudosepta (Figs 94, 96) and apical pore fields have thin subdivisions (Fig. 96). The central striae have internal thickenings around the uniseriate portion of the striae and the central nodule has the proximal raphe ends that are deflected in the same direction (Fig. 95).

Etymology:— The species is named for its rostrate headpole.

Distribution and ecology:— Little Kalakule Lake, Kunlun Mountains, Xinjiang, China, altitude 3300m, pH 9.0, collected in the wetland near the lake (summarized in Table 1).

Figures

PLATE 14, FIGURES 84–90. Gomphoneis rostratoides, LM. Valve views showing size diminution series. Figure 84 is the holotype. Scale bar = 10 µm for all figures.