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1.
Paranoplocephala etholeni n. sp., parasitizing the meadow vole Microtus pennsylvanicus in Alaska and Wisconsin, USA, is described. Paranoplocephala etholeni is morphologically most closely related to the Nearctic Paranoplocephala ondatrae (Rausch, 1948). Available data suggest that P. etholeni is a host-specific, locally rare species that may have a wide but sporadic geographical distribution in North America. The finding of P. ondatrae-like cestodes in Microtus spp. suggests that this poorly known species may actually be a parasite of voles rather than muskrat (type host). A tabular synopsis of all the known species of Paranoplocephala s. l. in the Holarctic region with their main morphological features is presented.  相似文献   

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Aim  Pleistocene climatic cycles have left marked signatures in the spatial and historical genetic structure of high‐latitude organisms. We examine the mitochondrial (cytochrome b) genetic structure of the singing vole, Microtus miurus (Rodentia: Cricetidae: Arvicolinae), a member of the Pleistocene Beringian fauna, and of the insular vole, Microtus abbreviatus, its putative sister species found only on the St Matthew Archipelago. We reconstruct the phylogenetic and phylogeographical structure of these taxa, characterize their geographical partitioning and date coalescent and cladogenetic events in these species. Finally, we compare the recovered results with the phylogenetic, coalescent and spatial genetic patterns of other eastern Beringian mammals and high‐latitude arvicoline rodents. Location  Continental Alaska (alpine and arctic tundra) and the St Matthew Archipelago (Bering Sea). Methods  We generated and analysed cytochrome b sequences of 97 singing and insular voles (M. miurus and M. abbreviatus) from Alaska. Deep evolutionary structure was inferred by phylogenetic analysis using parsimony, maximum likelihood and Bayesian approaches; the geographical structure of genetic diversity was assessed using analysis of molecular variance and network analysis; ages of cladogenetic and coalescent events were estimated using a relaxed molecular clock model with Bayesian approximation. Results  Regional nucleotide diversity in singing voles is higher than in other high‐latitude arvicoline species, but intra‐population diversity is within the observed range of values for arvicolines. Microtus abbreviatus specimens are phylogenetically nested within M. miurus. Molecular divergence date estimates indicate that current genetic diversity was formed in the last glacial (Wisconsinan) and previous interglacial (Sangamonian) periods, with the exception of a Middle Pleistocene split found between samples collected in the Wrangell Mountains region and all other singing vole samples. Main conclusions  High levels of phylogenetic and spatial structure are observed among analysed populations. This pattern is consistent with that expected for a taxon with a long history in Beringia. The spatial genetic structure of continental singing voles differs in its northern and southern ranges, possibly reflecting differences in habitat distribution between arctic and alpine tundra. Our phylogenetic results support the taxonomic inclusion of M. miurus in its senior synonym, M. abbreviatus.  相似文献   

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We describe Paranoplocephala yoccozi n. sp. (Cestoda: Anoplocephalidae) from the snow vole Chionomys nivalis in Bourg-Saint-Maurice, French Alps, compare it with several related species from rodents, and review the anoplocephalid cestodes of snow voles in Europe. Paranoplocephala yoccozi n. sp. is primarily distinguished from the related species by its large scolex of characteristic shape, robust neck region, and the structure of the cirrus sac, vitellarium and vagina. We show that the anoplocephalid cestodes of snow voles in Europe, representing the genera Anoplocephaloides and Paranoplocephala, include at least seven species. This fauna consists primarily of species that snow voles share with other voles inhabiting the high-mountain areas. Some of the species, including P. yoccozi n. sp., appear to have a very localized distribution, which is assumed to be a consequence of the historical fragmentation of snow vole populations.  相似文献   

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Aim   To examine the issue of Beringian steppe-tundra from an entomological standpoint, using fossil beetle data collected from late Pleistocene sites.
Location   North-eastern Siberia (Western Beringia), the Bering Land Bridge (Central Beringia), and Alaska and the Yukon Territory (Eastern Beringia).
Methods   Analysis of habitat preferences of beetle species found in fossil assemblages, leading to classification of major habitat types characterized by the faunal assemblages.
Results   Fossil beetle assemblages indicative of steppe-tundra are found mainly in the interior regions of Eastern Beringia, whereas these assemblages dominate nearly all late Pleistocene fossil sites in Western Beringia. Eastern Beringian faunas contain a much larger proportion of mesic to hygrophilous species and very few arid-habitat species. In contrast to this, the habitat requirements of the Western Beringian faunas are more evenly spread across the moisture spectrum.
Main conclusions   The taxonomic patterns of the two sets of fossil assemblages are remarkably different. Eastern Beringian faunal assemblages contain substantial numbers of mesic tundra and riparian rove beetles (Staphylinidae); this element is almost entirely lacking in the Western Beringian fossil assemblages. Taphonomic bias tends to overemphasize moisture-loving species at the expense of dry, upland species in the fossil record. Both Western and Eastern Beringian landscapes undoubtedly contained mosaics of habitats ranging from dry uplands (steppe-tundra) through mesic tundra to bogs and riparian corridors.  相似文献   

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In this study we revise the cheilostome bryozoan genus Buffonellaria Canu & Bassler, 1927 and its Mediterranean and north-east Atlantic species, thereby addressing several existing problems. First, a lectotype for the type species, Buffonellaria divergens (Smitt, 1873) from Florida, is chosen, which proves to be distinct from the European species. Second, the two hitherto established north-east Atlantic species [ Buffonellaria nebulosa ( Jullien & Calvet, 1903 ) and Buffonellaria porcellanum Arístegui Ruiz, 1987], are redescribed, which were poorly documented until now. Third, close inspection of material, collected from Spitsbergen to tropical West Africa, using scanning electron microscopy reveals that the actual number of species, all previously referred to either B. divergens or Stephanosella biaperta (Michelin, 1848), is distinctly greater in the north-east Atlantic than has been previously acknowledged. As a result, seven new species are introduced ( Buffonellaria acorensis sp. nov. , Buffonellaria antoniettae sp. nov. , Buffonellaria arctica sp. nov. , Buffonellaria harmelini sp. nov. , Buffonellaria jensi sp. nov. , Buffonellaria muriella sp. nov. , and Buffonellaria ritae sp. nov. ), whereas two are left in open nomenclature. With the increase in number of species, the extremely broad geographical range of distribution assumed for B. divergens breaks down to numerous restricted areas. However, although most species have only been reported from a single location, B. arctica sp. nov. seems to have a fairly wide distribution in the Arctic region.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 152 , 537–566.  相似文献   

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Diet differentiation between European arvicoline and murine rodents   总被引:1,自引:0,他引:1  
Small European muroid rodents are generally divided into species which feed on seeds and/or invertebrates and species which feed on green plant material; however, there is considerable plasticity in feeding behavior among species. Here, we analyze diets of 14 low-latitude rodent species from Western Europe based on published studies. The 77 studies were submitted to principal component analysis in order to compare diet plasticity within and between the 14 species. We observed variations in food composition of arvicoline and murine rodents which are associated with differences in morphology and habitat use. Most arvicoline rodents eat mainly green matter of the herbaceous layers of open habitats whereas most murine species are able to use a greater diversity of high energetic plant tissues from denser habitats, where they can exploit the different vegetation layers. Despite its phylogenetic position among arvicoline rodents, the bank vole (Myodes glareolus) shows morpho-physiological and ecological traits which tend to be more similar to murine species. These intermediate evolutionary characters seem consistent with the fact that bank voles are able to exploit a wide spectrum of trophic resources from low energetic lignified tissues to high calorific invertebrate prey. This results in a very diverse diet, which is intermediate between true herbivorous arvicolines and typical seed- and invertebrate-eating murine species. More investigations on genetic affiliation and ecological driving forces will help understand this intermediate position of bank vole diet, and further investigations among other arvicoline species will help determine if bank voles and other Myodes species are unique.  相似文献   

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Phylogeography of Soboliphyme baturini , a nematode parasite in mustelids, is explored across Beringia. Sequences of the mitochondrial cytochrome c oxidase subunit I and nicotinamide adenine dinucleotide dehydrogenase subunit 4 genes were evaluated from 37 S. baturini , representing 19 localities throughout Alaska, Canada, and Siberia. A total of 30 haplotypes was recovered and maximum parsimony and Bayesian phylogenetic analyses support the recognition of a single species with a distribution extending from the Palearctic to the Nearctic. Within S. baturini , a host-specific partition in North America between Martes caurina and Martes americana was not identified. Instead, substantial geographic structure within S. baturini relates to the dynamic geological history of this northern region and especially the North Pacific Coast. Beringia and other coastal refugia along the western margin of North America played a large role during stadial maxima in the persistence and divergence of the parasite. Repeated events for biotic expansion and geographic colonization across the Bering Land Bridge and the Holarctic during glacial maxima in the Pleistocene appear to have facilitated at least two episodes of host-switching of this nematode among mustelids in populations now distributed in eastern Beringia.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 651–663.  相似文献   

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Natural hybridization between species is not a rare event. In arvicoline rodents, hybridization is known to occur in the wild and/or in captivity. In the Microtus arvalis group, cytogenetic studies revealed that there were two distinct chromosomal forms (2n = 46 but a different fundamental number of autosomes). These forms have been attributed to two cryptic species: the common (arvalis) and Altai (obscurus) voles. Recently, individuals with intermediate karyotypes (F1 and backcrosses) were discovered in central European Russia, and, for this reason, other studies have regarded obscurus and arvalis as conspecific. In the present study, to address the question of the species limits in the Altai vole and to infer its evolutionary history, a phylogeographical analysis combined with multivariate morphometric methods and original chromosome data was performed. Two obscurus lineages were identified: the Sino‐Russian and South Caucasian lineages. Both lineages are characterized by low genetic diversity, resulting, in the former, from a past bottleneck event caused by encroaching periglacial areas and, in the latter, from recent rapid population divergence. Introgressive hybridization between the Altai and common voles appears to be the result of a secondary contact following the Last Glacial Maximum in central European Russia. Despite the fact that speciation is an ongoing process in most arvicoline species, the common and Altai voles are genetically divergent, morphologically and karyologically distinct, and exhibit contrasting evolutionary histories. For all these reasons, they should be ranked as species: M. arvalis and M. obscurus. © 2013 The Linnean Society of London  相似文献   

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We describe the gastrointestinal helminth fauna of true lemmings (Lemmus spp., Arvicolinae) based on published and original material throughout the Holarctic range of these hosts. According to the existing data, the helminth fauna of true lemmings consists of three widespread and/or locally common taxa: Hymenolepis horrida (sensu lato) (Hymenolepididae), Anoplocephaloides lemmi (Anoplocephalidae) and Heligmosomoides spp. (Heligmosomidae). Despite the taxonomic boundaries and ancient phylogenetic splits in the hosts, there are no major faunistic differences for parasites within western (Siberian) L. sibiricus and L. bungei, and eastern (North American) L. trimucronatus throughout their distribution range. In contrast, the Norwegian lemming L. lemmus, which is a Fennoscandian endemic and closely related to the western populations of L. sibiricus, has only a single host-specific helminth, the cestode Paranoplocephala fellmani n. sp. (Anoplocephalidae). We describe the new species and show that it differs consistently from related species by its long and slender cirrus-sac. However, there are also a number of other significant differences, e.g., P. fellmani n. sp. and Andrya primordialis in Tamiasciurus hudsonicus (Sciuridae) evidently have a unique (sub)type of uterine development among Andrya/Paranoplocephala spp. Because P. fellmani n. sp. was also found to occur in Alaska (host L. trimucronatus), this species seems to follow the same biogeographical pattern as the other specialist helminths of Lemmus. We suggest alternative explanations for the absence of three major helminth taxa in the Norwegian lemming in Fennoscandia.  相似文献   

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Arctic warbler Phylloscopus borealis is one of several high‐latitude Passerines which are widely distributed across one northern continent but restricted to the Beringian part of the other. Most species with such asymmetric intercontinental ranges are monomorphic across Beringia, suggesting either recent colonization of the second continent or considerable gene flow across the Bering Strait. Arctic warbler is the only migratory species in this group that has three different subspecies in Beringia: Ph. b. borealis (Scandinavia to western Beringia, south to Mongolia), Ph. b. xanthodryas (Japan, Sakhalin, Kamchatka, western Beringia), and Ph. b. kennicotti (Alaska). This polymorphism may indicate that Arctic warbler has a unique and complex phylogeographic history that differs significantly from other species with similar ranges. Our analyses of complete mtDNA ND2 sequences of 88 Arctic warblers collected across the species range showed that the clade comprised of birds breeding on Sakhalin Island and Kamchatka Peninsula diverged from the Palearctic/Beringian clade by 3.8% in ND2 sequence. Beringian birds formed a recently derived clade embedded within the Palearctic clade. Nucleotide diversity declined sharply eastward from Palearctic to western Beringia and then to eastern Beringia. Our data provided no support for currently recognized subspecies. They suggested that the barrier at the western edge of Beringia was crossed by Arctic warbler earlier than the Bering Strait resulting in a stepping‐stone colonization of Beringia by this species. Gene flow appears to be restricted across the western border of Beringia but not the Bering Strait.  相似文献   

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Repeated glacial events during the Pleistocene fragmented and displaced populations throughout the northern continents. Different models of the effects of these climate-driven events predict distinct phylogeographic and population genetic outcomes for high-latitude faunas. The role of glaciations in (i) promoting intraspecific genetic differentiation and (ii) influencing genetic diversity was tested within a phylogeographic framework using the rodent Microtus oeconomus. The spatial focus for the study was Beringia, which spans eastern Siberia and northwestern North America, and was a continental crossroads and potential high arctic refugium during glaciations. Variation in mitochondrial DNA (cytochrome b and control region; 214 individuals) and nuclear DNA (ALDH1 intron; 63 individuals) was investigated across the Beringian region. Close genetic relationships among populations on either side of the Bering Strait are consistent with a history of periodic land connections between North America and Asia. A genetic discontinuity observed in western Beringia between members of a Central Asian clade and a Beringian clade is geographically congruent with glacial advances and with phylogeographic discontinuities identified in other organisms. Divergent island populations in southern Alaska were probably initially isolated by glacial vicariance, but subsequent differentiation has resulted from insularity. Tests of the genetic effects of postglacial colonization were largely consistent with expansion accompanied by founder effect bottlenecking, which yields reduced diversity in populations from recently deglaciated areas. Evidence that populations in the Beringian clade share a history of expansion from a low-diversity ancestral population suggests that Beringia was colonized by a small founder population from central Asia, which subsequently expanded in isolation.  相似文献   

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A diverse, new lizard assemblage from the early Oligocene of Belgium is described. The Boutersem railway local fauna is the most species‐rich lizard assemblage yet reported from the European early Oligocene. Four lizard taxa are present: Lacertidae, Anguidae, Scincoidea and Platynota. One new species is described, Folisaurus boutersemensis sp. nov . This fauna provides new insight into the profound turnover that took place during the Eocene/Oligocene boundary in Europe. The new fauna confirms a marked decrease in diversity across the Eocene/Oligocene boundary. Two groups encountered in the European late Eocene became extinct (Iguanidae*, Glyptosaurinae). Estimates of species‐level extinctions range up to 80%. These estimates include members of virtually all the families present in the late Eocene. The relative importance of climate change and biotic interactions in controlling this pattern is discussed, and negative interactions between lizards and new carnivorous mammals are favoured. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 148–170.  相似文献   

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A species-wide phylogeographical study of the root vole (Microtus oeconomus) was performed using the whole 1140 base pair mitochondrial (mt) cytochrome b gene. We examined 83 specimens from 52 localities resulting in 65 unique haplotypes. Our results demonstrate that the root vole is divided into four main mtDNA phylogenetic lineages that seem to have largely allopatric distributions. Net divergence estimates (2.0-3.5%) between phylogroups, as well as relatively high nucleotide diversity estimates within phylogroups, indicate that the distinct phylogeographical structure was initiated by historical events that predated the latest glaciation. European root voles are divided into a Northern and a Central mtDNA phylogroup. The mtDNA data in concert with fossil records imply that root voles remained north of the classical refugial areas in southern Europe during the last glacial period. The currently fragmented populations in central Europe belong to a single mtDNA phylogroup. The Central Asian and the North European lineages are separated by the Ural Mountains, a phylogeographical split also found in collared lemmings (Dicrostonyx) and the common vole (M. arvalis). The Beringian lineage occurs from eastern Russia through Alaska to northwestern Canada. This distribution is congruent with the traditional boundaries of the Beringian refugium and with phylogeographical work on other organisms. In conclusion, similarities between the phylogeographical patterns in the root vole and other rodents, such as Arctic and subarctic lemmings, as well as more temperate vole species, indicate that late Quaternary geological and climatic events played a strong role in structuring northern biotic communities.  相似文献   

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Abstract. The mountain midges (Diptera: Deuterophlebiidae) of the Palaearctic Region are revised to include eight species. Four new species are described: D. brachyrhina sp. nov., D.oporina sp. nov. and D. blepharis sp.nov. from the Himalayas (Assam and Sikkim), and D.bicarinata sp. nov. from southern Korea. A lectotype is designated for D.mirabilis Edwards, and a key to adult males of all Palaearctic species is provided.
Larval, pupal and adult characters were used to reconstruct the phylogenetic and biogeographic relationships of world species of Deuterophlebiidae. Based on features of the adult male, the Himalayan species D. brachyrhina and D. oporina are considered the most primitive deuterophlebiids. The Nearctic species D. inyoensis is proposed as the sister group of the remaining species. Relationships among the latter are based primarily on larval and pupal characters; however, lack of information about the immature stages of several Palaearctic species contributes to a poorly resolved phylogeny. Several alternative hypotheses are presented and discussed. All phylogenetic alternatives suggest that the Nearctic fauna originated from at least two invasions of North America.  相似文献   

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A range‐wide phylogeographic study of the tundra shrew (Sorex tundrensis) was performed using cytochrome b and cytochrome oxidase I (COI) mitochondrial genes. The results based on 121 specimens from 42 localities demonstrate that the tundra shrew is divided into five main mitochondrial DNA phylogenetic lineages with largely parapatric distribution. In addition to a single Nearctic clade (Alaska) four Palearctic clades are identified: Western (Northen Urals, Kazakhstan, South‐West Siberia), Eastern (from East Transbaikalia and the Middle Amur to Chukotka), South Central (Central Siberia, the Altai, the Dzhungarian Alatau) and North Central (Northern Siberia, Central Yakutia). Date estimates obtained by use of a molecular clock corrected for potential rate decay suggest Late Pleistocene age for the most recent common ancestor of all contemporary tundra shrew populations. Relatively high genetic divergence between phylogroups (0.95–1.6%) indicates that the observed phylogeographic structure was initiated by historical events that predated the Last Glacial Maximum. We assume that, being more cold‐ and arid‐tolerant, tundra shrew underwent expansion during an early cold phase of the Last Glacial and spread through its recent range earlier than most of other Siberian red‐toothed shrews. Comparative phylogeographic analysis of Siberian shrews and rodents suggests that evolutionary histories of species associated with azonal or open habitats show important differences compared to forest species. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 721–746.  相似文献   

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Abstract. The world species of anthomyiid cone and seed pests are revised. A new genus, Strobilomyia gen.n., is erected for the eighteen species, including seven new to science, presently recognized. Author's views on homologies in the male and female terminalia of Anthomyiidae and other Diptera Cyclorrhapha are amplified as background for the terminology employed. The monophyly and systematic position of Strobilomyia are discussed with reassessions of related genera: Lasiomma Stein, Chirosia Rondani, Egle Robineau-Desvoidy and Acklandia Hennig. Zoogeographic aspects, especially vicariance across the Beringia, are analysed from a partial hypothesis of phylogenetic relationships among the species of Strobilomyia in conjunction with paleo-environmental data. New generic synonyms are: Macrophorbia Malloch, Crinurina Karl, Si-nohylemya Hsue (all =Lasiomma); Acrostilpna Ringdahl, Shakshainia Suwa, Meliniella Suwa (all =Chirosia). The species recognized in Strobilomyia (with geographic range and host trees in parentheses) are: anthracina (Czerny) (Palearctic, Picea); neanthracina sp.n. (Nearctic, Picea and ITsuga); appalachensis sp.n. (E. Nearctic); melania (Ackland) (Europe, Larix); sibirica sp.n. (N.E. Europe, Siberia, Larix); viaria (Huckett) (E. Palearctic, Nearctic, Larix); infrequens (Ackland) (Palearctic, Larix); luteoforceps (Fan & Fang) (E. Palearctic, Larix); baicalensis (Elberg) (E. Palearctic, Larix); laricicola (Karl) (Palearctic, Larix); laricis sp.n. (Nearctic, Larix); macalpinei sp.n. (W. Canada, Larix); carbonaria (Ringdahl) (C. Europe, E. Nearctic, Abies); svenssoni sp.n. (N. Europe, Mongolia); suwai sp.n. (Japan); todocola (Suwa) (Japan, Abies); abietis (Huckett) (Nearctic, Abies); and oriens (Suwa) (E. Palearctic, Abies).  相似文献   

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The results of a revision of the Sciaridae (Diptera: Nematocera) from the British Isles are presented, carried out as a preliminary to the preparation of a new Handbook for the identification of the British and Irish fauna of this family. A total fauna of 263 species is confirmed, including many species new to the British Isles: 111 new to Great Britain and 32 new to Ireland. Epidapus ( Pseudoaptanogyna ) echinatum Mohrig & Kozánek, 1992 , hitherto known only from North Korea, is newly recorded from Europe. Six species are described as new to science: Bradysia austera Menzel & Heller sp. nov. , Bradysia ismayi Menzel sp. nov. , Bradysia nigrispina Menzel sp. nov. , Corynoptera flavosignata Menzel & Heller sp. nov. , Corynoptera uncata Menzel & Smith sp. nov. and Epidapus subgracilis Menzel & Mohrig sp. nov . The following new synonymies are proposed: Leptosciarella nigrosetosa (Freeman, 1990) =  Leptosciarella truncatula Mohrig & Menzel, 1997 ; Sciara nursei Freeman, 1983 =  Sciara ulrichi Menzel & Mohrig, 1998. Many misidentifications in the previous literature are corrected. Details of the collection data and location of specimens examined are provided under each species. The localities from which Sciaridae were collected in the British Isles are documented by modern county and grid references and the habitat indicated where known, to assist in assessing the ecological requirements of each species.  © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society , 2006, 146 , 1–147.  相似文献   

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