MORPHOLOGY OF THE FIRST MANDIBULAR TOOTH MICROTUS GREGALIS (RODENTIA, ARVICOLINAE) FROM THE MIDDLE PLEISTOCENE OF THE PRE-ALTAI PLAIN

In this paper morphological structure of the first lower molar m1 tooth of the narrow-skulled vole from alluvial deposits of the Pre-Altai Plain Middle Neo-Pleistocene is described. Morphological study of the vole remains showed that they belong to the modern species Microtus gregalis. At the same time, the study sample showed significant differences, both in morphological structure and in the size of the first lower molar, in comparison with the recent representatives of the same territory. The set of morphological and morphometric data shows that the studied voles occupy an intermediate position between M. gregaloides of the Early and M. gregalis of the Late Neo-Pleistocene. The ratio of m1 morphotypes also showed the relative primitiveness of the M. gregalis sampling. Morphological study of remains of the narrow-skulled vole from the Solonovka, Petropavlovskoe and Malinovka-4 locations confirmed the previously determined age for sediments containing the remains of microtheriofauna.

The evolution of body size in termites

Termites are social cockroaches. Because non-termite cockroaches are larger than basal termite lineages, which themselves include large termite species, it has been proposed that termites experienced a unidirectional body size reduction since they evolved eusociality. However, the validity of this hypothesis remains untested in a phylogenetic framework. Here, we reconstructed termite body size evolution using head width measurements of 1638 modern and fossil termite species. We found that the unidirectional body size reduction model was only supported by analyses excluding fossil species. Analyses including fossil species suggested that body size diversified along with speciation events and estimated that the size of the common ancestor of modern termites was comparable to that of modern species. Our analyses further revealed that body size variability among species, but not body size reduction, is associated with features attributed to advanced termite societies. Our results suggest that miniaturization took place at the origin of termites, while subsequent complexification of termite societies did not lead to further body size reduction.

Convergent evolution of polyploid genomes from across the eukaryotic tree of life

By modeling the homoeologous gene losses that occurred in fifty genomes deriving from ten distinct polyploidy events, we show that the evolutionary forces acting on polyploids are remarkably similar, regardless of whether they occur in flowering plants, ciliates, fishes or yeasts. The models suggest these events were nearly all allopolyploidies, with two distinct progenitors contributing to the modern species. We show that many of the events show a relative rate of duplicate gene loss prior to the first post-polyploidy speciation that is significantly higher than in later phases of their evolution. The relatively low selective constraint seen for the single-copy genes these losses produced lead us to suggest that most of the purely selectively neutral duplicate gene losses occur in the immediate post-polyploid period. We also find ongoing and extensive reciprocal gene losses (RGL; alternative losses of duplicated ancestral genes) between these genomes. With the exception of a handful of closely related taxa, all of these polyploid organisms are separated from each other by tens to thousands of reciprocal gene losses. As a result, it is very unlikely that viable diploid hybrid species could form between these taxa, since matings between such hybrids would tend to produce offspring lacking essential genes. It is therefore possible that the relatively high frequency of recurrent polyploidies in some lineages may be due to the ability of new polyploidies to bypass RGL barriers.

The history of body size evolution in termites

Termites are social cockroaches. Because non-termite cockroaches are larger than basal termite lineages, which themselves include large termite species, it has been proposed that termites experienced a unidirectional body size reduction since they evolved eusociality. However, the validity of this hypothesis remains untested in a phylogenetic framework. Here, we reconstructed termite body size evolution using head width measurements of 1638 modern and fossil termite species. We found that the unidirectional body size reduction model was only supported by analyses excluding fossil species. Analyses including fossil species suggested that body size diversified along with speciation events and estimated that the size of the common ancestor of modern termites was comparable to that of modern species. Our analyses further revealed that body size variability among species, but not body size reduction, is associated with features attributed to advanced termite societies. Our results suggest that miniaturization took place at the origin of termites, while subsequent complexification of termite societies did not lead to further body size reduction.

The modern species composition of the family Chenopodiaceae Vent. (Amaranthaceae Juss.) of the flora of the desert part of the Syrdarya river valley

Representatives of the Chenopodiaceae Vent. family are the hallmark of the flora of the desert regionsof Kazakhstan, as they far outnumber other leading families. Moreover, this applies not only to the flora of the mountainousterritories, but also to the flora of the river valleys, in particular, the flora of the wide valley of the Syrdarya river. Thepredominance of Chenopodiaceae is due to the excellent adaptability of its species to desert conditions. Quite a few speciesof Chenopodiaceae are dominant plant communities, especially in the middle deserts of the North Turan province. Amongthem there are many species that have useful properties (forage, landscape, medicinal, etc.). The aim of the work was toidentify the current species composition of the Chenopodiaceae family (Amaranthaceae Juss.) of the flora of the desertpart of the Syrdarya river valley. Classical botanical methods were used in the research process. As a result of the conductedstudies, the modern species composition of the Chenopodiaceae family of the studied territory, consisting of 112 speciesfrom 38 genera, was revealed. The three largest genera include genera: Salsola–17 species, Atriplex–15 species, Suaeda–11species. The remaining genera contain from 6 to 1 species. Genera represented by a small number of species predominate(26 genera of 1–2 species each).

Cochlear shape distinguishes southern African early hominin taxa with unique auditory ecologies

Insights into potential differences among the bony labyrinths of Plio-Pleistocene hominins may inform their evolutionary histories and sensory ecologies. We use four recently-discovered bony labyrinths from the site of Kromdraai to significantly expand the sample for Paranthropus robustus. Diffeomorphometry, which provides detailed information about cochlear shape, reveals size-independent differences in cochlear shape between P. robustus and Australopithecus africanus that exceed those among modern humans and the African apes. The cochlea of P. robustus is distinctive and relatively invariant, whereas cochlear shape in A. africanus is more variable, resembles that of early Homo, and shows a degree of morphological polymorphism comparable to that evinced by modern species. The curvature of the P. robustus cochlea is uniquely derived and is consistent with enhanced sensitivity to low-frequency sounds. Combined with evidence for selection, our findings suggest that sound perception shaped distinct ecological adaptations among southern African early hominins.

Diversity of Algae and Cyanobacteria and Bioindication Characteristics of the Alpine Lake Nesamovyte (Eastern Carpathians, Ukraine) from 100 Years Ago to the Present

The species diversity and changes in the structural dynamics of the algal flora from the alpine lake Nesamovyte has been studied for 100 years. During the period of investigations, 234 species (245 infraspecific taxa) were revealed to cover more than 70% of the modern species composition of the studied lake. The modern biodiversity of algae is characterized by an increase in the number of widespread forms, a change from the baseline “montane” complex in comparison to the beginning of the 20th century. Nevertheless, the Nesamovyte Lake still has a unique algae composition that is typical for high-mountainous European lakes. The presence of a different complex of conventionally arctic species of algae, in particular, diatoms is discussed. Structural changes in the taxonomic composition of the algal flora of the lake as well as in the complex of the leading genera, species and their diversity are revealed. An ecological analysis of the algal species composition of the lake showed vulnerability and degradation to the ecosystem of the lake. On this basis, the issue regarding the question of protection and preservation of the algae significance and uniqueness of the flora of algae in the Nesamovyte Lake are discussed.

Modern and fossil insects body size as a possible proxy to understand environments of the past

<p>The fossil records of Insects is quite rich and abundant, telling a story of the group’s rise through the Paleozoic, with the subsequent conquest of sea, land, freshwater and finally, for the first time in history of animals – air. Fossil insects also can tell us about the environment they lived in. It is relatively common to use insect remnants, especially head capsules of  non-biting midges (Diptera, Chironomidae) preserved in the sediments from the period including several last Ice ages the Holocene (11650 Years BC – Present) to reconstruct temperatures and the climate patterns of the past. Most of the midges in the Holocene are representatives of modern species, which allows us to extrapolate their ecology from the modern representatives of the same species. Based on our knowledge of the temperature preference of this modern species we can quite easily reconstruct and model their temperature preferences in the past.</p><p>Reconstruction of the temperature optimums of all the taxa in the community, together with analyses of the other paleoecological proxies (i.e. plant pollen profiles) enables us to assess the range of the temperatures experienced by the area in which midge samples of Chironomidae was obtained in the Holocene and latest Pleistocene. We cannot rely on such ecological extrapolation from the modern animals' ecology for the animal’s fossil records from the deep past, for example from Cretaceous or Triassic periods.</p><p>Therefore, we are proposing a more universally applicable climate proxy, independent of our knowledge of the fossil organism’s ecology. Animal size is one of the best candidates for such proxy. It is well known that the body size of the homoeothermic (“warm-blooded”) animals follows (roughly) so-called Bergman rule when size within the group of organisms is increasing from South to North ( i.e. polar bear and Amur tiger are both the northernmost and the largest representatives of their respective groups). We hypothesized that flies (Diptera) are suitable candidates for a quantitative paleoclimate proxy. Flies are very abundant in the fossil records from the mid Triassic (245 Mya) up until modern time. Their size is appears directly negatively correlated with temperature, i.e. representatives occurring further North are larger than the ones from the equatorial regions. This relationship allows us to use the relationships between the insect size and the geographic latitude at which they occur and the temperature at which these insects occur. Here we present a first results from analysis of > 2000 species of Chironomidae from around the globe, in a phylogenetic-constrained framework. First results are showing that non-biting midge’s wing and body size is growing by about 0.02 mm per one degree of geographical latitude, as one moves from the equator, mostly regardless of the phylogenetic position of the species analysed. This first results are showing that Insect size might be a promising proxy for reconstructing the palaeotemperature.</p><p> </p><div> <div> </div> </div>