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11On the morphology and taxonomy of Cyclotella rossii (Bacillariophyta)
S. I. Genkal
Institute for Biology of Inland Waters RAS, Borok, Yaroslavl Region, Russia Corresponding author. S. I. Genkal, genkal@ibiw.yaroslavl.ru
Abstract. An analysis of published data on Cyclotella rossii and С. chantaica has shown general morphological similarity and coincidence of the majority of quantitative and qualitative characters. They are valve diameter, frequency of marginal fultoportulae and number of satellite pores in them, number of central fultoportulae and number of their satellite pores, number of rimoportulae and valve relief, presence of externally colliculatelly, position of rimoportula and its fissure orientation respectively. Based on this data and priority the name С. chantaica, it is suggested to treat C. rossii as a synonym of С. chantaica and, considering the latest changes in their systematic position, expand the diagnosis of the species Pantocsekiella chantaica (Kuzmina et Genkal) K. T. Kiss, Genkal et Acs emend. Genkal.
Keywords: Bacillariophyta, Cyclotella rossii, Cyclotella chantaica, frustules morphology, taxonomy.
K морфологии и таксономии Cyclotella rossii (Bacillariophyta)
С. И. Генкал
Институт биологии внутренних вод им. И. Д. Папанина РАН, Борок, Ярославская обл., Россия Автор для переписки. С. И. Генкал, genkal@ibiw.yaroslavl.ru
Резюме. Анализ литературных данных показал общее морфологическое сходство и совпадение большинства количественных (диаметр створки, частота расположения краевых выростов и число опор у последних, число центральных выростов и число опор у них, число двугубых выростов ) и качественных (рельеф створки, наличие бугорчатости с наружной стороны,, расположение двугубого выроста и ориентация его щели) признаков Cyclotella rossii и С. chantaica. На основе этих данных и приоритета последнего названия предлагается свести C. rossii в синонимику к С. chantaica и, с учетом последних изменений в их систематическом положении, расширить диагноз вида Pantocsekiella chantaica (Kuzmina et Genkal) K. T. Kiss, Genkal et Acs emend. Genkal.
Ключевые слова: Bacillariophyta, Cyclotella rossii, Cyclotella chantaica, морфология панциря, таксономия.
The species Cyclotella rossii Hakansson was described using materials from a Swedish lake Laxa (Hakansson, 1990). The species belongs to small-sized forms (valve diameter 5-18 |im) and is characterized by 2-5 (rarely more) radial rows of puncta (Hakansson, 1990). Krammer, Lange-Bertalot (1991) gave a similar short diagnosis of this species. A detailed description of C. rossii with many light and electron microscopy micrographs was presented in a monograph by Houk et al. (2010). Other quantitative
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(number of striae in 10 jm, frequency of marginal fultoportulae and number of satellite pores in them, number of central fultoportulae and number of their satellite pores, number of rimoportulae) and qualitative (structure of alveoli, copula and central area) features were added to the diagnosis (Houk et al., 2010). Later, based on the study of numerous materials from lakes and rivers in the Republic of Karelia, the species diagnosis was refined (Genkal, Chekryzheva, 2016). Over the last few years, the systematic position of C. rossii has been repeatedly changed — at first, this species was transferred to the genus Lindavia (Schutt) De Toni et Forti as L. rossii (Hâkansson) Nakov, Gullo-ry, Julius, Theriot et Alverson (Nakov et al., 2015), then — to the genus Pantocsekiella K. T. Kiss et E. Acs as P. rossii (Hâkansson) K. T. Kiss et Âcs (Âcs et al, 2016). In 1989, based on materials from the Khantaika River, a new species was described — Cyclotella chantaica Kuzmina et Genkal. Morphologically this species is very similar to C. rossii (Genkal, Kuzmina, 1989). Later it was also transferred at first to the genus Lindavia (Nakov et al., 2015), and then — to Pantocsekiella (Âcs et al., 2016).
The aim of this publication is a comparative analysis of morphology of two above mention species with taxonomical resolutions.
As shown in Table, ranges of variability of quantitative features in P. rossii and P. chantaica coincide, except for the number of striae in 10 jm. Higher values of this characteristic can be associated with interpopulation variability — as the valve diameter decreases, the number of striae in 10 jm increases (Genkal, Popovskaya, 2004; Genkal, 2014; Genkal, Chekryzheva, 2016). C. chantaica valves are flat, externally col-liculate, mainly with several radial rows of punctae of unequal size ± shallow furrows or chaotically arranged, (Genlal, Kuzmina, 1989, figs 6-9), which is characteristic of C. rossii (Hâkansson, 1990, figs 47-49; Houk et al., 2010, pl. 207, figs 1-6, pl. 208, figs 1-6, pl. 209, figs 1, 2; Genkal, Chekryzheva, 2016, Figs 1-26). The rimoportula position and orientation in C. rossii varies to a large extent (Genkal, Chekryzheva, 2016, Figs 29-38). In C. chantaica the process occurs near alveoli and its fissure is oriented either at an angle or perpendicular to them (Genlal, Kuzmina, 1989, figs 11, 12), like in C. rossii. Auxospores are found in C. chantaica (Genlal, Kuzmina, 1989, figs 13, 14). In the first description of C. rossii (Hâkansson, 1990) and works by some researchers (Houk et al., 2010; Genkal, Chekryzheva, 2016), there is no information on coloniality of this species. According to the diagnosis (Genkal, Kuzmina, 1989), C. chantaica may occur as solitary cells as well as in colonies.
The stated above makes it possible to consider C. rossii to be conspecific with C. chan-taica and, consequently, a synonym of the latter, as well as refine its diagnosis. Considering the latest taxonomic changes, an extended diagnosis of this species is presented.
Pantocsekiella chantaica (Kuzmina et Genkal) K. T. Kiss, Genkal et Acs emend. Genkal = Cyclotella chantaica Kuzmina et Genkal, 1989, Biologia vnutrennikh vod. Infor-matsionnyy byulleten 4: 9. = Lindavia chantaica (Kuzmina et Genkal) Nakov, Gullory, Julius, Theriot et Alverson, 2015, Phytotaxa 217(3): 254. = Pantocsekiella chantaica (Kuzmina et Genkal) K. T. Kiss, Genkal et Acs, 2016, Fottea, Olomouc 16(1): 65.
Table
The variability of morphological features in Cyclotella rossii and C. chantaica according
to published data
Features Reference
Valve diameter, |im Number of striae in 1G |im Number of central fultoportulae Number of satellite pores in central furtoportulae Marginal fultoportulae arrangement Number of satellite pores in marginal fultoportulae Number of rimoportulae Number of radial rows of pucta in the central area
Cyclotella rossii
5-18 2-5, rarely more Hakansso, 199G
5-18 Krammer, Lange-Bertalot, 1991
9.5-16 14-16 2 On every 3-5 costae Genkal et al., 1997; Genkal, Yeshko, 1998
5-18 2-5, rarely more Hakansson, 2GG2
5-18 16-18 2-3(5) 2 On every 2-3(5) costae 2 1 2-8 Houk et al, 2G1G
5-31 12-25 1-13 2 (rarely 1 or 3) On every 2-8 costae 2 1 (rarely 2) 2-8 Genkal, Chekryzheva, 2G16
Cyclotella chantaica
3.421.8 18-35 1-5 2 On every 3-8 costae 2 1 Genkal, Kuzmina, 1989
= Cyclotella kuetzingiana var. radiosa Fricke in Schmidt 1900, Atlas der diatoma-ceenkunde 56: pl. 222, fig.8.
= Cyclotella rossii Hákansson, 1990, Diatom Research 5(2): 267. = Lindavia rossii (Hákansson) Nakov, Gullory, Julius, Theriot et Alverson, 2015, Phytotaxa 217(3): 258. = Pantocsekiella rossii (Hákansson) K. T. Kiss et Acs, 2016, Fottea, Olomouc 16(1): 68.
= Cyclotellapalustris Genkal et Kulikovskiy, 2008, Botanicheskii Zhurnal 93(5): 773. Cells cylindrical, 3.4-31 |im in diam., solitary or in colonies (4-41 cells). Striae of nearly equal lengths 12-35 in 10 |im. Marginal fultoportulae are situated on every, slighty depressed, 2-8 costae, Externally with a simple opening, internally with a short central tube surrounded laterally by two satellite pores. A single rimoportula (sometimes two) situated in the marginal area, external with a small opening on a shortened costa, internally with a sessile labium having a relatively wide radial, oblique or cir-cumferentially oriented slit. The central area in nearly flat, externally colliculate, more often with several radial rows of puncta of unequal size ± shallow furrows or chaotically, 1-13 fultoportulae situated eccentrically near the center or in the shape of ring, with a small, simple external opening, internally with short central tube surrounded by 2 (rarely 1-3) satellite pores. The girdle band is smooth, composed of several cop-ulae. There are auxospores.
Acknowledgements
This study was conducted in the framework of the Institutional research project "Systematics, diversity and phylogeny of aquatic autotrophic organisms in Russia and other regions of the world" (AAAA-A18-118012690095-4) and RFBR proj ect 19-04-00280_a.
References
Acs E., Ari E., Duleba M., Dressler M., Genkal S. I., Jako E., Rimet F., Ector L., Kiss K. T. 2016. Pantocsekiella, a new centric diatom genus based on morphological and genetic studies. Fottea, Olomouc 16(1): 56-78. https://doi.org/10.5507/fot.2015.028
Genkal S. I. 2014. Morphology, taxonomy, ecology and distribution of Cyclotella meduanae Germain
(Bacillariophyta). Nova Hedwigia. Beiheft 143: 127-140. Genkal S. I., Chekryzheva T. A. 2016. On the morphology, taxonomy, ecology and distribution of Cyclotella rossii Hakansson (Bacillariophyta). Nova Hedwigia 102(3-4): 399-421. https://doi.org/10.1127/nova_hedwigia/2015/0316
Genkal S. I, Kuzmina A. E. 1989. About new species of the genus Cyclotella Kutz. (Bacillariophyta).
Biologia vnutrennikh vod. Informatsionnyy byulleten 84: 9-11. (In Russ.). Genkal S. I., Popovskaya G. I. 2004. Morphological variability and taxonomy of the Baikal endemics from the genus Cyclotella Kutz. (Bacillariophyta). International Journal on Algae 6(2): 101-115. https://doi.org/10.1615/InterJAlgae.v6.i2.10
Hakansson H. 1990. A comparison of Cyclotella krammeri sp. nov. and C. schumannii Hakansson with similar species. Diatom Research 5(2): 261-271. https://doi.org/10.1080/0269249X.1990.9705118 Houk V, Klee R., Tanaka H. 2010. Atlas of freshwater centric diatoms with a brief key and descriptions. Part 3. Stephanodiscaceae. A. Cyclotella, Tertiarius, Discostella. Fottea 10 (Supplement): 1-498.
Krammer K., Lange-Bertalot H. 1991. Bacillariophyceae 3. Teil: Centrales, Fragilariaceae, Eunotia-ceae. Susswasserflora von Mitteleuropa. Bd. 2/3. Stuttgart, Jena: 576 S.
Nakov T., Gullory W. X., Theriot E. C., Alverson A. J. 2015. Towards a phylogenetic classification of species belonging to the diatom genus Cyclotella (Bacillariophyceae): Transfer of species formerly placed in Puncticulata, Handmannia, Pliocaenicus and Cyclotella to the genus Lindavia. Phytotaxa 217(3): 249-264. https://doi.org/10.11646/phytotaxa.217.3.2
Литература
Acs É., Ari E., Duleba M., Dressler M., Genkal S. I., Jako É., Rimet F., Ector L., Kiss K. T. 2016. Pantocsekiella, a new centric diatom genus based on morphological and genetic studies. Fottea, Olomouc 16(1): 56-78. https://doi.org/10.5507/fot.2015.028
Genkal S. I. 2014. Morphology, taxonomy, ecology and distribution of Cyclotella meduanae Germain (Bacillariophyta). Nova Hedwigia. Beiheft 143: 127-140.
Genkal S. I., Chekryzheva T. A. 2016. On the morphology, taxonomy, ecology and distribution of Cyclotella rossii Hakansson (Bacillariophyta). Nova Hedwigia 102(3-4): 399-421. https://doi.org/10.1127/nova_hedwigia/2015/0316
[Genkal, Kuzmina] Генкал С. И., Кузьмина А. Е. 1989. О новом виде из рода Cyclotella Kütz. (Bacillariophyta). Биология внутренних вод. Информационный бюллетень 84: 9-11.
Genkal S. I., Popovskaya G. I. 2004. Morphological variability and taxonomy of the Baikal endemics from the genus Cyclotella Kütz. (Bacillariophyta). International Journal on Algae 6(2): 101-115. https://doi.org/10.1615/InterJAlgae.v6.i2.10
Hakansson H. 1990. A comparison of Cyclotella krammeri sp. nov. and C. schumannii Hakansson with similar species. Diatom Research 5(2): 261-271. https://doi.org/10.1080/0269249X.1990.9705118
Houk V, Klee R., Tanaka H. 2010. Atlas of freshwater centric diatoms with a brief key and descriptions. Part 3. Stephanodiscaceae. A. Cyclotella, Tertiarius, Discostella. Fottea 10 (Supplement): 1-498.
Krammer K., Lange-Bertalot H. 1991. Bacillariophyceae 3. Teil: Centrales, Fragilariaceae, Eunotia-ceae. Susswasserflora von Mitteleuropa. Bd. 2/3. Stuttgart, Jena: 576 S.
Nakov T., Gullory W. X., Theriot E. C., Alverson A. J. 2015. Towards a phylogenetic classification of species belonging to the diatom genus Cyclotella (Bacillariophyceae): Transfer of species formerly placed in Puncticulata, Handmannia, Pliocaenicus and Cyclotella to the genus Lindavia. Phytotaxa 217(3): 249-264. https://doi.org/10.11646/phytotaxa.217.3.2
