Euastrum kossinskiae Anissimova et Philippov, 2018

Anissimova, Olga V. & Philippov, Dmitriy A., 2018, Euastrum kossinskiae: a new species of desmid from the aapa mire of the Vologda Region (European Russia), Phytotaxa 376 (1), pp. 77-80 : 77-79

Euastrum kossinskiae Anissimova et Philippov , sp. nov. ( Figs. 1–10).

Diagnosis: —Cells in frontal view slightly longer than broad, with a deep linear sinus. Semicells rectangular or back-trapeziform with concave sides. Apices truncate with a shallow apical incision. Apical and basal angles broadly rounded. Lobes not visible. Semicell whith a broad central inflation. Cells in apical view elliptic with shallow inflation. Cell wall scrobiculated around slight inflation in the semicell centre. Semicells in side view oval with shallow inflation. Chloroplast with a single pyrenoid. Dimensions: length 14–15 μm, breadth 11.4–12.0 μm, isthmus 3–4 μm, thickness 9–10 μm.

Type:— RUSSIA, Vologda Region, Vytegra district: Piyavochnoe Mire, 60°46′57.0″ N, 36°50′38.5″ E, of epiphyton, D. Philippov, 15 September 2015, (holotype: MW!, preserved as a fixed natural sample, depicted in Fig. 1, Algae collection of the Department of Mycology and Algology).

Etymology:—The species is dedicated to Russian desmidiologist Ekaterina Konstantinovna Kossinskaya (1900–1957), who has intensively studied different aspects of the desmids for many years.

Distribution and ecology:—The taxon is known only from Piyavochnoe Mire. It was found in samples of epiphyton in 2015 and 2016. Studied samples had pH values of 6.3–6.6, the salinity of 10.5–12.0 mg/l. In the flark cenoses, 28 species of higher plants were found, among which sedges ( Rhynchospora alba (L.) Vahl, Carex lasiocarpa Ehrh. , C. chordorrhiza Ehrh. ), herbs ( Menyanthes trifoliata L., Scheuchzeria palustris L., Utricularia intermedia Hayne ), and hypnum mosses ( Scorpidium scorpioides (Hedw.) Limpr. ) were dominant. The samples contained large numbers of desmids (more than 80 species in total). There were 12 species of Euastrum . Actinotaenium crassiusculum (De Bary) Teiling, A. cucurbita (Brébisson ex Ralfs) Teiling, Euastrum crassum Ralfs , E. humerosum Ralfs , Spondylosium lundellii Borge , Staurastrum aculeatum Meneghini ex Ralfs were dominated.