Mallomonas distinguenda E.S. Gusev, H. Doan-Nhu, L. Nguyen-Ngoc & D. Kapustin, 2016

Gusev, Evgeniy S., Doan-Nhu, Hai, Nguyen-Ngoc, Lam & Kapustin, Dmitry A., 2016, Two new species of the genus Mallomonas from the Cat Tien National Park (Viet Nam): Mallomonas distinguenda and Mallomonas skvortsovii, Phytotaxa 273 (1), pp. 59-64 : 61-62

Mallomonas distinguenda E.S. Gusev, H. Doan-Nhu, L. Nguyen-Ngoc & D. Kapustin sp. nov. ( Figs 1–16 )

Cells dimensions unknown. Scales are small, tripartite. Dome is present on all scales, small, with or without papillae. There is a minute spine beside the dome. Body scales oval-rhombic in form, 2.6–3.2 × 1.7–2.0 μm. Apical scales are slightly asymmetrical, 2.2–2.6 × 1.5–1.9 μm. Proximal border narrow and smooth. Posterior flange smooth. Anterior flange with papillae. V-rib is prominent, smooth. There are two or three rimmed pores in the angle of the V-rib, often placed asymmetrically. Shield with external hexagonal reticulation, each mesh with a small papillae in the center. Papillae also scattered in the angles of reticulum and, especially, along the anterior flanges. This area is raised up above the central part of the shield and flanges, but do not form anterior ribs. Cysts and bristles unknown.

Type: — VIET NAM. Dong Nai Province: Dak Lua swamp in Cat Tien National Park . 11°30’43” N, 107°22’56” E, 10 th of March 2014, leg. E.S. Gusev, sample DL2/3, 10.03.2014, in collection E.S. Gusev. Holotype designated here: Fig. 1 (herbarium IBIW!).

Distribution and habitat:— This species was only found at the type locality.

Etymology:— Epithet refers to the characteristic scale morphology of this species.

Observations: Mallomonas distinguenda was found in a Dak Lua swamp with pH=5.2, temperature 24°C and low conductivity values (10 μS cm-1). Scales of this species were quite abundant in the sample from the swamp, 4–6 per TEM grid.

Figures

FIGURES 1–16. Mallomonas distinguenda sp. nov. TEM and SEM images of scales. Figs. 1–8. Body scales, TEM. Figs 9–12—Apical scales, TEM. Figs 13–16. Body scales, SEM. Note different number and position of rimmed pores: more or less symmetrical at the angle of the V-rib, 2 pores (Figs 1, 2, 13, 15–16) and 3 pores (Fig. 11), strongly asymmetrical along one arm of the V-rib, two pores (Figs 3, 5–9, 12, 14) and three pores (Figs 4, 10). Scale bars: Figs. 2–3, 6–9, 11–12: 2 μm; Figs 1, 4–5, 10, 13–14: 1 μm, Figs 15–16: 0.5 μm