FIGURES 55-58 - uploaded by Marina Potapova
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Surirella arctica, internal views, SEM. Fig. 55 Internal valve view. Fig. 56 Detail of irregularly arranged costae among rows of multiseriate striae. Fig. 57 Detail of the multiseriate striae with unoccluded areolae and the thick internal costae. Fig. 58 Valve apex showing striae with unoccluded areolae, costae and the end of the thickened median area. Scale bars = 1 µm.
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Surirella arctica comb. et stat. nov. (Bacillariophyta)—a rare arctic diatom Abstract Surirella terryi var. arctica has been described more than 50 years ago from northern Alaska. Since then, it has not been reported in the scientific literature except for a single record. We studied in detail the holotype slide and material of S. terryi var. arcti...
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Citations
... Surirella arctica is a rare Arctic species that had been recorded previously only from localities in the high Arctic (Patrick and Freese 1961, Antoniades et al. 2008, Veselá and Potapova 2014, Veselá 2017. This is the first record of this species south of 68°N latitude. ...
As a contribution to our knowledge of diatom biodiversity and biogeography in the United States, high resolution light microscope images are provided for 139 diatom taxa recorded from lake, stream, spring and glacier habitats in Wrangell-St. Elias National Park, Alaska. The spring had the highest taxa richness of the four habitats that were sampled, likely owing to the relative stability of this habitat compared to the others. Most of the taxa were described from northern and alpine locations in Europe and North America and are typical of habitats in the northern Rocky Mountains, with two notable exceptions. Surirellaarctica had been reported previously only from locations in the High Arctic of North America, north of 68°N latitude. Gomphonemacaperatum has a disjunct distribution in montane regions of the eastern and far western contiguous United States. This may be the first record of this taxon from Alaska.
... In the next 10 years, Lowe (1973) described two more species from Iowa: Surirella iowensis Lowe and S. stoermerii Lowe (Lowe 1973). Only one new species (Surirella lacrimula) has been recently added to this list from Virginia, the USA (Vesela & Potapova 2014). ...
Diatoms of the genus Surirella are considered to be a very diverse group, many of them are endemic species found in old lakes as well as in tropical regions worldwide. This study describes a new location of Surirella barrowcliffia. In 2005-2007, algological research on the taxonomic composition of benthic diatoms was conducted in the middle section of the Pilica River (Central Poland). A total of 23 benthic samples were collected from a single sampling site located in the town of Sulejów (159.8 km upriver). Altogether 242 diatom species were identified in the collected material. One of the most interesting taxa in this community was S. barrowcliffia. According to the information available in the world’s algological databases, such as Algaterra and AlgaeBase, S. barrowcliffia has so far been found only in England, France, Finland, northern Germany – in the Weser and the Kleine Wumme rivers, near Bremen, and in Romania in the Crapina-Jijila lake complex. S. barrowcliffia has not been recorded in the previous research conducted not only in the middle section of the Pilica River, but also in other Polish aquatic ecosystems.
... The most obvious examples of confusion are S. biseriata Brébisson, S. bifrons EHrenberg, S. linearis W. SmitH, and S. robusta EHrenberg. Some taxonomic problems have been recently addressed by re–examination, typification and/or description of new Surirella taxa, mainly from Otto Müllers' collection from East Africa (CoCquyt & JaHn 2005 CoCquyt et al. 2008), Gandhs' collection from India (KartHiCk 2009; KartHiCk et al. 2012), the Malili lakes in Indonesia (Bramburger et al. 2008 ) and several localities from North America (Veselá et al. 2013; veselá & potapova 2014). Recent molecular analyses further indicate that Suirella is a polyphyletic genus (RuCk & KoCiolek 2004) and additional studies of the morphological characters, as well as the ecological preferences of individual taxa, are required to resolve phylogenetic relationships within the genus. ...
Surirella is a polyphyletic and highly diverse diatom genus with more than 500 species described worldwide. Within a study of its diversity and distribution in the Republic of Macedonia, ancient Lake Prespa has been investigated, as " sister " to Lake Ohrid and part of a unique lake system with extraordinary age, biodiversity and number of endemic species. During the study, two new Surirella species have been identified and their LM and SEM based formal descriptions and differential diagnoses are provided herein. Surirella prespanensis sp. nov. has been observed in the contemporary and the fossil diatom flora of the lake. It can be distinguished from other similar taxa by its valve outline, size, shape of the median ridge and the presence of silica grooves along the raphe. Surirella hinziae sp. nov. is known only from the fossil diatom flora of Lake Prespa and can be recognized by its valve outline, size, shape of the median ridge and the presence of helictoglossa–like processes.
The morphological diversity in the genus Surirella is summarized, a new Surirella species is described, and the valve ultrastructure of S. undulata is documented under the scanning electron microscope. The new species, Surirella dongtingensis sp. nov., has a moderately twisted frustule with open valvocopula. Under the light microscope the frustule has one valve that is twisted at one apex, and the second valve is rotated 180 degrees compared to the first, such that one with the left side of one apex is not in the same focal plane with the three other sides, and the second is that the right side of one apex is not in the same focal plane with the three other sides. With respect to the valvocopula, the pars exterior bears oblique striae and scattered warts, and the pars interior have parallel striae and fimbriate ad-valve margins.
The morphological diversity in the genus Surirella is summarized, a new Surirella species is described, and the valve ultrastructure of S. undulata is documented under the scanning electron microscope. The new species, Surirella dongtingensis sp. nov., has a moderately twisted frustule with open valvocopula. Under the light microscope the frustule has one valve that is twisted at one apex, and the second valve is rotated 180 degrees compared to the first, such that one with the left side of one apex is not in the same focal plane with the three other sides, and the second is that the right side of one apex is not in the same focal plane with the three other sides. With respect to the valvocopula, the pars exterior bears oblique striae and scattered warts, and the pars interior have parallel striae and fimbriate ad-valve margins. Internally, both pars exterior and interior are smooth. Two nomenclatural changes for Cymatopleura aquastudia Kociolek & Q.You and C. xinjiangiana Q.You & Kociolek are provided to account for species to align with current concepts of the genus Surirella.
The morphological diversity in the genus Surirella is summarized, a new Surirella species is described, and the valve ultrastructure of S. undulata is documented under the scanning electron microscope. The new species, Surirella dongtingensis sp. nov., has a moderately twisted frustule with open valvocopula. Under the light microscope the frustule has one valve that is twisted at one apex, and the second valve is rotated 180 degrees compared to the first, such that one with the left side of one apex is not in the same focal plane with the three other sides, and the second is that the right side of one apex is not in the same focal plane with the three other sides. With respect to the valvocopula, the pars exterior bears oblique striae and scattered warts, and the pars interior have parallel striae and fimbriate ad-valve margins.
