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2.
The region between the Oka and Volga rivers has been largely neglected with respect to tardigrade biodiversity. In the present
study a total of 21 species from 7 genera, 3 families, 2 orders and only 1 class of tardigrades were present, and some of
their ecological preferences were noted. The tardigrades in the studied region were mainly cosmopolitan. Eurytopic, hygrophilic
and xerophilic species were common while obligate freshwater species were not found. There is a marked similarity in the tardigrade
fauna within similar habitats from different locations within the region. 相似文献
3.
Species that are dependant on, or adapted to, freshwater environments are found in almost all mammalian orders, and two orders,
the Cetacea and the Sirenia, are strictly aquatic and include some freshwater-dependant species. Overall, the aquatic and
freshwater-dependant species represent around 70 of the more than 1,200 living or recent genera of mammals, and occur in all
continents except Antarctica. They include some of the most endangered species of mammals, and several have gone extinct or
become critically endangered in recent decades. One of the main threats is habitat loss or degradation. This chapter provides
an overview of the freshwater species within each order of mammals, their evolutionary history, their relations to humans
and their conservation status.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
5.
The unsaturated zone in fissured (= karstic) aquifers continues to be a source of new species of Harpacticoida (Crustacea:
Copepoda). The first species were discovered about 70 years ago in the Škocjanske Jame Cave in Slovenia. Intensive sampling
of percolating water in caves there over the last 20 years has yielded several new species, some of them well adapted to that
environment. The most recent studies revealed that such a specialised fauna is also present in other regions of Europe, South
and North America, and Asia. In Europe, three genera belonging to the order Harpacticoida are characteristic of the unsaturated
karstic zone: Morariopsis, Paramorariopsis and Elaphoidella. In this article, two highly specialised species of Elaphoidella are described. A detailed analysis of their ecology and morphological adaptations along with other species of the genus Elaphoidella from Slovenia is included, and comparisons are made with the epikarstic genera Morariopsis and Paramorariopsis.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Handling editor: S. I. Dodson 相似文献
6.
Sixteen tardigrade species have been identified from a total of 943 specimens isolated from 69 positive soil samples collected in southern Spain (Andalusia, Huelva). Three genera ( Hexapodibius, Xerobiotus and the new genus Sarascon) and eight species are new records for the Iberian Peninsula, increasing Iberian tardigrade biodiversity by 6%, and 10 species are new records for soil habitats, increasing soil tardigrade biodiversity by 9% (from 96 to 108 species). A newly discovered species and genus are described, followed by an analysis and discussion of the species' phylogenetic position and synapomorphies, based on morphological and total evidence (morphology and molecular – 18S and 28S rRNA – data combined) phylogenetic analyses. The new genus is distinguished from other Itaquasconinae genera, to which it is phylogenetically related, by having a Parascon buccopharyngeal apparatus and Ramajendas claws. In contrast to general eutardigrade evolution, which is primarily determined by claw morphology, itaquasconid evolution is more related to buccopharyngeal apparatus morphology, which shows homoplastic evolution at superfamily, family and subfamily levels, and also defines functional trophic groups in soil-related environments. http://zoobank.org/urn:lsid:zoobank.org:pub:068B9D87-27E2-4B26-8920-FF03CEF9869A 相似文献
7.
Significant differences occurred in the density of tardigrades, rotifers, and nematodes and the diversity of tardigrades between collecting sites located upwind and downwind from a coal-burning power plant in Missouri. The oak tree species and lichen genera also varied in the two areas. Tardigrade and rotifer densities were greater in upwind sites, whereas nematode density was higher in downwind samples. One tardigrade species ( Ramazzottius sp.) was found only at the upwind sites, and one species ( Echiniscus sp.) was only in the downwind samples. In contrast, three species ( Macrobiotus sp., Minibiotus sp., and Milnesium tardigradum) were found both upwind and downwind but in different densities in the two areas. The study presents baseline data for long-term monitoring of the effects of environmental factors on nematode and rotifer densities as well as tardigrade density and diversity. 相似文献
8.
The tardigrade fauna of the African continent is reviewed and presented graphically using Worldmap, a Geographical Information System (GIS) developed for exploring geographical diversity patterns in large biological datasets. References to the African tardigrade fauna have been gathered from published literature and supplemented with unpublished species information from the collection of Prof. Reinhardt M. Kristensen (RMK), Zoological Museum, University of Copenhagen. 156 species belonging to 36 genera of tardigrades are present. They consist of 105 eutardigrade species and 51 heterotardigrade species, of which 42 species are semiterrestrial and 9 species are marine. The presence of tardigrades are reported from 20 countries, but of these 9 are represented by a single reference. Marine tardigrades in particular have been neglected, with only a single report from the shores of the African continent. Data from the RMK collection of samples from Egypt is included in the analysis. The scattered and sparse knowledge of the African tardigrade distribution makes general conclusions difficult, but emphasises the large regions which require further investigation. The current distribution patterns corresponds with easy accessible or ‘tourist’ locations. Regions where GIS could be used to illustrate ecological preferences are also pointed out by the analysis. Isohypsibius malawiensis sp. n. is described from Lake Malawi. It has a smooth body surface and lacks eyes. The heteronych claws are without lunulae, but below the claws a double arched cuticular bar is present. The dorsal and ventral apophyses of the buccal tube have a large drop-shaped swelling. The first macroplacoid is the largest followed by the second, which is only slightly larger than the third; microplacoid is absent. Males are smaller than females. Females lay only one to two very large eggs in the exuvium. The Malpighian tubules are clover-shaped. The new species is interstitial in coarse sediment and no other tardigrade species were present. 相似文献
9.
Terrestrial tardigrades are often found in the lichens and mosses growing on trees and rocks. The assertion that tardigrades
in these habitats are very patchy in their distribution has rarely been backed by quantitative sampling. This study assesses
spatial variability in tardigrade populations inhabiting small patches (0.1 cm 2 to over 5 cm 2) of moss and lichen on trees and rocks at three sites in the United States of America. Tardigrades were collected from four
replicate rocks in the Ouachita Mountains of Arkansas, with 30 lichen patches collected on two adjacent boulders and 20 moss
patches on a second pair of boulders. In Fort Myers and in Citrus Springs, Florida, 30 lichen patches per tree were collected
from two pairs of trees. The tardigrades in each sample were extracted, mounted, identified, and counted. The variation in
tardigrade abundance among lichen or moss patches within rocks or trees was very high; the only consistent pattern was that
very small patches usually lacked tardigrades. Tardigrade diversity and abundance also varied greatly within sites when lichens
and mosses of the same species from different rocks and trees were compared (in the most extreme case one tree had numerous
individuals of two tardigrade species present while the other had almost no tardigrades). The results of this quantitative
sampling support the assertion that tardigrades are very patchy in distribution. Given the considerable time investment required
for the quantitative processing of tardigrade samples, this high spatial variability in tardigrade diversity and abundance
requires that researches testing ecological hypotheses about tardigrade abundance check variability before deciding how many
samples to take. 相似文献
10.
The precise number of extant fish species remains to be determined. About 28,900 species were listed in FishBase in 2005,
but some experts feel that the final total may be considerably higher. Freshwater fishes comprise until now almost 13,000
species (and 2,513 genera) (including only freshwater and strictly peripheral species), or about 15,000 if all species occurring
from fresh to brackishwaters are included. Noteworthy is the fact that the estimated 13,000 strictly freshwater fish species
live in lakes and rivers that cover only 1% of the earth’s surface, while the remaining 16,000 species live in salt water
covering a full 70%. While freshwater species belong to some 170 families (or 207 if peripheral species are also considered),
the bulk of species occur in a relatively few groups: the Characiformes, Cypriniformes, Siluriformes, and Gymnotiformes, the
Perciformes (noteably the family Cichlidae), and the Cyprinodontiformes. Biogeographically the distribution of strictly freshwater
species and genera are, respectively 4,035 species (705 genera) in the Neotropical region, 2,938 (390 genera) in the Afrotropical,
2,345 (440 genera) in the Oriental, 1,844 (380 genera) in the Palaearctic, 1,411 (298 genera) in the Nearctic, and 261 (94
genera) in the Australian. For each continent, the main characteristics of the ichthyofauna are briefly outlined. At this
continental scale, ichthyologists have also attempted to identify ichthyological ‘‘provinces’’ that are regions with a distinctive
evolutionary history and hence more or less characteristic biota at the species level. Ichthyoregions are currently identified
in each continent, except for Asia. An exceptionally high faunal diversity occurs in ancient lakes, where one of the most
noteworthy features is the existence of radiations of species that apparently result from intra-lacustrine speciation. Numerous
fish-species flocks have been identified in various ancient lakes that are exceptional natural sites for the study of speciation.
The major threats to fish biodiversity are intense and have been relatively well documented: overexploitation, flow modification,
destruction of habitats, invasion by exotic species, pollution including the worldwide phenomena of eutrophication and sedimentation,
all of which are interacting.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens
Freshwater Animal Diversity Assessment 相似文献
11.
The isopod crustaceans are diverse both morphologically and in described species numbers. Nearly 950 described species (∼9%
of all isopods) live in continental waters, and possibly 1,400 species remain undescribed. The high frequency of cryptic species
suggests that these figures are underestimates. Several major freshwater taxa have ancient biogeographic patterns dating from
the division of the continents into Laurasia (Asellidae, Stenasellidae) and Gondwana (Phreatoicidea, Protojaniridae and Heterias). The suborder Asellota has the most described freshwater species, mostly in the families Asellidae and Stenasellidae. The
suborder Phreatoicidea has the largest number of endemic genera. Other primary freshwater taxa have small numbers of described
species, although more species are being discovered, especially in the southern hemisphere. The Oniscidea, although primarily
terrestrial, has a small number of freshwater species. A diverse group of more derived isopods, the ‘Flabellifera’ sensu lato
has regionally important species richness, such as in the Amazon River. These taxa are transitional between marine and freshwater
realms and represent multiple colonisations of continental habitats. Most species of freshwater isopods species and many genera
are narrow range endemics. This endemism ensures that human demand for fresh water will place these isopods at an increasing
risk of extinction, as has already happened in a few documented cases.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens
Freshwater Animal Diversity Assessment 相似文献
12.
A seasonal survey of tardigrade populations in the riparian zone of the Choccolocco Creek, Alabama, was undertaken from August 1994 through December 1995. Six sites within the riparian zone were sampled in different portions of the creek. At each site, 3 trees with cryptogams were sampled six times during survey period. From a total of 108 samples, 1,588 tardigrades were extracted and individually mounted on slides in Hoyer's medium. The community was dominated (86%) by specimens in the genus Macrobiotus. One species of Echiniscus was new to science and will be described in a separate paper. No significant difference was found between tardigrade occurrence (total number of individuals) and season, moss genera, or tree species. However, there was a significant relationship between the number of tardigrades and site, indicating the need for additional replicate samples. Simpson's and Shannon-Wiener's species diversity indices indicated that species richness and evenness were low. Jaccard's and Standard's community similarity indices suggested that the communities within the riparian zone were dissimilar along Choccolocco Creek. 相似文献
13.
The genera Actinopolyspora and Streptomonospora are two groups of extremely halophilic filamentous actinomycetes. Members of these two genera are isolated frequently, probably
due to the high occurrence of these actinomycetes in the hypersaline soil environment. Although members of these genera can
be identified by micromorphological criteria, the extensive chemotaxonomic characterization of each new isolates is a time-consuming
task which cannot always be undertaken when handling large numbers of isolates as is the case in natural products screening
programmes. In this work, the design of one set of genus-specific PCR primers which allows rapid detection of members of the
genus Actinopolyspora by means of PCR amplification is presented. And we developed a multiplex PCR protocol for identification of the species of
the genera Actinopolyspora and Streptomonospora, simultaneously.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
14.
In this study, 137 actinomycetes were isolated from subtidal marine sediments in the North Pacific and Caribbean coasts of
Costa Rica. Bioinformatics analysis of the 16S rRNA gene sequences assigned the isolates to 15 families and 21 genera. Streptomyces was the dominant genus while the remaining 20 genera were poorly represented. Nearly 70% of the phylotypes presented a coastal-restricted
distribution whereas the other 30% were common inhabitants of both shores. The coastal tropical waters of Costa Rica showed
a high diversity of actinomycetes, both in terms of the number of species and phylogenetic composition, although significant
differences were observed between and within shores. The observed pattern of species distribution might be the result of several
factors including the characteristics of the ecosystems, presence of endemic species and the influence of terrestrial runoff.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
16.
The distribution of terrestrial tardigrades in the Gulf Coast states of the United States is poorly known. Only one species
has been reported in Florida. In this study moss, liverwort, lichen and fern samples (47 identified species) from trees and
shrubs were collected from all 67 Florida counties. These samples contained 20 species of tardigrade. All possible pairs of
tardigrade species and tardigrade and substrate were tested for interspecific association. Only three significant negative
and one positive interspecific association between tardigrades were detected. Evidence for substrate specificity was weak.
Although some tardigrade species were significantly associated with mosses or foliose lichens in general, no significant association
between a tardigrade species and a substrate species was detected. 相似文献
17.
How morphological diversity arises through evolution of gene sequence is a major question in biology. In Drosophila, the genetic basis for body patterning and morphological segmentation has been studied intensively. It is clear that some
of the genes in the Drosophila segmentation program are functioning similarly in certain other taxa, although many questions remain about when these gene
functions arose and which taxa use these genes similarly to establish diverse body plans. Tardigrades are an outgroup to arthropods
in the Ecdysozoa and, as such, can provide insight into how gene functions have evolved among the arthropods and their close
relatives. We developed immunostaining methods for tardigrade embryos, and we used cross-reactive antibodies to investigate
the expression of homologs of the pair-rule gene paired (Pax3/7) and the segment polarity gene engrailed in the tardigrade Hypsibius dujardini. We find that in H. dujardini embryos, Pax3/7 protein localizes not in a pair-rule pattern but in a segmentally iterated pattern, after the segments are
established, in regions of the embryo where neurons later arise. Engrailed protein localizes in the posterior ectoderm of
each segment before ectodermal segmentation is apparent. Together with previous results from others, our data support the
conclusions that the pair-rule function of Pax3/7 is specific to the arthropods, that some of the ancient functions of Pax3/7
and Engrailed in ancestral bilaterians may have been in neurogenesis, and that Engrailed may have a function in establishing
morphological boundaries between segments that is conserved at least among the Panarthropoda.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
18.
In the last decades, the number of known tardigrade species has considerably increased to more than 960 species with new ones being discovered every year. However, the study of tardigrade species presents a general problem which is frequently encountered during the work with invertebrates: small size and remarkable degrees of phenotypic plasticity may sometimes not permit a definite identification of the species. In this investigation we have used riboprinting, a tool to study rDNA sequence variation, in order to distinguish tardigrade species from each other. The method combines a restriction site variation approach of ribotyping with amplified DNAs. In eight investigated species of heterotardigrades and eutardigrades we have amplified the genes for the small subunit ribosomal RNA (SSU; 18S) and subsequently sequenced the genes. Virtual riboprints were used for identification of restriction sites from ten already published 18S rDNA sequences and seven new 18S rDNA sequences. On the basis of the obtained sequences, diagnostic restriction fragment patterns can be predicted with only 11 restriction enzymes. The virtual digestion confirmed the obtained restriction fragment patterns and restriction sites of all amplified and digested tardigrade DNAs. We show that the variation in positions and number of restriction sites obtained by standard restriction fragment analysis on agarose gels can be used successfully for taxonomic identification at different taxonomic levels. The simple restriction fragment analysis provides a fast and convenient method of molecular barcoding for species identification in tardigrades. 相似文献
19.
The yeast biodiversity in the guts of several pests ( Diabrotica virgifera, Helicoverpa armigera, Ostrinia nubilalis) on maize from two isolation sources was assessed by cultivation-dependent and cultivation-independent methods. These yeasts
are considered to bear a potentially high biotechnological relevance due to their potential ability to degrade several mycotoxins
incorporated by their hosts. The 97 isolated yeast strains showed 21 different partial sequence types of the 26S rRNA gene
which could be assigned to 10 different genera. The determined genera and species are discussed in terms of the meaning of
their taxonomic status or their occurrence in nature. Two cultivation-independent methods, cloning and DGGE, were compared.
We propose the combination of these methods as well as the combination of both cultivation-independent and cultivation-dependent
approaches, for gaining better insights into fungal biodiversity.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
20.
A cladistic analysis undertaken to test monophyly of Bispira and Stylomma (including new species of both genera) and to ascertain relationships with related taxa reveals that Bispira is paraphyletic without the inclusion of Pseudobranchiomma and Branchiomma, and that Stylomma is monophyletic due to the presence of a structure on the dorsal basal flanges which has never been described before. New
species of Bispira and Stylomma from Australia are described. Bispira serrata n. sp., differs from the other species of the genus in having serrated radiolar flanges whereas all other Bispira species have smooth flanges or lack them, and also by the shape of the thoracic and abdominal uncini, which are short-handled
and have 2–3 rows of big teeth above the main fang, instead of having medium-sized handles and small, numerous rows of teeth
over the main fang. Stylomma juani n. sp., is characterized by the presence of serrated radiolar flanges and unpaired compound eyes along the branchial radioles,
whereas other species in the genus have smooth radiolar flanges and subterminal compound radiolar eyes.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Handling editor: K. Martens 相似文献
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