Newly recorded and rare Desmidiales ( Charophyta : Conjugatophyceae ) from the Middle Urals , Russia

New disributional data on 14 previously unrecorded or rare species and varieties of algae belonging to Closteriaceae, Desmidiaceae, Gonatozygaceae and Peniaceae (order Desmidiales) are presented for the Middle Urals. Closterium cornu Ehrenberg ex Ralfs, Closterium macilentum Brébisson, Closterium navicula (Brébisson) Lütkemüller, and Cosmarium crenulatum Nägeli are newly recorded to the Urals. A brief description, including measurements of cells as well as regional and global distribution, is given for each taxon.

Since the 1920s, research into the algal flora of the Urals has accumulated a substantial body of data on the bio diversity of various groups of algae, including Conjugatophyceae.The most thorough studies were carried out in the Polar, Subpolar, and the Southern Urals (Voronikhin 1930;Snitko and Sergeeva 2003;Yarushina et al. 2004;Patova and Demina 2008;Sterlyagova 2008;Snitko 2009).In the present paper, new records of Desimidiales are presented and expand sparsely available data (Yarushina et al. 2003;Butakova and Stanislavskaya 2004;Belyaeva and Pozdeev 2005;Shakhmatov 2014Shakhmatov , 2015) ) on distribution of conjugates in the Middle Urals.
The samples were studied under a light microscope (Levenhuk 320).Species were identified using keys on Conjugatophyceae (Kossinskaya 1952(Kossinskaya , 1960;;Palamar-Mordvintseva 1982;Coesel and Meesters 2007) and verified by Dr. A. F. Luknitskaya (V.L. Komarov Botanical Institute of the Russian Academy of Sciences).Validity of taxa and general distribution were checked in AlgaeBase (Guiry and Guiry 2016).Photographs of algae were taken with a Levenhuk C310 NG digital camera.The photos were deposited in the herbarium of the Ural Federal University (UFU A 91 to 112).
One rare and 13 previously unrecorded species or varieties of Desmidiales were identified from the Middle Urals in the present study.They belong to Closteriaceae (4), Desmidiaceae (8), Gonatozygaceae (1), and Peniaceae (1) (order Desmidiales).Four species are newly recoreded to the Urals in general.A list of species with brief description of the taxa, as well as their distribution in the Urals and globally, is given below.

Closterium navicula (Brébisson) Lütkemüller, 1905
Figure 5 A single record in the Cherkaskul lake (UFU A 106).Cells straight, fusiform, 70.3 μm long and 15.9 μm wide.Ends widely rounded, apical vacuoles contain one large crystal of gypsum.The species is newly recorded from the Urals.
The species is found in a small number in the Bolshoye Yamskoye (UFU A 94) and Cherkaskul (UFU A 107) lakes.Cells are oval in general outline, 24.9-32.3μm long and 18.4-23.8μm wide.Semicells with smooth, undulating cell wall.Sinus narrow-linear, isthmus 6.2-6.6 μm wide.The species is new to the Urals.
Distribution: Europe, Asia, Australia, New Zealand, South America.Distribution: Europe, Asia, Africa, Australia, North America, South America.

Closterium cornu Ehrenberg ex Ralfs, 1848
Figure 3 The species is found in small quantities in the Travyanoye lake (UFU A 101).Cells fusiform, almost straight or slightly curved, 148.3-155.4μm long and 9.2-9.5 μm wide.Ends obtuse, apical vacuoles contain one large crystal of gypsum each.The species is newly recorded from the Urals.

Closterium macilentum Brébisson, 1856
Figure 4 The species is found in a small number in the Travyanoye (UFU A 102) and Cherkaskul (UFU A 108) lakes.Cells fusiform, straight, slightly curved at the ends, 186.9-258.9μm long and 8.7-11.7 μm wide.The species can be confused with Closterium cornu Ehrenberg ex Ralfs, from which it differs by a larger size, a frequent formation of girdle bands, as well as the presence of few small crystals of gypsum in the apical vacuoles.The species is newly recorded from the Urals.Cosmarium granatum Brébisson ex Ralfs, 1848 Figure 7 The species is found in a large number in the the Bolshoye Yamskoye (UFU A 95) and Cherkaskul (UFU A 96, 110) lakes.Cells rhomboid in general outline, 36.8-42.5 μm long and 24.2-29.4μm wide.Cell wall punctured.Sinus narrow-linear, isthmus 6.1-9.7 μm wide.The species has been known from the South (Snitko and Sergeeva 2003;Yarushina et al 2004), Subpolar (Sterlyagova 2008), Polar (Patova and Demina 2008) Urals and from the western foothills of the Middle Urals (Belyaeva 2004).
Distribution: Europe, Asia, Australia, New Zealand, North America, South America.
The species is found in a small number in the Karaguz (UFU A 103), Travyanoye (UFU A 104) and Cherkaskul (UFU A 92) lakes.Cells are octagonal in general outline, 18.1-22.2μm long and 17.4-20.2μm wide.Semicells trapezoidal with concave sides and slightly undulate flat tops.Cell wall smooth.Sinus narrow-linear, isthmus 4.4-6.7 μm wide.The species has been previously known from the Southern Urals (Snitko and Sergeeva 2003;Yarushina et al 2004).
Distribution: Europe, Asia, Australia, North America, South America.
Distribution: Arctic, Europe, Asia, Australia, New Zealand, North America, South America.
A single record in the Cherkaskul lake (UFU A 91).Cells oval in general outline, 132.6 μm long and 68.5 μm wide.Sinus wide open, shallow, isthmus of 55.3 μm wide.Cell wall covered by large granules, placed in diagonal rows.This is a very rare species, previously known in the Middle Urals only from the Boevskoye lake (Shakhmatov 2015).

Gonatozygon brebissonii De Bary, 1858
Figure 11 A single record in the Cherkaskul lake (UFU A 97).Cells cylindrical, elongated, 114 μm long and 5.5 μm wide.Ends truncate, capitate.Cell wall covered by small spines.The species was previously known from the Southern Urals (Yarushina et al 2004).
Distribution: Arctic, Europe, Asia, Australia, New Zealand, North America, South America.

Penium polymorphum (Perty) Perty, 1852
Figure 12 A single record in the Cherkaskul lake (UFU A 98).Cells elliptical with a slight constriction, 40.5 μm long and 17.5 μm wide.Cell wall covered by thin strokes.The species has been previously known from the Polar Urals (Voronikhin 1930).
Distribution: Europe, Asia, Australia, New Zealand, North America, South America.

Staurastrum bicorne Hauptfleisch, 1888
Figure 13 A single record in the Cherkaskul lake (UFU A 111).Cells 60.1 μm long and 47.3 μm wide without processes (with processes 82.2 μm wide), isthmus 13.9 μm wide.Semicells cup-shaped, fusiform when viewed from the top.The upper angles of cells extend into the hollow parallel processes with two spines at the ends.Cell wall on the top is covered by short spines and denticles.The species has been previously known from the Southern Urals (Snitko and Sergeeva 2003;Yarushina et al. 2004).
Distribution: Europe, Asia, Australia, New Zealand, North America.

Staurastrum lunatum Ralfs, 1848
Figure 14 The species is found in a small number in the Cherkaskul lake (UFU A 112).Cells 27.6-30.4μm long and 32.6-32.8μm wide, isthmus 13.5-13.7 μm wide.Semicells cup-shaped, triradiate when viewed from the top.The upper angles extended in diverging processes with one short spine on end.Cell wall is covered by small inconspicuous granules, arranged in concentric rows around angles.The species has been previously known from the Southern Urals (Snitko and Sergeeva 2003;Yarushina et al. 2004).
Distribution: Europe, Asia, Australia, North America, South America.

Staurastrum paradoxum Meyen ex Ralfs, 1848
Figure 15 The species is found in a small number in the Bolshoye Yamskoe lake (UFU A 99).Cells 15.5 μm long and 11.9 μm wide without processes (with processes 82.2 μm wide), isthmus 13.45 μm wide.Semicells cup-shaped, triradiate when viewed from the top.The upper angles elongate in diverging processes with three spines at the ends.Cell wall smooth.The species has been previously known from the Southern Urals (Snitko and Sergeeva 2003;Yarushina et al. 2004) and Polar (Sterlyagova 2008) Urals.

Figure 1 .
Figure 1.Location of research area (B) in the Ural Mountains (A).