Auricula flabelliformis Voigt

Lobban, Christopher S., 2015, Benthic marine diatom flora of Guam: new records, redescription of Psammodictyon pustulatum n. comb., n. stat., and three new species (Colliculoamphora gabgabensis, Lauderia excentrica, and Rhoiconeis pagoensis), Micronesica 2015 (2), pp. 1-49 : 3

Auricula flabelliformis Voigt Figs 10–12

Syn.: A. machutchoniae Giffen (1970b)

Ref. illus.: Voigt 1960, pl. 1, figs 8, 9; Ricard 1977, pl. 8, fig. 2; Ricard 1987, fig. 942

Samples: Guam: GU66A-2; Yap: Y26B

Dimensions: Length 92–95 µm, width 64–67 µm, striae ca. 19 in 10 µm; fibulae ca. 8 in 10 µm.

Diagnostics: Large, broadly reniform valve, dorsal margin (defined by the raphe-keel) forming>90% of the circumference, indented from the valve margin before the ventral ends; ventral margin very short, straight. Striation flabellate, arising along a poorly defined median line.

Comments: Observed so far as only a single SEM specimen from Guam and an LM specimen from Yap. Voigt named three varieties besides the type in which the pattern of striae along the median axis ranged from flabelliform to distichous ( var. hustedtii ), the latter based on Meister’s (1932, pl. 10, fig. 67) Hustedtia mirabilis , now Auricula mirabilis (Meister) Paddock & Sims (1980) .

Figures

Figures 10–12. Auricula flabelliformis. Figs 10, 11. LM and SEM images of specimens from Yap (Y26B) (DIC) and Guam (GU66A-2) (SEM). Only half of each image is shown so that the delicate striation is visible. Fig. 12. Detail of internal valve face showing very short ventral surface and flabelliform striation (GU66A-2) (SEM). Fig. 13. C. fastuosus large valve (GU66F-8, catalog # GUD002914) (DIC). Figs 14, 15. C. fastuosus small valve (Fig. 14) compared to S. scalaris (GU52Q-2, GU52Q-10b respectively) (DIC). Scale bars: Figs 10, 11, 13–15 = 10 µm, Fig. 12 = 5 µm.