Mastogloia matthaei Pennesi & Poulin

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 : 7

Mastogloia matthaei Pennesi & Poulin Figs 58–61

Section: Ellipticae

Ref. illus.: Pennesi et al. 2013, figs 37–44, 53–56

Samples: GU52P-2

Dimensions: Length 14–15 µm; width 9 µm; striae 24–27 in 10 µm.

Diagnostics: Small oval valves with 3 concave/bilobed partecta on each side, reaching the apex. Quadrangular areolae in irregular longitudinal striae; internal areolae in longitudinal rows (not seen yet in Guam specimens).

Comments: Very similar to M. ovulum Hustedt , M. emarginata Hustedt and M. stellae Pennesi & Poulin in size and shape of the valve and the bilobed partecta. Differs in the shape and arrangement of the areolae from M. ovulum ( Figs 56, 57 ), which has apically elongate areolae tending to form an irregular quincunx pattern and internal areolae not in longitudinal rows (Pennesi et al. 2013, table 1). Distinguished from M. emarginata (see above) in lacking the evident partectal pores and from M. stellae in the striae pattern and shape of the areolae (rectangular and sunken in contrast to round and flush).

Figures

Figures 51–70. Figs. 51–55. Mastogloia emarginata. Figs 51-54. LM views of two specimens focused on valve face and valvocopula, arrowhead indicates one of the prominent exit pores of the partecta (GU44AR-2) (DIC). Fig. 55. Internal view of valve and valvocopula (GU55B-4) (SEM). Figs 56, 57. Mastogloia ovulum specimen at two focal planes (GU44K-6) (DIC). Figs 58-61. Mastogloia matthaei, two specimens at two focal planes (GU52P-2) (DIC). Figs. 62, 63. Mastogloia obliqua, valve at two focal planes (GU66F-4) (DIC). Figs. 64–67. Mastogloia peracuta (GU44AP-9). Figs 64, 65. Specimen at two focal planes (DIC). Figs 65, 66, External views of two specimens in SEM. Figs 68–71. Mastogloia pumila. Figs 68, 69. Specimen in DIC at two focal planes (GU52P-1; catalog # GUD002950). Fig. 70. Internal aspect of valve and valvocopula (GU52P-9) (SEM). Fig. 71. Frustule showing both internal and external valve faces. Scale bars: Figs 51–69 = 5 µm, Figs 70, 71 = 3 µm.