Higher Taxonomic Richness Research Articles

Short-term influence of biochar and fertilizer-biochar blends on soil nutrients, fauna and maize growth

Use of inorganic fertilizers in smallholder cropping systems in Africa is often becoming inefficient due to increasing unresponsiveness to fertilizer application. A study was conducted for 2 years (four seasons) to assess the effects of biochar made from Prosopis juliflora (Sw.) DC. biomass on nutrients, fauna abundance and subsequent influence on maize planted in a nitisol. There were 12 amendments comprising: (i) biochar applied alone at a rate of 5 and 10 Mg ha−1; (ii) three fertilizer types applied separately (di-ammonium phosphate (18:46:0), urea (46:0:0) and composite NPK (23:23:0)); (iii) six fertilizer + biochar blends of the three fertilizer types and two biochar rates (0.05 and 0.1 Mg ha−1); and (iv) a control with no inputs. Treatments were replicated four times in a randomized complete block design. The amendments were applied in the first two seasons, while the last two were used to assess residual effects. At the end of the first two seasons, total C and N were higher in soils where biochar or fertilizer + biochar was applied, with more than 15.0 g C and 1.9 g N kg−1, compared to 10.4 g C and 1.0 g N kg−1 in control plots. Available P and exchangeable K were over 200% and 100% higher in biochar or fertilizer + biochar amended than control soils, respectively. Application of biochar had no effects on macrofauna such as beetles, centipedes, millipedes, termites and ants, but attracted earthworms. Soil that received 10 Mg biochar ha−1 recorded twice the number of earthworms (207 individuals m−2) compared to soil with 5 Mg biochar ha−1 (105 individuals m−2) and control (97 individuals m−2). Soils which received biochar, with or without fertilizer, had higher taxonomic richness (7.0 species) compared to soils which received DAP (2.8) or NPK (3.8). Nematodes, particularly bacterivorous groups, decreased by more than eight times with biochar application. In the first and second seasons, 5.6 Mg maize grain yield ha−1 was obtained from plots amended with biochar (without fertilizer), which was about six times higher than that harvested from unfertilised control at 0.9 Mg ha−1. Yield differences in plots where fertilizer was applied with or without biochar were not significant. Yield in the third and fourth seasons declined to 3.2 and 1.5 Mg ha−1, irrespective of fertilizer type or biochar amounts.

Diversity and phenology of hoverflies (Diptera: Syrphidae) in pine forests (Pinus halepensis Miller) of Algeria

Hoverflies are good indicators of ecosystem integrity, especially in drylands. However, the key factors explaining hoverfly diversity in North African forest ecosystems are still not addressed. The current study provides data on the diversity, structure and functional trophic groups (FTG) of the hoverfly community in Aleppo pine forests under a semi-arid climate in northeastern Algeria. Using an entomological net, hoverflies were sampled weekly during 2008–2009. Alpha and beta-diversity of hoverflies and functional trophic group (FTG) were analyzed using several parameters and indices (e.g. species composition, richness, occurrence, diversity, estimations, similarity, etc.). In total, 602 individuals of 21 species were collected with a constant species (Eupeodes corollae) and four common species (Episyrphus balteatus, Chrysotoxum intermedium, Eristalis arbustorum and Eristalis tenax). Most species (17) occurred accidentally or very accidentally in samples. The highest diversity was recorded during spring, corresponding to the flowering season of most understory plant species. Seasonal rarefaction and extrapolation curves indicated that the expected species richness would be higher in autumn and spring compared to summer and winter. The spectrum of FTG ranked predators first with 52.4% of species, followed by saprophagous (42.8%) and then phytophagous (4.8%) species. Hoverfly communities showed high taxonomic richness and alpha-diversity all over the year, with peaks during spring that coincides with flowering period of most plant species of the forest understorey and favourable climatic conditions.

High-throughput environmental DNA analysis informs a biological assessment of an urban stream.

There is growing interest in the use of DNA barcoding and metabarcoding approaches to aid biological assessments and monitoring of waterbodies. While biodiversity measured by morphology and by DNA often has been found correlated, few studies have compared DNA data to established measures of impairment such as multimetric pollution tolerance indices used by many bioassessment programs. We incorporated environmental DNA (eDNA) metabarcoding of seston into a rigorous watershed-scale biological assessment of an urban stream to examine the extent to which eDNA richness and diversity patterns were correlated with multimetric indices and ecological impairment status designations. We also evaluated different filtering approaches and taxonomic classifications to identify best practices for environmental assessments. Seston eDNA revealed a wide diversity of eukaryotic taxa but was dominated by diatoms (36%). Differentiation among sites in alpha and beta diversity was greater when operational taxonomic units (OTUs) were classified taxonomically, but coarse resolution taxonomy (kingdom) was more informative than finer resolution taxonomy (family, genus). Correlations of DNA richness and diversity with multimetric indices for fish and macroinvertebrates were generally weak, possibly because Metazoa were not highly represented in our DNA dataset. Nonetheless, sites could be differentiated based on ecological impairment status, with more impaired sites having lower eDNA diversity as measured by the Shannon index, but higher taxonomic richness. Significant environmental drivers of community structure, as inferred from constrained ordination analyses, differed among kingdoms within the eDNA dataset, as well as from fish and macrobenthos, suggesting that eDNA provides novel environmental information. These results suggest that even a simple seston eDNA filtering protocol can provide biodiversity information of value to stream bioassessment programs. The approach bears further investigation as a potentially useful rapid assessment protocol to supplement more intensive field sampling efforts.

Distribution and habitat preference of Ephemeroptera and Trichoptera in subtropical mountain streams: implications for monitoring and conservation.

The assessment of biotic-habitat relationships provides key information to predict biotic responses to perturbations and important tools for river management and monitoring. This study aimed to assess the spatial distribution of Ephemeroptera and Trichoptera in mountain streams of central Argentina. We evaluated the effect of seasonality and identified the variables conditioning the abundance of the assemblages and the habitat with the highest taxonomic richness. Sampling was carried out in four streams (Carcarañá River basin) during high and low water periods. Three lotic habitats were sampled: riffles, coarse substrate runs, and fine substrate runs; and physicochemical and habitat variables were measured. We found differences in assemblage composition, among the 25 genera of Ephemeroptera and Trichoptera, at the habitat level. The most important variables affecting distribution patterns were substrate and flow type, but macroalgae and organic matter (twigs, leaves, and detritus) were also important predictors. Riffles maintained the highest richness but when considering only the Ephemeroptera taxa, fine substrate runs emerged also as an important habitat for these taxa. Our study provided valuable ecological information related to habitat preference of taxa with a key role in stream functioning and of great usefulness for the monitoring of lotic systems.

Floristic structure and composition of Guadua forests in the Colombian coffee region1

ABSTRACT In the coffee region (900-2,000 m a.s.l.) of the Colombian Andes, the forest remnants correspond mainly to fragments dominated by the bamboo species Guadua angustifolia Kunth (Guadua). These highly fragmented forests are found in landscapes with a high degree of transformation due to the agricultural activity and urban expansion. With the purpose of contributing to the knowledge of the ecological characteristics of these forests, the floristic structure and composition (alpha, beta and gamma diversity) of seven forest fragments located in the middle (Quindío) and lower basins of the La Vieja river (Risaralda) were studied. A total of 70,961 individuals and 172 species belonging to 54 families were found. Fifty percent of the families were represented by only one species, and the families Araceae and Leguminosae showed the highest taxonomic richness, respectively with 21 and 14 species. The diversity indices for these forests revealed values comparable to those of tropical forest ecosystems (Shannon-Weiner values between 3,167 and 3,798). Likewise, the cluster analysis (based on Euclidean distances) showed that the stands present a similarity below 0.65 (65 %), associated with the 35 species reported, in seven fragments that characterize a varied floristic composition. This finding implies that these fragments should not be seen as isolated units, but as sites embedded in a diverse regional landscape. This represents important habitats for these species, which are capable of maintaining significant levels of diversity, even under management conditions.

Impact of violacein from Chromobacterium violaceum on the mammalian gut microbiome.

Violacein is a violet pigment produced by Chromobacterium violaceum that possesses several functions such as antibacterial, antiviral, antifungal, and antioxidant activities. The search for potential compounds and therapies that may interfere with and modulate the gut microbial consortia without causing severe damage and increased resistance is important for the treatment of inflammatory, allergic, and metabolic diseases. The aim of the present work was to evaluate the ability of violacein to change microbial patterns in the mammalian gut by favoring certain groups over the others in order to be used as a therapy for diseases associated with changes in the intestinal microflora. To do this, we used male Wistar rats, and administered violacein orally, in low (50 μg/ml) and high (500 μg/ml) doses for a month. Initially, the changes in the microbial diversity were observed by DGGE analyses that showed that the violacein significantly affects the gut microbiota of the rats. Pyrosequencing of 16S rDNA was then employed using a 454 GS Titanium platform, and the results demonstrated that higher taxonomic richness was observed with the low violacein treatment group, followed by the control group and high violacein treatment group. Modulation of the microbiota at the class level was observed in the low violacein dose, where Bacilli and Clostridia (Firmicutes) were found as dominant. For the high violacein dose, Bacilli followed by Clostridia and Actinobacteria were present as the major components. Further analyses are crucial for a better understanding of how violacein affects the gut microbiome and whether this change would be beneficial to the host, providing a framework for the development of alternative treatment strategies for intestinal diseases using this compound.

Agulhas Current properties shape microbial community diversity and potential functionality

Understanding the impact of oceanographic features on marine microbial ecosystems remains a major ecological endeavour. Here we assess microbial diversity, community structure and functional capacity along the Agulhas Current system and the Subtropical Front in the South Indian Ocean (SIO). Samples collected from the epipelagic, oxygen minimum and bathypelagic zones were analysed by 16S rRNA gene amplicon and metagenomic sequencing. In contrast to previous studies, we found high taxonomic richness in surface and deep water samples, but generally low richness for OMZ communities. Beta-diversity analysis revealed significant dissimilarity between the three water depths. Most microbial communities were dominated by marine Gammaproteobacteria, with strikingly low levels of picocyanobacteria. Community composition was strongly influenced by specific environmental factors including depth, salinity, and the availability of both oxygen and light. Carbon, nitrogen and sulfur cycling capacity in the SIO was linked to several autotrophic and copiotrophic Alphaproteobacteria and Gammaproteobacteria. Taken together, our data suggest that the environmental conditions in the Agulhas Current system, particularly depth-related parameters, substantially influence microbial community structure. In addition, the capacity for biogeochemical cycling of nitrogen and sulfur is linked primarily to the dominant Gammaproteobacteria taxa, whereas ecologically rare taxa drive carbon cycling.

Taxonomic diversity of fungi deposited from the atmosphere

Fungi release spores into the global atmosphere. The emitted spores are deposited to the surface of the Earth by sedimentation (dry deposition) and precipitation (wet deposition), and therefore contribute to the global cycling of substances. However, knowledge is scarce regarding the diversities of fungi deposited from the atmosphere. Here, an automatic dry and wet deposition sampler and high-throughput sequencing plus quantitative PCR were used to observe taxonomic diversities and flux densities of atmospheric fungal deposition. Taxon-specific fungal deposition velocities and aerodynamic diameters (da) were determined using a collocated cascade impactor for volumetric, particle-size-resolved air sampling. Large multicellular spore-producing dothideomycetes (da ≥ 10.0 μm) were predominant in dry deposition, with a mean velocity of 0.80 cm s–1 for all fungal taxa combined. Higher taxonomic richness was observed in fungal assemblages in wet deposition than in dry deposition, suggesting the presence of fungal taxa that are deposited only in wet form. In wet deposition, agaricomycetes, including mushroom-forming fungi, and sordariomycetes, including plant pathogenic species, were enriched, indicating that such fungal spores serve as nuclei in clouds, and/or are discharged preferentially during precipitation. Moreover, this study confirmed that fungal assemblage memberships and structures were significantly different between dry and wet deposition (P-test, p < 0.001). Overall, these findings suggest taxon-specific involvement of fungi in precipitation, and provide important insights into potential links between environmental changes that can disturb regional microbial communities (e.g., deforestation) and changes in precipitation patterns that might be mediated by changes in microbial communities in the atmosphere.

Floristic surveys of hydrocarbon-polluted sites in some Cameroonian cities (Central Africa)

ABSTRACTSoils pollution with hydrocarbons is on the increase, especially in developing countries like Cameroon. Identifying plant species capable of growing on hydrocarbon-polluted soils remains an essential step in phytoremediation, a low cost, solar energy driven clean up technique in which living green plants are used. Here, we report floristic surveys conducted in 4 cities of Cameroon to identify plants with phytoremediation capacities. A total of 13 hydrocarbon-polluted sites were surveyed in each city using the quadrat method. Unpolluted sites served as the control. 106 species belonging to 76 genera and 30 families were identified on hydrocarbon-polluted sites. Plant diversity was shown to be higher (166 species contained in 125 genera and 50 families) in the control sites. Poaceae, Cyperaceae, Asteraceae and Amaranthaceae families have a higher taxonomic richness on polluted sites (16, 15, 10 and 8 taxa respectively). Shannon diversity index of the hydrocarbon-polluted sites (1.6 to 2.7 bits/ind.) were significantly lower than the control sites (2.7 to 3.2 bit/ind.). Based on a relative frequency > 10% and abundance > 7%, our results show that more than 15 plant species could be tested in preliminary trials to determine their phytoremediation/cleaning-up capacities on hydrocarbon-polluted soils in the tropics.

Spatial variation in biodiversity patterns of neuston in the Western Mediterranean and Southern Adriatic Seas

Neuston - comprising a diverse assemblage of organisms living in the surface layer of the water column - plays a unique ecological role in marine life. Notwithstanding its importance, quantitative information on its spatial structure are still limited, in particular for the Mediterranean Sea.Here, the spatial structure of neuston assemblage of the Western Mediterranean and the Southern Adriatic Seas was analysed, with particular emphasis on the biodiversity pattern in the two study areas. A total of 59 stations were sampled in an oceanographic cruise conducted in May–June 2013. Additional analyses were performed on data on 21 stations sampled in the Southern Adriatic in March 2015 in order to confirm the generality of the patterns observed in the 2013 cruise. Geostatistical analyses indicated that in 2013 in the Southern Adriatic the variation in taxonomic richness, abundance, and ecological diversity of the neuston across stations was characterized by a significant spatial autocorrelation. Conversely, in the Western Mediterranean a negligible spatial structure was observed. In addition, the taxonomic richness and ecological diversity of the neuston resulted significantly higher in Southern Adriatic than in the Western Mediterranean. Data collected in the 2015 cruise confirmed a high taxonomic richness and diversity for the Southern Adriatic; furthermore, a significant spatial autocorrelation was observed for both parameters. The present study represents an original insight into the structure of the neuston community in the Mediterranean Sea, providing strong evidence of the spatial variability of its diversity patterns. The influence of local and large-scale processes is discussed, and the need of more extended investigations is emphasized.

Formation of groupings of mayfly larvae (Ephemeroptera) in the area of small hydrological structures, in the streams of the Kamienica Nawojowska river basin (the Sądeckie Beskids, Poland)

Abstract Anthropogenic modification of abiotic factor in turn influencez biotic communities. The aim of this study was to characterise clusters of mayflies in selected streams of Kamienica Nawojowska river basin in conjunction with small, lateral hydrological structures that have been built in this area. There was an attempt to determine whether and to what extent small lateral hydrological structures affect larvae of mayflies in the examined mountain streams. An analysis of the taxonomic composition of mayfly clusters in the examined stream sections was carried out. For this purpose, the author described the taxonomic wealth, variation in the density of organisms, the domination structure within taxonomic groups and trophic functional groups, taxonomic variation (based on the Shannon-Winner factor), constancy of occurrence (according to the Szujecki formula) as well as faunistic similarity (according to the Jaccard formula). An emphasis was also placed on the species included in the Red List of Vulnerable and Endangered Species in Poland (2002). The obtained results indicate a high taxonomic richness and a large diversity of mayfly fauna on the examined stream sections. There were no significant differences, however, in this aspect between posts situated upstream and downstream from the hydrological structures. The formation of clusters was influenced not so much by small hydrological structures as by other abiotic factors such as the nature of the bottom substrate, the way in which the basin is used, the location of a particular post on a particular watercourse section as well as other anthropogenic activities (e.g. those related to forest management). A comparison of the obtained data with the results of the research conducted before the completion of major regulatory works in Kamienica Nawojowska river basin showed that the mayfly fauna had preserved a large taxonomic richness, although some changes had occurred in the structure of the clusters. However, further research related to this issue is needed, especially in other river basins of the Beskids.

Using legumes as indicators in the seasonally dry vegetation types in South America

The South American corridor of seasonally dry vegetation (SACSV) includes different types of physiognomies forming a continuous corridor with high biodiversity and endemism; however, little attention has been paid to the conservation of the SACSV. As this is an area with great diversity, cataloguing all the species is challenging. Thus, we suggest the use of Leguminosae species (trees and shrubs) as bioindicators of the different types of vegetation present in the area and to identify priority areas for conservation of the SACSV, since the family is highly represented in this vegetation. The study area was divided into 358 grid cells with recorded specimens. For each grid cell, species richness, taxonomic diversity, number of species restricted to one type of vegetation, and threatened and indicator species of phytogeographic domain were calculated. To determine the phytogeographic domains and indicator species, analysis of similarity, cluster and indicator species (ISA) were performed. The results show that 43% of the grid cells (154) have high biological importance for conservation (high taxonomic diversity, species richness and number of restricted species), all of which lie outside of protected areas. We identified 72 indicator species for seven floristic units, which, in general, include areas of the same phytogeographic domain, supporting the existing classification systems. We suggest that for effective conservation of biodiversity present in the SACSV, it is necessary to establish protected areas throughout the SACSV.

Urban ponds as an aquatic biodiversity resource in modified landscapes.

Urbanization is a global process contributing to the loss and fragmentation of natural habitats. Many studies have focused on the biological response of terrestrial taxa and habitats to urbanization. However, little is known regarding the consequences of urbanization on freshwater habitats, especially small lentic systems. In this study, we examined aquatic macro-invertebrate diversity (family and species level) and variation in community composition between 240 urban and 782 nonurban ponds distributed across the United Kingdom. Contrary to predictions, urban ponds supported similar numbers of invertebrate species and families compared to nonurban ponds. Similar gamma diversity was found between the two groups at both family and species taxonomic levels. The biological communities of urban ponds were markedly different to those of nonurban ponds, and the variability in urban pond community composition was greater than that in nonurban ponds, contrary to previous work showing homogenization of communities in urban areas. Positive spatial autocorrelation was recorded for urban and nonurban ponds at 0-50km (distance between pond study sites) and negative spatial autocorrelation was observed at 100-150km and was stronger in urban ponds in both cases. Ponds do not follow the same ecological patterns as terrestrial and lotic habitats (reduced taxonomic richness) in urban environments; in contrast, they support high taxonomic richness and contribute significantly to regional faunal diversity. Individual cities are complex structural mosaics which evolve over long periods of time and are managed in diverse ways. This facilitates the development of a wide range of environmental conditions and habitat niches in urban ponds which can promote greater heterogeneity between pond communities at larger scales. Ponds provide an opportunity for managers and environmental regulators to conserve and enhance freshwater biodiversity in urbanized landscapes whilst also facilitating key ecosystem services including storm water storage and water treatment.

Testate Amoebae (Amebozoa: Arcellinida) in Tropical Lakes of Central Mexico.

Testate amoebae are common single-celled eukaryotic organisms in aquatic ecosystems. Despite their important role in these ecosystems, and their potential as bioindicators and paleoindicators, they remain poorly studied in Mexico. The major objectives of this study were to: 1) increase knowledge of testate amoebae in Mexico’s tropical lakes, and 2) create a catalog of high-quality scanning electron micrographs that can be used for future ecological and paleoenvironmental studies. We collected surface-sediment samples from 29 lakes, located in the Transmexican Volcanic Belt, one at each lake during June and October 2011, and March 2013. Sediments were collected with an Ekman grab and preserved in anhydrous ethanol. Sub-samples were observed under a stereomicroscope and morphometric data for each species were recorded. Total diameter and aperture diameter were measured on circular tests. Irregularly shaped tests were measured for length and width of the aperture and for the size of the whole test. If a specimen possessed spines, the length of one randomly selected spine was measured. The best-preserved specimen of each taxon was photographed with an optical microscope and a scanning electron microscope (SEM). We found 41 taxa of testate amoebae belonging to the genera: Arcella, Argynnia, Centropyxis, Cucurbitella, Cyclopyxis, Cyphoderia, Difflugia, Euglypha, Lesquereusia, Pentagonia, Pseudodifflugia and Scutiglypha. Twelve species not previously reported for Mexico were recorded, along with 13 varieties. The average number of taxa recorded in each lake was eight, and the highest taxonomic richness was 18. The taxon found in the greatest number of lakes was Centropyxis aculeata var. aculeata. Taxonomic richness varied among lakes in the same region. This could reflect lake-specific differences in environmental conditions, underscoring the need for more detailed studies that include collection of data on physical and chemical variables in the lakes. Our results highlighted the need of further studies for the distribution patterns and ecology of lacustrine testate amoebae.

Floristic survey of flowering plants in a tropical coastal ecosystem in Veracruz, Mexico

Mexico is a megadiverse country and Veracruz is one of the states with the highest floristic diversity. The reserve of La Mancha in central coastal Veracruz comprises several vegetation types. In this site we conducted for a year, monthly surveys of flowering or fruiting plants in six vegetation types, considering the frequency of occurrence of different species. We found a total of 147 species (131 genera and 63 families). The families most represented were Asteraceae, Fabaceae and Verbenaceae. In addition, we found nine species that had not been reported in previous floristic studies. The highest taxonomic richness was observed in the tropical deciduous flood forest with wetland (59 species), while the highest diversity was found in tropical deciduous forest (ISI = 0.9562). We also found that the most similar vegetation types based on the composition and frequency of species were, coastal dune scrub, tropical deciduous forest and pioneer dune vegetation. The dominant plant biological form in La Mancha were herbs (40.41 %) followed by shrubs (23.97 %), vines-lianas (18.49 %) and trees (17.12 %). This study is the first to consider the frequency-occurrence of flowering and fruiting plants in La Mancha, covering six vegetation types through one year. The more relevant results of this study show the diversity of plants in different environments using the frequency of each species based on reproductive events. This information could be useful in future researches that evaluate plant-animal interactions, like pollination and seed dispersal.

Ancient origin of high taxonomic richness among insects.

Insects are a hyper-diverse group, comprising nearly three-quarters of all named animal species on the Earth, but the environmental drivers of their richness and the roles of ecological interactions and evolutionary innovations remain unclear. Previous studies have argued that family-level insect richness increased continuously over the evolutionary history of the group, but inclusion of extant family records artificially inflated the relative richness of younger time intervals. Here we apply sampling-standardization methods to a species-level database of fossil insect occurrences, removing biases present in previous richness curves. We show that insect family-richness peaked 125 Ma and that Recent values are only 1.5-3 times as high as the Late Palaeozoic. Rarefied species-richness data also tentatively suggest little or no net increase in richness over the past 125 Myr. The Cretaceous peak in family richness was coincident with major radiations within extant groups but occurred prior to extinctions within more basal groups. Those extinctions may in part be linked to mid-Cretaceous floral turnover following the evolution of flowering plants. Negligible net richness change over the past 125 Myr implies that major radiations within extant groups were offset by reduced richness within groups that are now relict or extinct.

Relations between environmental gradients and diversity indices of benthic invertebrates in lotic systems of northern Italy

Abstract. The relations between environmental gradients, as measured by 19 independent variables, and traditional diversity indices (taxonomic richness, diversity and evenness) of benthic macroinvertebrate communities in the lotic systems of northern Italy were analyzed. Redundancy analysis (RDA) was used to describe the response of taxa to environmental gradients. Diversity indices were analyzed using generalized linear models (GLMs) with explanatory variables the first two major RDA axes. The results from RDA showed that taxa variance is mostly explained by altitude/latitude and combined pollution gradients. Taxonomic richness and diversity was higher in the low polluted upland sites (LPUs) in comparison to high polluted lowland sites (HPLs), suggesting that headwater streams have higher taxonomic richness than downstream reaches. On the other hand, evenness was lower in LPUs, probably due to the dominance of some taxa (e.g., Plecoptera) that are more tolerant of colder conditions.

Materials to diatom flora of Moscow Region: naviculoid diatoms of Meleevsky Stream (Zvenigorod Biological Station)

The article contains a brief review of investigation of diatom flora of S. N. Skadovsky Zvenigorod Biological Station (Moscow Region). Until present the shallow streams of Moscow Region and European Russia did not attract a proper attention of the diatomologists that makes this study important. To date studies of algae of Meleevsky Stream have not been conducted. The stream flows a in spruce forest, its valley is swampy and water is characterized by circumneutral pH values and medium electrolyte content. The list of 98 species, varietes and morphotypes of naviculoid diatoms belonging to 18 genera found in epipelon of the watercourse is provided. For all taxa brief descriptions and light or electron micrographs are given. The highest taxonomic richness was observed in the genera Pinnularia (23 taxa), Sellaphora (17) and Stauroneis (13). 3 genera and 47 species and varietes are new for the flora of Zvenigorod Biological Station (marked with * in the text), 21 species are new records for Moscow Region (marked with **). On the one hand the work broadens our knowledge of diatom flora of Moscow Region, on the other hand it contrubutes to the data on diatom biodiversity in small forest streams of European part of Russia neglected by researchers.

Diversity, distribution and habitat requirements of aquatic insect communities in tropical mountain streams (South-eastern Guinea, West Africa)

Considering that knowledge of the biodiversity of a region is the first step toward its conservation and given the paucity of studies on aquatic insects from the Simandou streams, the diversity of these communities was assessed. Aquatic insects were sampled with a hand-net (mesh size: 250 μm) on four occasions between March 2011 and September 2012 at 27 sites. Environmental variables were also recorded. Overall, 129 taxa belonging to 51 families and eight orders were recorded. Multivariate analyses gathered sites into three clusters in regard to aquatic insect composition. The rarefied taxonomic richness showed decreases in association with increasing levels of human impact. Cluster 1 that contained most disturbed sites displayed low taxonomic richness compared with the two others. The highest taxonomic richness was registered in cluster 2 that contained a mixture of upland and lowland sites; the latter remained minimally disturbed. These sites could be considered as reference sites in studies for assessing water quality. Generalised additive models calculated for the most frequent taxa showed that water temperature, dissolved oxygen, conductivity and pH were the incorporated explanatory variables. Therefore, further anthropogenic activities should preserve the surrounding forest in order to preserve the quality of Simandou streams and consequently aquatic biodiversity.

A new endothiodont dicynodont (Therapsida, Anomodontia) from the Permian Ruhuhu Formation (Songea Group) of Tanzania and its feeding system

ABSTRACTCranial material of the dicynodont Endothiodon from the middle fossiliferous horizon of the Permian Ruhuhu Formation (Ruhuhu Basin, Tanzania) is described as a new species, E. tolani. Endothiodon tolani is distinguished from other Endothiodon species by the absence of a pineal boss and the presence of tusks in most specimens. Although some parts of the Ruhuhu Formation probably correlate with the Eodicynodon or Tapinocephalus assemblage zones of the South African Karoo Basin, it is uncertain whether E. tolani is older than E. bathystoma or E. mahalanobisi. There is less evidence for extensive anteroposterior translation of the mandible in E. tolani than in other dicynodonts. The jaw joint is specialized for allowing some medial-lateral motion. Mastication involved unilateral chewing. Flexure of the postdentary bones relative to the fused dentaries permitted the posterolaterally directed rows of teeth on one side of the skull and mandible to move past one another. The long tooth rows and prominent horn-covered ridges and grooves on the palate and mandible of Endothiodon are unique among dicynodonts. Comparisons with other taxa suggest that its feeding system may have been specialized for cutting three-dimensional objects such as stems or rhizomes. The dicynodont feeding system is very stereotyped throughout the clade's history, but Endothiodon escaped the constraints that affected other dicynodonts, allowing it to evolve a unique skull morphology. This evolutionary flexibility did not translate into high taxonomic richness (we recognize only three species of Endothiodon), but Endothiodon was able to achieve high levels of relative abundance in some basins.http://zoobank.org/urn:lsid:zoobank.org:pub:9686F708-2E6E-40EB-956F-05659889684FSUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP