Maxim Kulikovskiy

New species of Eunotia (Bacillariophyta) from Lake Baikal with comments on morphology and biogeography of the genus

Abstract: In this article, we describe four species of Eunotia new to science from Lake Baikal based on light and scanning electron microscopic examination of valve morphology. Unlike most other species of the genus, all of the newly described species possess widely spaced transapical striae, a feature unique for Eunotia. Amongst the characters upon which we distinguish the new species from Lake Baikal are size ranges, raphe structure and position, stria density and the presence/absence of rimoportulae. Only a few established taxa, such as E. minor, E. submonodon and E. incisa, show weak morphological similarities to the newly described species. Hence, phylogenetic relationships are difficult to assess. All new species are described from recent samples; these are E. dorsicrenata sp. nov., E. leptocrenata sp. nov., E. pseudincisa sp. nov. and E. immanis sp. nov. One of the new taxa (E. dorsicrenata) occurs in the geological record dated to c. 7.7 million years ago. For the other species, information of their distribution in the geological record is missing. However, none of the species described in this article were observed outside of Lake Baikal, even in lakes occurring in the Baikal rift zone. These species are found in a deeper part of the lake, adding support to the notion of the immiscibility of Baikals flora and fauna. We also discuss the idea of species flocks in diatoms and whether this group of species of Eunotia may represent a species flock in Lake Baikal.

Taxonomy and geographical distribution of the diatom genus Epithemia Kützing in water bodies of Central Asia

The morphology of the diatom genus Epithemia from ecosystems of Central Asia (Russia and Mongolia) is studied. It is shown that in the studied ecosystems there are species with local or endemic distribution, like in Lake Baikal, and taxa known from the Holarctic. Original morphological descriptions and pictures of 13 taxa are given. Three new taxa are described. They are E. compacta Kulikovskiy & Lange-Bertalot sp. nov. from Lake Baikal; E. selengaensis Vishnjakov, Kulikovskiy & Genkal sp. nov. from the Selenga River; and E. perlongicornis Vishnjakov, Kulikovskiy & Genkal sp. nov. from water bodies of the Great Lakes Depression in Mongolia.

DIATOM FLORA OF POLISTOVO-LOWATSKI SPHAGNUM TRACT (EUROPEAN RUSSIA). I. EOLIMNA CHISTIAKOVAE SP. NOV. AND FURTHER TRANSFERS TO THE GENUS EOLIMNA LANGE-BERTALOT & SCHILLER

The present paper focuses on diatom taxa inhabiting one of the largest wetland areas of Europe, the Polistovo-Lowatski Sphagnum tract in the European part of Russia. The samples collected in this area revealed numerous rare and new species. Only one is described here as new to science, Eolimna chistiakovae, an apparently acidobiontic, oligotraphentic taxon. Furthermore, nine taxa are transferred from Navicula Bory or Naviculadicta Lange-Bertalot to Eolimna; E. elorantana, E. vekhovii, E. raederae, E. jurafontinalis, E. schaumburgii, E. rotunda, E. submuralis, E. muraloides, and E. utermoehlii based on data from literature. It is also shown that Navicula heufleriana var. septentrionalis Hustedt 1924 sensu Simonsen 1987 conforms to Naviculadicta elorantana Lange-Bertalot and has to be merged in synonymy having no priority at species rank. The characters of the genus Eolimna are discussed in comparison with other genera split from Navicula sensu lato.

Are there species flocks in freshwater diatoms? A review of past reports and a look to the future

We review the literature on species flocks in diatoms. Past descriptions of species flocks in diatoms are of few species and do not demonstrate monophyly of the taxa explicitly. The genus Tetralunata, with 19 taxa described from Lake Toba, Indonesia, may be the best example to date of species flocks in freshwater diatoms. Other examples for this group are evaluated, from ancient lakes, river drainages and islands, to more geologically short-lived areas and habitats. Other examples may reside in the Rift Valley lakes of East Africa, Amazonia, lakes Baikal, and Ohrid, and some islands such as New Caledonia, Sulawesi, and Madagascar. It would appear that the phenomenon is not expressed in Hawaii, which has endemic, but very few, species. It is interesting to note that nearly all of the examples of species flocks of extant diatoms are of those groups that possess a raphe system. The role of molecular studies to study species flocks is discussed. Other features not traditionally examined to recognize species-level distinctions (physiology, ecology) which may be useful in the future to help identify species flocks in freshwater diatoms.

Morphology, taxonomical position, and distribution of the genera of diatoms Ochigma and Khursevichia from Lake Baikal

The morphology of the genera of diatoms Ochigma and Khursevichia based on new data from LM and SEM is discussed. The genera have been described from Lake Baikal. The morphology of raphe and pore occlusions resembles those in cymbelloid diatoms. We suggest including these genera in the order Cymbellales and the family Cymbellaceae. The role of different morphological features that are important for the taxonomy is discussed. Symmetry plays a minor role in diatom taxonomy. The morphology of raphe and pore occlusions is the most important factor. Pore occlusions within the genus Khursevichia belong to the tectulum type. Pore occlusions within the genus Ochigma are more complicated: they are represented by a tectulum inside and a foricula outside. The broadened description of the species Ochigma dubiosa is given.

Molecular phylogeny of monoraphid diatoms and raphe significance in evolution and taxonomy

The phylogenetic position of the genera Rossithidium and Psammothidium was studied using the plastid gene rbcL. The genus Rossithidium is not an independent taxon and should be transferred to Psammothidium. Taxa from Psammothidium genus formed a sister, but independent clade to taxa with Achnanthidium. Our data has shown that the order Achnathales was not the natural taxon and should be reduced, but the three families included in it were natural. Genera like Psammothidium (including Rossithidium) and Lemnicola should be included into the family Achnanthidiaceae. Therefore, raphe does not play an important role in diatom taxonomy and its loss occurred many times during the evolution of diatoms.

Typification, valve ultrastructure, and systematic position of Gomphonema gomphopleuroides Amossé ex Kociolek, Glushchenko and Kulikovskiy, an endemic diatom from Southeast Asia

Light and scanning electron microscope observations are presented on the diatom Gomphonema gomphopleuroides. This astigmate species, described originally from Vietnam, is large and robust, and has raphe branches that are shorter than in most other freshwater gomphonemoid diatoms. The uniseriate striae are unoccluded and the areolae are bordered by lunate ridges on one side, another unique feature of the species. Internally there is an apically elongated central nodule. This species is contrasted with the genus Gomphopleura, which also has shortened raphe branches. Gomphonema gomphopleuroides appears morphologically most similar to G. kaznakowi, a species endemic to southern China. The name G. gomphopleuroides is validated here with the designation of a neotype.

Morphology, ecology and distribution of the diatom (Bacillariophyceae) species Simonsenia delognei (Grunow) Lange-Bertalot

Simonsenia delognei is a diatom species which is relatively rarely recorded, but apparently widespread in Europe and other continents. This taxon has recently been discovered for the first time in springs of Central Poland, where it was found to occur abundantly. Somewhat later this species has also been identified and photographed in samples from the Eagean Region in Turkey. Light and electron microscopic studies were carried out on S. delognei populations from the Quaternary spring located near Łódź (Central Poland) and from the Porsuk and Felent Rivers and a spring in the Türkmen Mountains in Kütahya and Havuzdere Stream in Yalova (NW Turkey). Morphological studies were accompanied by environmental measurements and determination of changes in the seasonal distribution of S. delognei in a key area, i.e. the Porzeczkowe spring in Central Poland, which are included in the present study. Identification of S. delognei under a light microscope is difficult and hence an electron microscope is required for accurate taxonomic identification.

Taxonomy and distribution of the genus Eunotia Ehrenberg in aquatic ecosystems of Vietnam

Taxonomy and geographical distribution of diatom taxa from the genus Eunotia are discussed. Fourteen Eunotia species are found in aquatic ecosystems of Central and South-Eastern Vietnam: E. indosinica, E. karveerensis, E. sulcata, E. cf. vumbae, E. novaecaledonica, E. naegelii, E. paramuscicola, E. rabenhorstii, E. tropica, E. sioliopsis, E. australominor, E. mucophila. Two species which are new for science are described Eunotia skvortzovii Glushchenko & Kulikovskiy sp. nov. and Eunotia fogedii Glushchenko & Kulikovskiy sp. nov. Eunotia sulcata Hustedt ex Glushchenko & Kulikovskiy is validated. The species are illustrated by original LM and SEM microphotographs. The main qualitative and quantitative taxonomic data are given. The distribution is found species is discussed.

Amphipleura vavilovii: A new diatom species of the family Amphipleuraceae from Laos

A new diatom species Amphipleura vavilovii sp.nov. is described from water ecosystems of South-Eastern Asia (unnamed river flowing into ecological village Namlik, Laos). Species is illustrated by original LM and SEM microphotographs. Description is given on the basis LM and SEM data.