Mallomonas cattiensis E.S. Gusev, H. Doan-Nhu & L. Nguyen-Ngoc, 2015

Gusev, Evgeniy S., Doan-Nhu, Hai & Nguyen-Ngoc, Lam, 2015, Mallomonas cattiensis, sp. nov. (Synurales, Chrysophyceae), a new species from Viet Nam, Phytotaxa 221 (2), pp. 188-192 : 189

Mallomonas cattiensis E.S. Gusev, H. Doan-Nhu & L. Nguyen-Ngoc , sp. nov. ( Figs 2–22 )

Cells dimensions unknown. Scales are tripartite, thick. Base plate with small pores. A patch of pores is in the angle of the V-rib ( Figs 6, 17–18 ). Body scales with or without dome, oblong-oval 4.9–6.6 × 2.7–3.4 μm. Shield with 9–13 transverse ribs connected by struts, with a single row of pores between them and with 1–3 depressions ( Figs 7, 10, 13 ). Dome with ribs ( Figs 2, 5, 8–10 ). V-rib acute ( Figs 7–10 ), continuous with the anterior submarginal rib ( Fig. 19 ). Anterior flange with thick secondary layer in form of lobate structures (7–10). Proximal border wide, covering the posterior flange and often overlapping the V-rib. Caudal scales with stout spines ( Figs 14–17 ), 3.5–3.6 × 2.0–2.3 μm. Apical scales are short and asymmetric, 4.1–4.5 × 2.0–2.5 μm ( Figs 11, 13 ). Cysts unknown.

Type: — VIET NAM. Dong Nai Province: Ta Lai reservoir in Cat Tien National Park. 11° 23’ 16” N, 107° 21’ 03” E, E. S. Gusev, 10 th March 2014, SEM stub TL1/2014 (holotype IBIW!, see Fig. 10 , sample TL1 10.03.2014, in collection E.S. Gusev. Isotype: SEM stub TL1, sample TL1 10.03.2014, in DMP collection at Oceanographic Museum, Institute of Oceanography, Viet Nam)

Distribution and habitat:— This species was found in the type locality and in a forest stream (11° 23’ 32” N, 107° 22’ 11” E) in Cat Tien National park.

Etymology:— Epithet “cattiensis ” refers to the fact that the species was first found in Cat Tien National Park ( Viet Nam).

Observations: Mallomonas cattiensis was found in a Ta Lai reservoir with pH=6.4, low conductivity values (37 μS cm-1) and high temperature (30 °C). Scales of this species were quite abundant in the samples from the reservoir, 4–6 per TEM grid.

Figures

FIGURES 2–22. Mallomonas cattiensis, sp. nov.TEM and SEM images of different types of scales. 2–3. Domed body scale with different focus, TEM. 4–5. Domed body scales, TEM. 6. Domeless body scale, TEM. 7. Domeless body scale, SEM. 8–9. Domed body scales, SEM. 10. Domed and domeless body scales, SEM. 11. Apical scale, SEM. 12. Domeless scale, SEM. 13. Group of scales, SEM. 14–16. Caudal scales, SEM. 17. Caudal scale, bottom view, SEM. 18. Domed body scale, bottom view, SEM. 19. Domeless body scale, lateral view, SEM. 20, 22. Bristles, SEM. 21. Bristle with domeless scale, SEM. Scale bars: 2–6, 13: 2 μm; 7–12, 14–22: 1 μm.