Section: Ellipticae Ref. illus.: Hustedt 1931 – 1959, fig. 896; Pennesi et al. 2013, figs 65, 66 (lectotype specimen) Samples: GU 44 R- 2, GU 44 AU- 1; GU 53 E- 2; GU 66 F- 4; GU 55 B- 4 Dimensions: Length 18 – 20 µm; width 9 – 13 µm; striae 20 – 23 in 10 µm; partecta 2 in 10 µm. Diagnostics: Small oval valves with 3 – 4 concave partecta on each side, reaching the apex, pore on the outer side of each partectum distinctively visible in LM (Fig. 54, arrows). Longitudinal striae nearly straight, coarser than the transapical striae, resulting in rectangular areolae. Comments: Differs from M. ovulum Hustedt, which has finer, circular areolae, and partectal pores that are not evident in LM. As noted in the errata to Lobban et al. (2012), the specimen given there in pl. 33, figs 9, 10 for M. ovulum was misidentified and is given here correctly as M. emarginata; the specimen of M. ovulum posted on the web in its place is printed here as Figs 56, 57; see Jordan et al. 2009 – 2015, / taxa _ id / 585541, for SEM images of M. ovulum. Besides the unique pores, M. emarginata differs from M. ovalis A. Schmidt in having partecta reaching the apex and from M. matthaei (see below) and M. stellae (Pennesi et al. 2013, figs 45 – 52, 57 – 60) in the number of partecta as well as characters of the areolae.
Sumber: 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)