Gomphoneis eriensioides Kulikovskiy, Kociolek & Solak, 2013

Kociolek, John P., Kulikovskiy, Maxim S. & Solak, Cüneyt N., 2013, The diatom genus Gomphoneis Cleve (Bacillariophyceae) from Lake Baikal, Russia, Phytotaxa 154 (1), pp. 1-37 : 8

Gomphoneis eriensioides Kulikovskiy, Kociolek & Solak , sp. nov. ( Figs 61–84 , 397–400)

Valves lanceolate-clavate, with apices rounded. Length 26.0– 67.5 µm, breadth 8.5–13.0 µm. Axial area straight, expanded to form an irregularly rounded central area, with 3–5 shortened striae on either side. 4 stigmoids present around the central area. Raphe lateral, more or less straight with external proximal ends dilated and round. External distal raphe ends extend straight onto the valve mantle. Costate striae strongly radiate, except near the headpole where they approach being parallel. Striae 11–14/ 10 µm. Apical pore fields evident, comprised of distinct rows of porelli. Septa and pseudosepta present at the poles.

In the SEM the valve exterior has evident striae composed of two rows of areolae (Figs 397–399). The stigmoidal openings around the central area appear to be in small, round depressions (Figs 397, 398). Proximal raphe ends dilated (Figs 397, 398). Apical pore field porelli are organized into double rows, and appear like condensed striae ( Fig. 399). Internally, there are pseudosepta and helictoglossae at the poles. The smallish central nodule has recurved proximal raphe ends at its margin, and there are 4 isolated stigmoids around the base. Stigmoids may be unoccluded, or have small teeth-like projects (Fig. 400).

Type:— RUSSIA: Bolshoi Ushkaniy Island (rock), Lake Baikal, N52 o 35.694, E107 o 17.141, white stone cape, on stone, 16.07.2011, leg. M. Kulikovskiy ( IBIW slide no. 18575m, holotype designated here (= Fig. 63 ); COLO slide no. 18575p, SZCZ slide no. 18575°, isotypes) .

Etymology: — Gomphoneis eriensioides is named for its superficial resemblance to G. eriense.

Observations:— Gomphoneis eriensioides differs from G. eriense by having 4 stigmoids rather than a single stigma, undifferentiated apical pore fields rather than those composed of differentiated porelli, and lack of longitudinal lines on either side of the axial area as seen in G. eriense (Patrick & Reimer 1975; Kociolek & Stoermer 1988).

Figures

PLATE 4: LM. Figs 61–84: Gomphoneis eriensioides sp. nov. Fig. 63 is of the holotype. Figs 85–88: G. cf. eriensioides. Scale bar = 10 µm for all figures.