Mallomonas alpestris, Kim & Lee, 2022

Kim, Han Soon & Lee, Jae Hak, 2022, Silica-scaled chrysophytes from Mt. Sinbul wetland in South Korea, Journal of Species Research 11 (4), pp. 253-265 : 259-263

Mallomonas alpestris sp. nov.

Han Soon Kim ( Figs. 21-24 )

Description. Its cells are small (4.5-5 × 9.5-11 μm), elongated ellipsoid with a broadly rounded posterior end and a distinctively protruding collar. There are three types of scales: domed collar scales; domeless body scales; and domeless rear scales with a short spine, and this has short apical bristles. Scales are arranged in transverse rows and each scale is overlapped by the scales positioned behind them in the same row and by the scales in the row above and below them ( Fig. 21 ). (i) 5-6 collar scales are asymmetric, small triangular shaped with a narrow dome bearing a distal pointed peak and a broadly rounded proximal end, and are covered with a more or less weakly developed reticulum of circular meshes. The submarginal ribs are ornamented with small papillae ( Fig. 22 ). (ii) Body scales are rhomboid, without a dome. The shield is marked with 6-10 remarkably stout transverse ribs and papillae of 2-4 longitudinal rows. The ribs get shorter from the middle towards the anterior and posterior ends of the shields. The arms of the V-rib are fused with anterior submarginal ribs forming continuous submarginal ribs with 3-5 rows of small papillae. The rows of papillae are reduced from the middle towards the anterior and posterior ends of the shields. The anterior flange has one row of papillae ( Fig. 24 , arrow). (iii) Domeless rear scales are in a small rhomboid shape, with a short stout conical spine. The structures of the shield and flanges are similar to those of body scales. The base plate of body and rear scales are perforated. Associated only with apical collar scales, bristles are short (3.8-4.5 μm long), approximately one-half or less of the cell length, slightly curved, smooth and slightly acutely tapered ( Figs. 21, 22 ).

Dimension. Cells 4.5-5 × 9.5-11 μm, Apical scales 1.8- 1.9 × 3-3.2 μm, Body scales 1.8-1.9 × 2.5-2.7 μm, Rear scales 1.4-1.5 × 1.6-1.7 μm, Bristles 3.8-4.5 μm long.

Type locality. Mt. Sinbul wetland, Sangbuk-myeon , Ulju County, Ulsan Megacity, South Korea (129°00.03′E, 35°25.32′N, sea level 745 m, pH 5.5-6.2, water temperature 0-9.1℃, EC 15.2-44.8 μS cm -1) .

Holotype. Fig. 21 (iconotypus) from materials collected on March 27, 2020 and deposited at the Herbarium of Kyungpook National University ( KNU), Daegu (KNUSBW2020 0327).

Isotype. Collection of specimens on SEM stub deposited at the Herbarium of KNU , Daegu, Korea, KNUSB200314 .

Etymology. The specific epithet “ alpestris ” refers to its occurrence in the subalpine region.

Figures

Figs. 21-24. Mallomonas alpestris sp. nov., 21. Whole cell with two needle shaped bristles, 22. Collar apical scales, 23. Body scales and rear scales with short stout spine, 24. Showing the shield with 9-10 transverse ribs and papillae of 3-4 rows and anterior flange with a row of papillae (arrow). Scale bars=21 (5μm), 22-24 (1μm).