Mastogloia obliqua Hagelstein Figs 62, 63

Ref. illus.: Hagelstein 1939, pl. 5, figs 12, 13; Giffen 1980, pl. 2, figs 23, 23a, 24; Loir & Novarino 2013, pl. 16c

Samples: GU66F-4

Dimensions: Length 13 µm, width 4.4 µm, striae ca. 25 in 10 µm.

Diagnostics: Small, rostrate valves with one partectum on each side (sometimes two, as shown by Hagelstein 1939), placed slightly obliquely across the central area.

Comments: Comparable with M. tenuis Hustedt (Lobban et al. 2012, pl. 37, figs 6–8), which is not rostrate, has finer striae, and has two small tapering partecta bordering the larger partecta on each side, the chambers symmetrically placed (as in most Mastogloia spp.) and also has axial costae bordering the internal raphe-sternum. Also similar to M. giekesii Cholnoky (Loir & Novarino 2013, pl. 13a), which is rostrate, has two chambers on each side (apparently never only one), symmetrically placed.