Readers of this Beiheft of Nova Hedwigia will find articles on a large variety of diatoms, from fossil to recent, marine to freshwater, established species and genera to new ones. Fifty-two authors have contributed to this volume by their diversity of interests. Topics range from morphology, taxonomy, ecology and distribution of diatoms found all over the world (from Europe to Russia and Asia, from the entire American Continent and even the Antarctica) and from past to recent.

The variety of the papers presented in this volume reflects the diversity of scientific interests of Nina Strelnikova, to whom this Beiheft is dedicated.

This volume is of interest for every scientist working on diatoms and interested in the variety of diatom research. It should not be missing in any library.

Professor Nina Ivanovna Strelnikova is the leader of diatom research in Russia. Her researches focus on primarily Cretaceous and Palaeogene diatoms. Her unique collections provided excellent basis for studying diatom evolution. She described 11 diatom genera and 63 species new for science and established 63 new combinations. She is the main force behind the book series “Diatoms of Russia and adjacent countries”. Beside research, she is an erudite professor, mentor of many Russian diatomists and organiser of diatom conferences called “Diatom Schools”.
This volume is dedicated to Professor Strelnikova on the occasion of her 80th birthday. One of her former students, Professor Marina Potapova provides a thoughtful and exhaustive overview of life story of the remarkable scientist in the introduction entitled “Eighty years of life” that is supplemented with photographs. At the end of the introduction of Nina Strelnikova’s publications, the new genera and species described by her, as well as the three genera and nine species named after her honour (some of these patrionyms are referred to this volume) are listed.
The introduction is followed by twenty-seven papers. The variety of subjects reflects the diversity of Nina Strelnikova’s scientific interest including research on fossil and recent diatoms.
Fossil diatoms are presented from several sites ranging from New Mexico (United States) to Central Russia, Transuralia and adjacent regions, from Gulf of Gdańsk (Southern Baltic Sea) to Prince Charles Mountains (East Antarctica). The oldest material is from 56 million years old Palaeocene-Eocene Thermal Maximum. In these studies, fossil assemblages were used for constructing biostratigraphic zonation, reconstructing palaeo-environmental changes and tracking diatom evolution. Besides two new genera (the Strelnikoviella in the centric Stephanodiscaceae family and Saeptifera in the araphid Tabellariaceae family) and seven new species (in the genera Cyclotella, Strelnikoviella and Saeptifera) are described from fossil materials. Gladenkov analysed the geographic distribution of some fossil marine planktonic diatoms typical of the early Oligocene and found a southward then a northward route of migration. He discusses the potential mechanisms for their dispersal. Buczkó et al. studied the structure and silicification of Navicula haueri reinvestigating Miocene material from the Carpathian Realm by means of light, and for the first time scanning electron microscopy. The authors also provide the biostratigraphy and distribution of the characteristic Neogene freshwater diatom.
Recent diatoms including planktonic and benthic, freshwater and marine taxa are reported from various habitats ranging from mesotrophic lakes in Maine and Vermont (United States), as well as tundra ponds and streams of the Bering Island (Kamchatka) through the Black Sea and mountainous ephemeral rock-ponds in Algeria to tropical reservoirs and coastal waters of Vietnam and South American saline lakes. From these waters a new genus (the biraphid Ninastrelnikovia), nineteen new species (in the genera Diadesmis, Eunotia, Pinnularia, Psammothidium, Urosolenia, Platessa, Craticula, Gomphonema, Navicula and Caloneis) and two new combinations (in the genera Ninastrelnikovia and Placoneis) have been described.
Several authors performed morphological investigations in order to clarify the taxonomy of previously established taxa including Hantzschia amphioxys, Cyclotella meduanae, Aulacoseira gessneri, Hemiaulus giganteus, Gomphonema delicatulum and G. firmum, the species complexes of Placoneis clementis and Paraplaconeis placentula. The analysis of the latter complexes resulted in description of four new species.
Morphometric methods are used in diatom research in quantifying differences and separation of taxonomic groups. Pappas et al. review these tools including theoretical background, chronological history and importance of their application in diatom research, as well as the connections between the morphometric methods and biologically meaningful results. The authors provide a detailed description of the outline shape analysis that is the most frequently used method.
Ecology can be important for distinguishing taxa, ecological preferences can indicate cryptic species. However, some taxa have wider tolerance range than originally considered, as Stachura-Suchoples and Kulikovskiy demonstrated. They showed the freshwater tolerance of Conticribra weissflogii that was previously considered as a marine and brackish-water diatom.
Overall, this book contains useful information on diatoms on wide spatial and temporal scale. The studied organisms are illustrated on detailed, good quality light and/or scanning electron microscopic photographs. This volume can be useful to everyone investigating diatoms being recent or fossil, freshwater or marine, benthic or planktonic.

M. Duleba

Acta Botanica Hungarica 57, 2015