Biological Communications <p>Biological Communications is a rebranded new title of the former journal «Vestnik of Saint Petersburg University. Series 3. Biology». The journal was founded as «Vestnik of Leningrad University» in 1946.&nbsp;Since 1953, it was published under several series. In 1956 the series «Biology» was first established.&nbsp;As its predecessors, Biological Communications is published at a quarterly&nbsp;basis.</p> Saint Petersburg State University en-US Biological Communications 2542-2154 <p>Articles of <em>Biological Communications</em> are open access distributed under the terms of the <a title="License Agreement" href="/about/submissions#LicenseAgreement" target="_blank" rel="noopener">License Agreement</a> with Saint Petersburg State University, which permits to the authors unrestricted distribution and self-archiving free of charge.</p> The oldest titanosaurian sauropod of the Northern Hemisphere <p><em>Volgatitan simbirskiensis</em>, gen. et sp. nov., is described based on a series of anterior and middle caudal vertebrae from a single individual discovered in the Lower Cretaceous (upper Hauterivian, Speetoniceras versicolor ammonite Zone) marine deposits at Slantsevy Rudnik vertebrate locality near Ulyanovsk City, Russia. The new taxon is characterized by strongly procoelous anterior and middle caudal vertebrae, a long centrum of the first caudal vertebra, a strong ventral ridge in the anterior and middle caudal vertebrae, a neural arch positioned at the anterior half of the centrum, hyposphene-hypantrum articulation in the anterior caudal vertebrae, and somphospondylous bone texture. Phylogenetic analysis places the new taxon as a lithostrotian titanosaur, a basal member of the lineage leading to the Lognkosauria. This lineage previously contained only South American taxa with body mass reaching 60–70 tons. <em>Volgatitan</em> gen. nov. is the first European and the geologically oldest representative of this lineage. Its body mass is estimated as 17.3 tons. Discovery of <em>Volgatitan</em> gen. nov. suggests that the lithostrotian lineage leading to the Lognkosauria had a wider distribution in the Early Cretaceous and became extinct everywhere except South America by the end of the Early Cretaceous.</p> Alexander Averianov Vladimir Efimov ##submission.copyrightStatement## 2018-11-30 2018-11-30 63 3 145–162 145–162 10.21638/spbu03.2018.301 Strontium dynamics in soil and assimilation by plants during dissolution of conversion chalk <p>In an experiment carried out on Soddy-podzolic soil, limed with conversion chalk in a wide range of doses, the rate of dissolution of strontium-containing chalk and its effect on soil and plant were studied. Here we show that the complete decomposition of chalk applied to soil is achieved in the 3–4 years after its application. Increase in the concentration of plant available strontium in soil lasts until the chalk is completely dissolved. The dose of applied chalk determined the assimilation of strontium by rapeseed plants. We have found differences in accumulation of strontium by rapeseed in the year of application of chalk and in the third and fourth year of its aftereffect. We conclude that chalkmeliorated soil will generate strontium streams into plants for a longer period. We further propose empirical models that adequately describe: a) the processes of chalk dissolution in the soil; b) the dynamics of the content of strontium compounds accessible to plants in the process of interaction between chalk and soil; c) strontium accumulation in vegetative mass of rapeseed at different stages of chalk dissolution.</p> Anton Lavrishchev Andrey Litvinovich Vladimir Bure Olga Pavlova Elmira Saljnikov ##submission.copyrightStatement## 2018-11-30 2018-11-30 63 3 163–173 163–173 10.21638/spbu03.2018.302 Homoarginine and ornithine production during C2C12 myogenic differentiation <p>Assessment of cellular rates of amino acid consumption and release in vitro allows the study of cell culture in a time-course experiment without any cell damage. Determination of the release of amino acid metabolites that initially were not present in the media provides more reliable information about the processes of growth and differentiation in comparison with determination of amino acid consumption rates. Homoarginine (hArg), a derivative of arginine, is generated as the minor product in the reaction catalyzed by L-Arginine: glycine amidinotransferase, where L-lysine serves as an acceptor for amidine group instead of glycine. Ornithine is another product generated in this reaction from arginine. Thus, the goal of the present study was to evaluate the rate of hArg and ornithine accumulation in comparison to the rate of consumption of other amino acids in the course of C2C12 myoblast differentiation. The release time profiles were similar for hArg and ornithine, with the maximum corresponding to the second day of differentiation. The shift for hArg at this time point was detected with greater reliability (p &lt; 0.002) than for ornithine and other amino acids. We suggest that hArg and ornithine could serve as markers to monitor the processes of myoblasts growth and differentiation.</p> Alexandr Zhloba Tatiana Subbotina Stanislava Prikhodko Alexandr Khudiakov Natalia Smolina Anna Kostareva ##submission.copyrightStatement## 2018-11-30 2018-11-30 63 3 174–179 174–179 10.21638/spbu03.2018.303 Multiparametric comparative analysis of coelomocytes in <em>Asterias amurensis</em> and <em>Lysastrosoma anthosticta</em> <p>Behavioral dynamics of coelomocytes from echinoderms <em>Asterias amurensis</em> and <em>Lysastrosoma anthosticta</em> during the first hour of in vitro cultivation was analyzed using a wide range of linear and fractal parameters of the external morphology. Most of the parameters, including values of the cell bounding circle and convex hull, asymmetry, fractal dimensions of contour images, lacunarity, and cell density and area, showed species-specific behavior of the immune cells of the studied animals. The cells differed in a wide range of parameters as early as two min after seeding on the substrate. The cells acquired the largest morphological differences by the fifth min of cultivation. Both cell dynamics in general and analysis of the cell morphology at individual points in time may serve as markers for species-specificity of cells. However, when morphology is compared at one point in time, at least two parameters associated with significant morphological differences in cells of the studied species should be used because of overlapping tendencies in changes in morphological features.</p> Yuriy Karetin Eugenia Pimenova ##submission.copyrightStatement## 2018-11-30 2018-11-30 63 3 180–188 180–188 10.21638/spbu03.2018.304 Temporal and spatial variability of environments drive the patterns of species richness along latitudinal, elevational, and depth gradients <p>This paper seeks to shed light on the primary causes of the latitudinal cline in species diversity, the asymmetry in species richness between the northern and southern hemispheres, and various patterns of species richness along mountain and continental slopes, which are at present of central interest in ecology. To that end, we restate, further develop and unify Janzen’s ideas about the higher fidelity of tropical organisms to their habitats; the notions of Sanders on temporal and spatial variations of environment and their impact on the breadth of species adaptations; the hypothesis of latitude-niche breadth and niche overlap; the theories of climatic stability, competitive exclusion and competitive divergence with the incorporation of some elements of the gradient model of diversification. We argue that during adaptation to a wide range of the same environmental factors in time, the high latitude species also become adapted to a wide range of those factors in space. As a result, they form not only very wide, but also widely overlapping ecological niches. This eventually leads to the competitive extinction of many species and a general impoverishment of biota. In contrast, relatively stable environments allow species to move more and more towards specialization with a simultaneous narrowing of their ecological niches that in turn leads to a reduction of niche overlap and greater species packing in communities. In tropical mountains and on the continental slope, where the environment is stable enough, the degree of its differentiation depends mainly on the steepness of slope. And since the steepest slopes tend to be located at intermediate elevations and intermediate bathyal depths, it is there that there are conditions for the highest specialization. These ideas can provide a framework for new approaches to biodiversity conservation of different regions.</p> Nikolay Kolomiytsev Nadezhda Poddubnaya ##submission.copyrightStatement## 2018-11-30 2018-11-30 63 3 189–201 189–201 10.21638/spbu03.2018.305 Erratum to: Phylogenetic relationships of psammosteid heterostracans (Pteraspidiformes), Devonian jawless vertebrates by Vadim Glinskiy Vadim Glinskiy ##submission.copyrightStatement## 2018-11-30 2018-11-30 63 3 202 202 10.21638/spbu03.2018.306