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1.
Basic hematological parameters of laboratory-reared Lemmus lemmus have been investigated. The results have been summarized together with those from ten other species of microtine rodents. Climatic conditions, especially the microclimate of the subnivean air space, have been considered to offer possible explanations for the higher values in L. trimucronatus compared to L. Lemmus.  相似文献   

2.
Polytomella is a genus of colorless green algae in the Reinhardtinia clade of the Chlamydomonadales, which has proven useful for a broad range of studies particularly those exploring the evolutionary loss of photosynthesis and mitochondrial genomics/biochemistry. Although 13 Polytomella strain accessions are currently available from public culture collections, the taxonomic status and redundancy of many of these strains is not clear because of possible mix‐ups, deficient historical records, and incomplete molecular data. This study therefore considers previously available and/or new cox1 and mitochondrial DNA telomere sequences from all 13 Polytomella strain accessions. Among four of these, namely P. parva SAG 63‐3, P. piriformis SAG 63‐10, P. capuana SAG 63‐5, and P. magna SAG 63‐9, cox1 and mitochondrial telomere regions are both highly divergent between strains. All of the remaining nine Polytomella strain accessions have cox1 sequences that are identical to that of P. parva SAG 63‐3 and although five of these have a mitochondrial telomere haplotype that is identical to that of P. parva SAG 63‐3, the remaining four have one of three different haplotypes. Among the 10 strains with identical cox1 sequences, we suggest that three of the telomere haplotypes are associated with distinct geographical isolates of Polytomella and the fourth evolved from one of these isolates during 50 years of active culture.  相似文献   

3.
In this article, we present the results of morphological study, applying multivariate statistical analysis, of seven samples of recent Lemmini species (Lemmus lemmus, L. sibiricus, Myopus schisricolor) and eight samples of the ancient Siberian lemmings from the Middle and Late Pleistocene localities, mainly in northeastern Europe. On the basis of studying variability of masticatory surface pattern of molars, 24 morphotypes have been described. The differences in morphotypes frequencies were found between the recent Myopus and Lemmus and between the two Norwegian lemming samples. There are some indications of an evolutionary trend in molar morphology of the Siberian lemmings of the Middle, Late Pleistocene, and the recent of Eastern Europe. The distinctions, at least, between the Middle Pleistocene and modern lemmings exceed a species level.  相似文献   

4.
Eugregarines are understudied apicomplexan parasites of invertebrates inhabiting marine, freshwater, and terrestrial environments. Most currently known terrestrial eugregarines have been described parasitizing the gut from less than 1% of total insect diversity, with a high likelihood that the remaining insect species are infected. Eugregarine diversity in orthopterans (grasshoppers, locusts, katydids, and crickets) is still little known. We carried out a survey of the eugregarines parasitizing the Mexican lubber grasshopper, Taeniopoda centurio, an endemic species to the northwest of Mexico. We described two new eugregarine species from the gut of the host: Amoebogregarina taeniopoda n. sp. and Quadruspinospora mexicana n. sp. Both species are morphologically dissimilar in their life‐cycle stages. Our SSU rDNA phylogenetic analysis showed that both species are phylogenetically distant to each other, even though they parasitize the same host. Amoebogregarina taeniopoda n. sp. clustered within the clade Gregarinoidea, being closely related to Amoebogregarina nigra from the grasshopper Melanoplus differentialis. Quadruspinospora mexicana n. sp. clustered within the clade Actinocephaloidea and grouped with Prismatospora evansi, a parasite from dragonfly naiads. Amoebogregarina taeniopoda n. sp. and Q. mexicana n. sp. represent the first record of eugregarines found to infect a species of the family Romaleidae.  相似文献   

5.
6.
Analyses of the mitochondrial cox1, the nuclear‐encoded large subunit (LSU), and the internal transcribed spacer 2 (ITS2) RNA coding region of Pseudo‐nitzschia revealed that the P. pseudodelicatissima complex can be phylogenetically grouped into three distinct clades (Groups I–III), while the P. delicatissima complex forms another distinct clade (Group IV) in both the LSU and ITS2 phylogenetic trees. It was elucidated that comprehensive taxon sampling (sampling of sequences), selection of appropriate target genes and outgroup, and alignment strategies influenced the phylogenetic accuracy. Based on the genetic divergence, ITS2 resulted in the most resolved trees, followed by cox1 and LSU. The morphological characters available for Pseudo‐nitzschia, although limited in number, were overall in agreement with the phylogenies when mapped onto the ITS2 tree. Information on the presence/absence of a central nodule, number of rows of poroids in each stria, and of sectors dividing the poroids mapped onto the ITS2 tree revealed the evolution of the recently diverged species. The morphologically based species complexes showed evolutionary relevance in agreement with molecular phylogeny inferred from ITS2 sequence–structure data. The data set of the hypervariable region of ITS2 improved the phylogenetic inference compared to the cox1 and LSU data sets. The taxonomic status of P. cuspidata and P. pseudodelicatissima requires further elucidation.  相似文献   

7.
Members of the family Brachionidae are free-living organisms that range in size from 170 to 250 microns. They comprise part of the zooplankton in freshwater and marine systems worldwide. Morphologically, members of the family are characterized by a single piece loricated body without furrows, grooves, sulci or dorsal head shields, and a malleate trophi. Differences in these structures have been traditionally used to recognize 217 species that are classified into seven genera. However, the validity of the species, Plationus patulus, P. patulus macracanthus P. polyacanthus, and P. felicitas have been confused because they were alternatively assigned in Brachionus or Platyias, when considering only morphological and ecological characters. Based on scanning electron microscope (SEM) images of the trophi, these taxa were assigned in a new genus, Plationus. In this study, we examined the systematic position of P. patulus and P. patulus macracanthus using DNA sequences of two genes: the cytochrome oxidase subunit 1 (cox1) and domains D2 and D3 of the large subunit of the nuclear ribosomal RNA (LSU). In addition, the cox1 and LSU sequences representing five genera of Brachionidae (Anuraeopsis, Brachionus, Keratella, Plationus, and Platyias) plus four species of three families from the order Ploima were used as the outgroup. The maximum likelihood (ML) analyses were conducted for each individual gene as well as for the combined (cox1 + LSU) data set. The ML tree from the combined data set yielded the family Brachionidae as a monophyletic group with weak bootstrap support (<50%). Five main clades in this tree had high (>85%) bootstrap support. The first clade was composed of three populations of P. patulus + P. patulus macracanthus. The second clade was composed of a single species of Platyias. The third clade was composed of six species of Brachionus. The fourth clade included a single species of the genus Anuraeopsis, and the fifth clade was composed of three species of the genus Keratella. The genetic divergence between Plationus and Platyias ranged from 18.4 to 19.2% for cox1, and from 4.5 to 4.9% for LSU, and between Brachionus and Plationus, it ranged from 16.9 to 23.1% (cox1), and from 7.3 to 9.1% (LSU). Morphological evidence, the amount of genetic divergence, the systematic position of Plationus within the family Brachionidae, and the position of Plationus as a sister group of Brachionus and Platyias support the validity of Plationus patulus and P. patulus macracanthus into the genus Plationus.  相似文献   

8.
Members of Calamyzinae, a clade of free‐living and ectoparasitic chrysopetalids, are mainly associated with deep‐sea chemosynthetic environments. The three currently known free‐living calamyzin species are placed in Vigtorniella. A new free‐living calamyzin species similar to these is described here. Phylogenetic analyses of Calamyzinae using mitochondrial (cytochrome c oxidase subunit I and 16S rDNA) and nuclear (Histone H3 and 18S rDNA) loci showed that Vigtorniella and the new species form a grade with respect to an ectoparasitic clade, requiring two new genera to be erected. All free‐living calamyzins show a similar anterior end and chaetal morphology. Micospina auribohnorum gen. et sp. nov. is described for the small‐bodied new species from deep‐sea whale falls off California and methane seeps off Costa Rica. The maximum‐likelihood and Bayesian analyses show Micospina gen. nov. as sister to the ectoparasitic clade. Boudemos gen. nov. is named for the clade of two larger‐bodied species: Boudemos flokati gen. et comb. nov. and Boudemos ardabilia gen. et comb. nov., which is sister group to all other Calamyzinae. Vigtorniella is retained for the type species, Vigtorniella zaikai (Kiseleva, 1992), with the adults found amongst bacterial mats at the boundary of the hydrogen sulphide zone in the Black Sea. Micospina gen. nov., Boudemos gen. nov., and Vigtorniella form a grade of free‐living taxa that is associated with feeding on organic‐enriched sediments, and the latter two taxa display ontogenetic jaw change. Jaws are absent in Micospina auribohnorum gen. et sp. nov. and most of the calamyzin clade of parasitic forms.  相似文献   

9.
The identification of species within the genus Tetrahymena is known to be difficult due to their essentially identical morphology, the occurrence of cryptic and sibling species and the phenotypic plasticity associated with the polymorphic life cycle of some species. We have combined morphology and molecular biology to describe Tetrahymena aquasubterranea n. sp. from groundwater of Cape Town, Republic of South Africa. The phylogenetic analysis compares the cox1 gene sequence of T. aquasubterranea with the cox1 gene sequences of other Tetrahymena species and uses the interior‐branch test to improve the resolution of the evolutionary relationships. This showed a considerable genetic divergence of T. aquasubterranea to its next relative, T. farlyi, of 9.2% (the average cox1 divergence among bona fide species of Tetrahymena is ~ 10%). Moreover, the analysis also suggested a sister relationship between T. aquasubterranea and a big clade comprising T. farleyi, T. tropicalis, T. furgasoni and T. mobilis. The morphological data available for these species show that they share with T. aquasubterranea a pyriformis‐like life style and at least two of them, T. farleyi and T. mobilis, a similar type II silverline pattern consisting of primary and secondary meridians. Tetrahymena aquasubterranea exhibits a biphasic life cycle with trophonts and theronts, is amicronucleate, and feeds on bacteria.  相似文献   

10.
Recent study on Lasiopodomys (Stenocranius) gregalis has revealed four clear mitochondrial lineages with differences exceeding the species level. The most divergent is the clade from south‐eastern Transbaikalia. Multilocus (six nuclear genes), morphological (dental characters of m1 and M3) and behavioural (breeding experiments) analyses were conducted to test the hypothesis that L. gregalis is a complex of two cryptic species. All of the applied methods distinguish the independent status of voles from south‐eastern Transbaikalia. This clade occupies a portion of the distribution range of the currently valid subspecies L. g. raddei including its terra typica. According to the results of cyt b analysis, the lectotype of L. g. raddei belongs to the Transbaikal clade. We re‐establish the species status for the taxon Lasiopodomys raddei including populations from south‐eastern Transbaikalia, as a cryptic species of the narrow‐headed vole complex.  相似文献   

11.
A new freshwater species of naked lobose amoebae Korotnevella venosa n. sp. isolated from freshwater pond in St. Petersburg, Russia was studied with light and transmission electron microscopy. Basket scales of this species have six vertical columns supporting perforated rim. The latter has tongue‐like broadening with membranous region. Vertical columns bifurcate at both ends so that neighboring columns are connected by their bifurcations forming combined structure. Basket scales of K. venosa are similar to those of Korotnevella hemistylolepis in having six full‐length vertical columns and perforated rim. At the same time, they are different in having tongue‐like broadening of perforated rim with membranous region and absence of six half‐length columns and an intermediate crosspiece. Phylogenetic trees based on 18S rDNA gene placed K. venosa either at the base of the whole Korotnevella clade, next to K. hemistylolepis, or as a sister to the clade comprising Korotnevella species with latticework basket in large scales.  相似文献   

12.
Sponges are the dominant invertebrates in many Antarctic communities, where they play a decisive structural function thanks to their abundance and large sizes. However, current knowledge on Antarctic sponges remains poor even with respect to basic aspects such as taxonomy. Here, we report on an Antarctic species of the genus Stylocordyla, which has been recorded for a long time under the name of the boreal S. borealis due to spicule and growth habit similarities. A thorough study of dense populations of the only Stylocordyla species known up to now from the eastern zone of the Weddell Sea as well as the re-examination of several specimens (including the type material) of S. borealis has allowed us to assess the variability of the boreal species and to confirm that the austral species is not S. borealis (Lovén, 1868) but a new species of Stylocordyla, different from the other congeners recorded from southern latitudes. The new species S. chupachups commonly dwells on horizontal or slighted sloped hard bottoms of the continental shelf of Weddell Sea, from 100 m to below 400 m depth, although the densest populations usually occur between 150 and 300 m. It is a pioneer species in areas that have been scoured by icebergs, and thus its presence may be considered an indicator of recent colonisation.  相似文献   

13.
The bot fly Gruninomyia mira Szpila & Pape, gen.n. , sp.n. is described from Iran, North Khorasan, based on a single adult male and with no larval or host data. The monotypic genus shows a mixture of features otherwise found in either the rodent/lagomorph‐parasitizing oestromyine clade (Oestroderma + Oestromyia) or the artiodactyl‐parasitizing hypodermatine clade (Hypoderma + Pallasiomyia + Pavlovskiata + Przhevalskiana + Strobiloestrus) of subfamily Hypodermatinae. A morphology‐based phylogenetic analysis is marginally in favour of a position of Gruninomyia Szpila & Pape, gen.n. as sister taxon of (Oestroderma + Oestromyia). The COI barcode sequence is provided for the new species, and a phylogenetic analysis based on this marker for Oestridae retrieved from GenBank is in agreement with the conclusions based on morphological data. This published work has been registered in ZooBank: http://zoobank.org/urn:lsid:zoobank.org:pub:8F0CBE07‐4E74‐4186‐B690‐2C97D7ED7DA7 .  相似文献   

14.
15.
In an effort to broaden our understanding of the biodiversity and distribution of gregarines infecting crustaceans, this study describes two new species of gregarines, Thiriotia hyperdolphinae n. sp. and Cephaloidophora oradareae n. sp., parasitizing a deep sea amphipod (Oradarea sp.). Amphipods were collected using the ROV Hyper‐Dolphin at a depth of 855 m while on a cruise in Sagami Bay, Japan. Gregarine trophozoites and gamonts were isolated from the gut of the amphipod and studied with light and scanning electron microscopy, and phylogenetic analysis of 18S rDNA. Thiriotia hyperdolphinae n. sp. was distinguished from existing species based on morphology, phylogenetic position, as well as host niche and geographic locality. Cephaloidophora oradareae n. sp. distinguished itself from existing Cephaloidophora, based on a difference in host (Oradarea sp.), geographic location, and to a certain extent morphology. We established this latter new species with the understanding that a more comprehensive examination of diversity at the molecular level is necessary within Cephaloidophora. Results from the 18S rDNA molecular phylogeny showed that T. hyperdolphinae n. sp. was positioned within a clade consisting of Thiriotia spp., while C. oradareae n. sp. grouped within the Cephaloidophoridae. Still, supplemental genetic information from gregarines infecting crustaceans will be needed to better understand relationships within this group of apicomplexans.  相似文献   

16.
A phylogenetic (cladistic) analysis was conducted for 15 ancyrocephalid (Monogenea) species parasitizing North American freshwater fishes. The analysis was based on 10 (four binary and six multistate) characters. Vaginal characters were not included due to insufficient data. The resultant, most parsimonious cladogram was 38 steps long with a consistency index of 0.921: reduced consistency was attributed to two cases of homoplasy and one reversal. Three unresolved polychotomies were observed. Three clades were recognized: clade 1 — Actinocleidus species; clade 2 — Anchoradiscoides, Anchoradiscus, Clavunculus species and Syncleithrium; and clade 3 — Crinicleidus species. The protocol for and implications of character identification and polarisation and the establishment of transformation series were discussed.  相似文献   

17.
Natural populations of Zygnema were collected from 80 stream sites across California, and eight species were identified and characterized morphologically. Generic and infrageneric concepts of Zygnema and Zygogonium were tested with cox3 and rbcL gene sequence analysis. Strains of Zygnema were positioned in a single monophyletic clade sister to Zygogonium tunetanum Gauth.‐Lièvre. In both the rbcL and cox3 phylogenies, strains of Zygnema formed two major clades. The first clade contained species that have zygospores with a blue‐colored mesospore or akinetes with a colorless mesospore. The second clade contained species that have a yellow or brown mesospore. The existing taxonomic concepts for Zygnema classification are not consistent with our molecular phylogeny and do not correspond to natural groups. We propose that mesospore color may be useful in the infrageneric classification of Zygnema. Newly described Zygnema aplanosporum sp. nov. and Zygnema californicum sp. nov. have zygospores with a blue mesospore formed in the conjugation tube and separated by a cellulosic sporangial wall. Z. aplanosporum also possessed a combination of vegetative and reproductive features characteristic of Zygogonium, such as presence of short branches, rhizoidal outgrowths, thickened vegetative cell walls, purple‐colored cell content, small compressed‐globular chloroplasts as well as predominant asexual reproduction. Z. aplanosporum and Z. californicum were deeply embedded in a larger clade of Zygnema both in rbcL and cox3 analyses. Based on our observations, there are no features or combination of features that separate Zygnema and Zygogonium. Therefore, we conclude that Zygogonium is probably a synonym of Zygnema.  相似文献   

18.
Less than 1% of Staphylinidae are known to be confined to coastal habitats. To explore the origins of coastal colonization within the tribe Athetini Casey, we present a revised molecular phylogeny. The dataset comprised partial mitochondrial COI, COII, 16S rDNA, NADH1, partial nuclear 18S rDNA and 28S rDNA. We chose a total of 95 species in 51 genera, including 14 coastal species in eight genera and 21 outgroup species from other aleocharine tribes. The concatenated dataset was analysed simultaneously by both parsimony‐ and model‐based (Bayesian and maximum likelihood) methods. The tribe Athetini was not supported as a monophyletic group, but together with the tribes Tachyusini, Ecitocharini and Hygronomini did form a monophylum. The ecological association of species with a coastal habitat was mapped onto a phylogeny to assess the evolution of habitat specialization in the Athetini lineage. The results reveal that five independent origins of coastal colonization have occurred throughout the tribe Athetini: (a) Osakatheta + Adota minuta + coastal Atheta (Badura) (clade A); (b) Adota (clade B); (c) Pontomalota + Tarphiota + Thinusa (clade C); (d) Iotarphia (clade D); and (e) Psammostiba (clade E). The low species number of the coastal Athetini compared with the entire Athetini lineage indicates that coastal habitats are harsh environments and so only a few species were able to colonize this habitat. The following changes in classification are proposed: (a) Ad. minuta Lee and Ahn is removed from the genus Adota and tentatively included in Atheta (Badura); (b) The genus Saphocallus Sharp is transferred from Athetini to Geostibini.  相似文献   

19.
The subfamily Crucigenioideae was traditionally classified within the well‐characterized family Scenedesmaceae (Chlorophyceae). Several morpho‐logical revisions and questionable taxonomic changes hampered the correct classification of crucigenoid species resulting in a high number of synonymous genera. We used a molecular approach to determine the phylogenetic position of several Tetrastrum and Crucigenia species. The molecular results were correlated with morphological and ontogenetic characters. Phylogenetic analyses of the SSU rDNA gene resolved the position of Tetrastrum heteracanthum and T. staurogeniaeforme as a new lineage within the Oocystis clade of the Trebouxiophyceae. Crucigenia tetrapedia, T. triangulare, T. punctatum, and T. komarekii were shown to be closely related to Botryococcus (Trebouxiophyceae) and were transferred to Lemmer‐mannia. Crucigenia lauterbornii was not closely related to the other Crucigenia strains, but was recovered within the Chlorella clade of the Trebouxiophyceae.  相似文献   

20.
The diversity of the freshwater-fish genus Rasbora (Cyprinidae) on Sri Lanka (five species) is high compared with the four species reported from the peninsula of India, from which the island's cyprinid fauna is derived. The paucity of characters by which species of Rasbora can be phenotypically distinguished renders field identification difficult, adversely affecting the estimation of populations and distributions, with consequences for conservation and management, increasing also the risk of taxonomic inflation. From a sampling of 90 sites across Sri Lanka and based on phylogenetic and haplotype analyses of sequences of cox1 and cytb mitochondrial, and rag1 and irbp nuclear markers, we review the species diversity and phylogeography of Rasbora on the island. Molecular analyses recover, in addition to the five species previously reported, a new (cryptic) species: Rasbora adisi sp. nov. Uncorrected pairwise cox1 genetic distances between species range from 2.0 to 12.3 percent. The Sri Lankan diversification derives from a common ancestor which arrived from India during a sea-level low-stand in the mid-Miocene (15.1 Ma [95% HPD: 11.5–19.8 Ma]), when the present-day island was subaerially connected to the Indian subcontinent by a broad isthmus. This gave rise to a clade comprising five species—R. adisi sp. nov.,Rasbora armitagei, Rasbora microcephalus, Rasbora naggsi and Rasbora wilpita—with a crown age of 9.9 Ma (95% HPD: 7.1–13.3 Ma) and to a clade comprising Indian and Sri Lankan populations of Rasbora dandia, which themselves are reciprocally monophyletic. Morphological analysis of 334 specimens discriminates between most species which, however, are most reliably diagnosed by chromatic characters. The four endemic species exhibit a pattern of inter-basin dispersal via headwater capture, followed by vicariance, explaining the high diversity of the genus on the island.  相似文献   

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