Mallomonas teres Nemcova & Kapustin, 2019

Nemcova, Yvonne & Kapustin, Dmitry, 2019, Mallomonas teres, sp. nov. (Chrysophyceae), simultaneously revealed in two distant European peat-bog regions, Cryptogamie, Algologie 20 (4), pp. 35-39 : 37

Mallomonas teres Nemcova & Kapustin , sp. nov.

( Fig. 1 )

HOLOTYPE SPECIMEN. — Single scales on a TEM grid deposited at the Culture Collection of Algae of Charles University, Prague, H2018/1. Fig. 1A shows a representative scale from the specimen.

TYPE LOCALITY. — Sweden, Wästerbotten County, Gärdvikmyrorna peat-bog, (63.48733°N, 19.71048°E), 20 m a.s.l., sample collected by Y. Nemcova M. Skaloudova M. Pusztai and J. Neustupa, 3. VI.2012.

ETYMOLOGY. — The epithet refers to the rounded distal part of the scale, from Latin “teres” (rounded, rotund).

HABITAT. — Small peat-bog pool.

DISTRIBUTION. — Sweden, in addition to the type locality, the species was also found in the Bärmyran peat-bog (63.51733°N, 19.71472°E); Ukraine, mire pool in block 32 of Selezivka forestry in the Polessian Nature Reserve (51.53503°N, 28.08763°E).

DESCRIPTION

Body scales 4.9-5.1 × 2.7-3.2 Μm, with evenly distributed pores on the basal plate, except for the dome area ( Fig. 1 ). Posterior rim is encircling half of the perimeter of the scale. A continuous submarginal rib originates in the posterior portion of the scale and curves toward and the dome. Near the middle of the scale, a thick, rounded transversal rib connects the lateral parts of the submarginal rib. A secondary reticulum of smaller meshes with more delicate ribs may be developed under the transversal rib ( Fig. 1B ). There are parallel ribs radiating at right angles from the submarginal rib. The distal part of the scale is circumscribed by the thin raised structure formed by distal parts of the submarginal rib and the rounded transverse rib (pocket-like). Within this area, there is a dome and numerous (8-12) parallel curved ribs, sometimes anastomosed or interconnected by subtle lateral struts ( Fig. 1A ). The dome is broad and smooth, with no typical U-shaped structure. The curved ribs of the distal portion of the scale terminate near the dome ( Fig. 1C ).

Bristle was not observed. Stomatocyst unknown. Cell shape and dimensions unknown.

Figures

FIG. 1. — Body scales of Mallomonas teres, sp. nov.: A, B, scales observed in a transmission electron microscope; C, a scale observed in a scanning electron microscope. Scale bars: 1 µm.