Mallomonas spinosa Gusev, 2012

Gusev, Evgeniy S., 2012, A new species of the genus Mallomonas (Synurophyceae), Mallomonas spinosa sp. nov., from Vietnam, Phytotaxa 66 (1), pp. 1-5 : 2-3

Mallomonas spinosa Gusev , sp. nov. ( Figs 2–11 )

Cells ellipsoidal, approximately 20 × 11 µm, covered by scales with spines ( Fig. 2 ). Apical scales lack spines ( Fig. 4 ). Body scales oval, 4.5–5.6 × 2.7–3.6 µm. Shield with densely and regularly spaced papillae ( Figs. 6–11 ). V-rib conspicuous, acute to slightly rounded. Distal ends of arms of V-rib curve and become continuous with anterior submarginal ribs. Anterior submarginal rib forms a prominent asymmetrically placed stout spine with four edges ( Fig. 7 ). Anterior flange with a row of papillae ( Fig. 8 ). Posterior flange smooth with depression containing pores on the base plate ( Figs. 5–11 ). Posterior rim wide and smooth in SEM view. Bristles unknown. Cysts not observed.

Type: — VIETNAM. Dong Nai Province: unnamed temporary forest pool in Cat Tien National Park , 11°24’26” N, 107°24’48” E, 23 November 2010, E.S. Gusev s.n. SEM stub CT40/2010 (holotype IBIW!, see Fig. 2 ), sample CT40 23.11.2010, in collection E.S. Gusev .

Distribution and habitat:— This species was found in the type locality and two other water bodies in Khanh Hoa province in Vietnam.

Etymology:— The epithet “spinosa” refers to the whole cell being covered by scales with stout spines.

Figures

FIGURES 2–11. Mallomonas spinosa sp. nov. Fig. 2: Whole cell covered by scales bearing spines (holotype). Fig. 3: More detailed view of the body scales. Fig. 4: More detailed view of the apical part of the cell. Fig. 5: Bottom view of the base plates of the scales showing distinct group of small pores in the proximal part. Fig. 6: Scale without spine. Fig. 7: Lateral view of the scale, four-edged spine in top view. Fig. 8: Scale with distinct row of papillae on the anterior flange. Fig. 9: Scale showing further variation in the size of the depression containing pores on the base plate. Figs 10, 11: Low-silicified scales. Scale bars: Fig. 2: 5 µm; Figs. 3–4: 2 µm; Figs. 5–11: 1 µm