Monactinus simplex var. echinulatum (Wittr.) Pérez, Maidana & Comas, 2009

Komarzewska, Katarzyna & Kowalski, Wojciech W. A., 2024, Staurastrum cyclacanthum var. pseudobrevissimus - a new variety of desmids and some other rare taxa found in peat bogs (Western Pomerania, Poland), Annales Universitatis Paedagogicae Cracoviensis Studia Naturae 9, pp. 9-32 : 16-17

¬ Monactinus simplex var. echinulatum (Wittr.) Pérez, Maidana & Comas, 2009 , Fig. 7H–K – Appendix 1

Basionym: Pediastrum simplex Meyen 1829 var. echinulatum Wittr. in Wittr. et Nordst. in 1883.

Synonym: Pediastrum clathratum (Schröder) Lemm. var. asperum Lemm. 1897, p. 182 , Fig. 6 .

Description: The variety occurs in the studied peat cut together with the typical form. Most often, very characteristic 4-cell cenobia were observed in the analysed material, less often 8-cell cenobia. Cenobia 4-celled with a small, regularly square central perforation, 8-celled, usually imperforated or with irregular perforation. The wall of the entire cell surface is covered with approximately 1 µm long spines. The processes of the marginal cells of the 4-cell cenobia are slightly arched. Cenobia 4 cells, 59.5–63.7 µm in diameter. Cells with processes 28.9–32.1 µm long, without processes 17.0–18.1 µm long and 13.6–14.5 µm wide. Marginal cell processes 11.9–12.3 µm long.

Cenobia 8 cells with a diameter of up to 81.6 µm. Marginal cells with processes 25.5– 32.3 µm long, 8.5–13.6 µm wide, without processes 13.6–20.4 µm long. Inner cells of cenobium with dimensions of 8.5×9.1–10.2×11.2 µm. The most common species in the research material are 4-cell cenobia. Multi-locular cenobia Monactinus simplex var. echinulatum (Wittr.) Pérez, Maidana & Comas , appear rarely. The research material also includes cenobia of the nominal species Monactinus simplex var. simplex . They are usually 8–16 multi-celled.

Found in site: In the plankton of the studied water reservoirs, Monactinus simplex var. echinulatum (Wittr.) Pérez, Maidana & Comas occurs with varying amounts throughout the entire research period from July to November. However, the optimal development of the taxon in individual peat cut is different. The variety has the most favorable conditions for development in peat cut waters No. 1 in July-September at a temperature of 21.8–26.8°C and a high pH value of 7.8–9.2.

Distribution in Poland: In Poland, Monactinus simplex var. echinulatum (Wittr.) Pérez, Maidana & Comas, 2009 (= Pediastrum simplex Meyen 1829 var. echinulatum Wittr. in Wittr. et Nordstedt 1883) is recorded relatively very rarely. So far, the taxon was reported from the plankton of a lake near Gdańsk ( Schröder, 1898), from a pond near Kraków ( Raciborski, 1889), from the area of Greater Poland, from warm-water lakes. Lake Gosławskie, Lake Licheńskie, Lake Pątnowskie, Lake Ślesińskie ( Socha, 1993), as well as lake Sumino in the Łęczycko-Włodawa Lake District (Pasztelaniec, Poniewozk, 2004). In a monographic study devoted to species of the genus Pediastrum Meyen , based on literature data and research ( Lenarczyk, 2014), she confirmed the occurrence of the taxon only in 10 sites out of 71 examined, located in various physiographic regions of Poland. In the research material, new sites were recorded in the area of the Southern Baltic Coast (2 sites), the southern Baltic Lake District (2 sites), the Polesie Lake District – 6 sites and the Northen Sub-Carpathia – 1 site.

General distribution and ecology: Monactinus simplex var. echinulatum (Wittr.) Pérez, Maidana & Comas (= Pediastrum simplex var. echinulatum ) is known from France, Israel, and Hungary. According to Lenarczyk (2014), the species prefers plankton of eurotrophic-mesotrophic waters. Research carried out ( Lenarczyk, 2014) on the basic hydrochemical and habitats indicate that the taxon prefers water with elevated temperature and alkaline reaction (pH 7.9–9.2), as well as conductivity 280–1588 µS/cm, total handiness 8.6–20.00, carbonate hardness 8.0–11.6, nitrates <5.0–10.0 mg/ dm 3 and Monactinus simplex var. echinulatum (Wittr.) Pérez, Maidana & Comas mixed catchments and on oxbow lake. It seems to be an important parameter determining the occurrence of Pediastrum simplex var. echinulatum namely the increased temperature of water and its strong alkaline reaction.

Figures

Fig. 7. A–K.A–B.Korshikoviella limnetica; C–G.Polyedriopsis spinulosa: various forms of cells; H–K.Monactinus simplex var.echinulatum (= Pediastrumsimplex var.echinulatum):H–J.four- and eight-cell cenobia, K. marginal cell of cenobium with pyrenoid (orig. engravings W. W.A. Kowalski)

Fig.6.Changes in the content of phosphates [P-PO4] and total phosphorus [Ptotal] during the research cycle in the water of the tested peat; peat cut: A – no. 1, B – no. 2, C – no. 3, D – no. 4, E – no. 5