Moralesonia? frauenfeldii (Grunow) D. M. Williams, Ts. Georgiev, T. M. Schust. & C. E. Wetzel

Williams, David M., Georgiev, Tsvetoslav, Schuster, Tanja M. & Wetzel, Carlos E., 2024, The relationships of Eunotogramma frauenfeldii (Bacillariophyta) I. An account of its structure and description of the new genus Moralesonia, Plant Ecology and Evolution 157 (3), pp. 270-290 : 270-290

Moralesonia? frauenfeldii

Figs 9 J , 10

Analysed material.

MOZAMBIQUE • East Africa, Ibo; BM Adams TS 457! ( E. Leonard, no. 7); BM Adams TS 459! ( E. Leonard, two specimens) (figured in Desikachary 1988: pl. 583, figs 2–4, 6, 7); BM Adams F 16! (ex W. A. Firth) (figured in Desikachary 1988: pl. 583, fig. 1); BM Adams GC 1450! (ex W. A. Firth) (Fig. 9 J ).

MAURITIUS • Rodriguez (Île Rodriguez); Stub NHM I 6 (see Fig. 10 A – F ).

Description.

Valves lunate, occasionally fusiform, length 60–65 μm, width 20–25 μm, width ± constant, forming less convex ventral margin. Each valve with two transapical ribs dividing valve into three ± equal parts. Ribs evident externally by clear area, extending through to entire mantle, indicating it as part of valve. Internally raised by 2–3 μm tapering towards mantle edge. Areolae ± round, radiating from eccentric hyaline centre. Rimoportulae absent. Cribra detail not visible or preserved. Girdle unknown.

Figures

Figure 9. A – I. Moralesonia sp. A – C. BM 31716, Brazil, Pernambuco, J. D. Möller [no. 893, 1889], one specimen, scale bar = 20 µm. D, H, I. Fossil material, BM 41317, Payne 7818, United States, California, “ Patos guano ”, specimen 71 × 25 µm, scale bar = 20 µm. E. BM Adams GC 1451, Tempère, Nottingham, specimen 64 × 29 µm, scale bar = 20 µm. F. BM Adams H 885, F. Adams, Hungary, Castel, specimen 72 × 23 µm, scale bar = 20 µm. G. BM 10790, L. H. [ardman] | no. 4001, Philippines, Cebu [“ Zebu ”], one specimen, specimen 64 × 29 µm, scale bar = 20 µm. J. Moralesonia frauenfeldii, BM Adams GC 1450, East Africa, Ibo, ex W. A. Firth, scale bar = 20 µm.

Figure 10. Moralesonia sp., SEM images, specimens from Mauritius, Rodriguez (Île Rodriguez), stub NHM I 6. A. Whole external view of valve, arrows indicate ribs, evident by clear area, extending through to entire mantle, indicating it as part of valve, dividing valve into three ± equal parts, scale bar = 10 µm. B. External view of pole, detail with absence of any pore-field, etc., scale bar = 1 µm. C. Detail of centre of valve, arrows indicating ‘ unadorned’ holes, scale bar = 1 µm. D. Centre of valve with radiating ‘ annulus’ (shown within white box), scale bar = 2 µm. E. External view of pole, with detail of cribra with well-developed, complex volate structure, scale bar = 1 µm. F. Additional external view of pole, with detail of cribra with well-developed, complex volate structure, scale bar = 2 µm.