Encyonopsis indonesica sp. nov. (Bacillariophyceae, Cymbellales), a new diatom from the ancient lake Matano (Sulawesi, Indonesia)

A new species, Encyonopsis indonesica, is described from the ancient lake Matano, Sulawesi island, Indonesia. The morphology of this species was studied by means of light and scanning electron microscopy. E. indonesica has a remarkable valve ultrastructure. The valve surface is ornamented with numerous longitudinal siliceous ribs and siliceous verrucae. Valve face delineated from the mantle by a thickened marginal ridge. Raised sterna border the raphe branches. Raphe is distinctly undulate with distal ends hooked strongly to the ventral side. The only similar species to E. indonesica is Amphora dissimilis described from New Caledonia. Comparison of both taxa is given and A. dissimilis is transferred to Encyonopsis. The taxonomic placement of both taxa is evaluated, and the phenomenon of external siliceous ornamentation is discussed. </div

Four new species from the diatom (Bacillariophyceae) genus Adlafia Moser, Lange-Bertalot & Metzeltin from waterbodies of Vietnam

Four species of the diatom genus were found from waterbodies of Vietnam and described as new to science. Their formal descriptions are presented herein and they are illustrated by light and scanning electron micrographs. These new species are: Glushch., Kulik. Kociolek, , Glushch., Kulik. Kociolek, , Glushch., Kulik. Kociolek, and Glushch., Kulik. Kociolek, These species are then compared to other similar taxa. Our new findings add to the number of species in this interesting genus and contribute to our understanding of the unique diatom flora found in Vietnam. Keywords: , diatoms, morphology, new species, Southeast Asia, Vietnam</p

Two new species of Navicula (Bacillariophyta) from Southeast Asia

We present light and scanning electron microscopical observations on two new species of Navicula Bory sensu stricto from Southeast Asia. Navicula winoniformis Chudaev, Glushchenko, Kulikovskiy &amp; Kociolek, sp. nov. differs from taxa with similar outline and size by the combination of simple drop-like external raphe endings deflected to the primary valve side, presence of well-developed external longitudinal grooves and relatively low lineolae density. Navicula sparsilineolata Chudaev, Glushchenko, Kulikovskiy &amp; Kociolek, sp. nov. can be discriminated from the taxa of similar valve shape and size by consistently lower lineolae density, and from the majority of them also by the structure of external proximal raphe endings with small projections in proximal parts and larger triangular insertions in distal parts. Some remarks on Navicula species diversity and its distribution in the Southeast Asia are given. &nbsp;</p

Molecular and Morphological Investigations of Two Giant Diatom Cymbella Species from the Transbaikal Area (Russia, Siberia) with Comments on Their Distributions

For the first time, a giant diatom species of the genus Cymbella from Lake Baikal was studied using molecular methods. Molecular and morphological investigations allowed to us to described one new species, Cymbella baicalaspera Glushchenko, Kulikovskiy and Kociolek sp. nov. This species is both morphologically similar and phylogenetically close to a second giant Cymbella species that we investigated here, identified by us as Cymbella himalaspera J&uuml;ttner and Van de Vijver in J&uuml;ttner et al. 2010. This species was first described from Nepal on the basis of a morphological investigation. Small morphological differences exist between the type population and specimens from Lake Baikal, but otherwise the two are identical. These very interesting results show that some Baikalian diatoms can be distributed more widely and are not only endemic to this ancient lake. Similarity between Cymbella baicalaspera sp. nov. and Cymbella himalaspera on the basis of both morphological features and their close phylogenetic relationships suggested by molecular data indicate they are sister species and an example of sympatric speciation. These results also suggest an early development of a species flock. This species group warrants additional research in terms of. their diversification and biogeography

Encyonopsis indonesica sp. nov. (Bacillariophyceae, Cymbellales), a new diatom from the ancient lake Matano (Sulawesi, Indonesia)

A new species, Encyonopsis indonesica, is described from the ancient lake Matano, Sulawesi island, Indonesia. The morphology of this species was studied by means of light and scanning electron microscopy. E. indonesica has a remarkable valve ultrastructure. The valve surface is ornamented with numerous longitudinal siliceous ribs and siliceous verrucae. Valve face delineated from the mantle by a thickened marginal ridge. Raised sterna border the raphe branches. Raphe is distinctly undulate with distal ends hooked strongly to the ventral side. The only similar species to E. indonesica is Amphora dissimilis described from New Caledonia. Comparison of both taxa is given and A. dissimilis is transferred to Encyonopsis. The taxonomic placement of both taxa is evaluated, and the phenomenon of external siliceous ornamentation is discussed

Planoplatessa gen. nov.&mdash;A New, Neglected Monoraphid Diatom Genus with a Cavum

A new monoraphid diatom genus, Planoplatessa gen. nov., is described on the basis of a detailed morphological investigation using light and scanning electron microscopy. We transferred Achnanthes joursacensis H&eacute;ribaud, a species described from fossil deposits in France, to our new genus. We investigated material from Mongolia from Recent populations. This taxon is known from fossils to Recent across the Holarctic. Achnanthes joursacensis was previously transferred to the genera Planothidium and Platessa, but the morphology of A. joursacensis does not share all morphological features with these two genera. We discuss important morphological features for the delimitation of monoraphid genera based on careful morphological and molecular investigations we presented previously. Planoplatessa gen. nov. as a genus is characterized by having uniseriate striae on both the raphe and the rapheless valves, a cavum in rapheless valves only, and straight distal raphe ends on the valve face

<i>Gandhia</i> gen. nov.—A New Diatom Genus with Unusual Morphology Split Off from the Genus <i>Navicula</i> Bory

A new naviculoid diatom genus, Gandhia gen. nov., was described based on a detailed morphological investigation using light and scanning electron microscopy. Gandhia obtecta (Jüttner and Cox) Kulikovskiy, Glushchenko, Iurmanov, M.Thacker, B.Karthick and Kociolek comb. nov. was previously described as a member of the genus Navicula Bory sensu lato. This species differs from other species in the genus Navicula s.l. by the presence of an internal siliceous lamina covering the alveoli and forming the image of longitudinal lines on either side of the axial area, visible in LM. The presence of this siliceous lamina is similar to laminae in genera such as Pinnularia and Gomphoneis. This unusual morphology is not typical for Navicula sensu stricto, as previously noted by other scientists. Additional investigation of Gandhia obtecta comb. nov. and Gandhia ramosissimoides (H.P. Gandhi) Kulikovskiy, Glushchenko, M.Thacker, B.Karthick and Kociolek comb. nov. from waterbodies of the Western Ghats and the Himalayan region was conducted. Comparison with other species with the same morphological features included two additional species in the genus, namely, Gandhia jakovljevicii (Hustedt) Kulikovskiy, Glushchenko, M.Thacker, B.Karthick, and Kociolek comb. nov. and Gandhia lucida (Pantocsek) Kulikovskiy, Glushchenko, M.Thacker, B.Karthick and Kociolek comb. nov. We discuss the biogeographic patterns of the species, including disjuncts between Europe and Asia

<i>Fragilaria shirshovii</i> sp. nov.—A New Species of Araphid Diatoms (Bacillariophyta, Fragilariophyceae) from the Gulf of Ob (Kara Sea, Arctic)

A new species, Fragilaria shirshovii sp. nov., is described on the basis of molecular and morphological investigations. Cells were isolated from the surface levels of desalinated water masses in the zone of mixing river and marine waters in the Gulf of Ob. The morphology of this species is analyzed with light microscopy (LM) and scanning electron microscopy (SEM). The valves of F. shirshovii sp. nov. are fusiform to almost linear. The frustules are linked together in the central part, forming double comb-shaped colonies. The axial area is narrow and linear, with a distinct rounded or rectangular fascia in the center. Ghost striae are present on the central area. Areolae are not discernible in LM. Apical pore fields are composed of small pores and closed papillary outgrowths. The lips of the rimoportula are well pronounced and the striae are uniseriate. Phylogenetic analysis based on partials 18S rRNA and rbcL genes infers the species F. shirshovii sp. nov. as a member of Fragilariaceae. The species most resembling F. shirshovii sp. nov. are F. crotonensis, F. pararumpens, F. bidens and F. perminuta. The differences between F. shirshovii sp. nov. and close taxa are discussed. This work is a pioneer investigation of Fragilariaceae taxa from the freshwater ecosystems of the Siberian Arctic using a combination of morphological and molecular tools

Molecular and Morphological Investigations of Two Giant Diatom <i>Cymbella</i> Species from the Transbaikal Area (Russia, Siberia) with Comments on Their Distributions

For the first time, a giant diatom species of the genus Cymbella from Lake Baikal was studied using molecular methods. Molecular and morphological investigations allowed to us to described one new species, Cymbella baicalaspera Glushchenko, Kulikovskiy and Kociolek sp. nov. This species is both morphologically similar and phylogenetically close to a second giant Cymbella species that we investigated here, identified by us as Cymbella himalaspera Jüttner and Van de Vijver in Jüttner et al. 2010. This species was first described from Nepal on the basis of a morphological investigation. Small morphological differences exist between the type population and specimens from Lake Baikal, but otherwise the two are identical. These very interesting results show that some Baikalian diatoms can be distributed more widely and are not only endemic to this ancient lake. Similarity between Cymbella baicalaspera sp. nov. and Cymbella himalaspera on the basis of both morphological features and their close phylogenetic relationships suggested by molecular data indicate they are sister species and an example of sympatric speciation. These results also suggest an early development of a species flock. This species group warrants additional research in terms of. their diversification and biogeography

New and Interesting Taxa from the Diatom Genus <i>Gomphonema</i> Ehrenberg in Shallow, Nearshore Sites on the Eastern Coast of Lake Baikal

During this investigation, sixteen species from the genus Gomphonema were found in a shallow bay (near Oimur, Kabansky District) located on the eastern shore of Lake Baikal. Eleven of these taxa have been described previously. Five species are described as new to science. We provide ecological information about these Gomphonema species, including their distribution within and outside Lake Baikal, and compare and contrast the new taxa with morphologically similar congeners. The diversity of morphologies present in Lake Baikal among the Gomphonema species suggests there has been both in-lake speciation as well as the introduction of various groups of species. The idea that Lake Baikal may support a high number of endemics by their partitioning niches based on depth is supported by the different groups of gomphonemoid diatoms present