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1.
In a sample of 108 underground voles from 23 Greek localities, the species Microtus felteni, M. guentheri, M. rossiaemeridionalis and M. subterraneus were identified, based on external body morphology and karyotype. Moreover, the implemented C-banding staining technique revealed the heterochromatin distribution in the chromosomes of the above species. All M. guentheri (2n=54, FN=54) and M. rossiaemeridionalis (2n=54, FN=56) specimens displayed the typical karyotypes of these species, respectively. The M. subterraneus specimens belonged to the chromosomal race with 2n=52, FN=60 of this species, apart from a single individual that demonstrated a medium-sized, subtelocentric autosome in heterozygous condition (2n=52, FN=61). Furthermore, M. felteni individuals, trapped again after many years, were karyologically studied (2n=54, FN=56) and the C-banding pattern for this species is hereby presented for the first time. Finally, the study of meiotic preparations in M. guentheri and M. rossiaemeridionalis males verified the asynaptic behaviour of their sex chromosomes. The karyotype of the four studied Microtus species does not seem to have diversified much from the putative ancestral arvicoline karyotype (2n=56, FN=56). On the other hand, the heterochromatin accumulation in the sex chromosomes, particularly prominent in M. felteni and M. rossiaemeridionalis, represents this common tendency in several Microtus species.  相似文献   

2.
In order to determine the phenotypic associations of four morphologically similar species of Microtus occurring in Turkey, we applied landmark-based shape analysis. The skulls of Microtus anatolicus, M. dogramacii, M. guentheri and M. levis (= M. rossiaemeridionalis) were found to differ significantly in terms of both size and shape. M. guentheri had the biggest skull, while M. levis had the smallest. Sexual dimorphism was found in the shape of the skull in M. dogramacii and M. levis. The tympanic bulla area is enlarged in M. anatolicus compared to the other species. Mahalanobis distances (the distance between a point and the group mean, taking into account the within-group covariance-variance matrix) confirm the distinction of the arvalis group (M. levis) and socialis group (Microtus anatolicus, M. dogramacii, M. guentheri).  相似文献   

3.
A general morphometrical analysis of the M1 was conducted to identify the subterranean vole species found in Upper Pleistocene localities from Serbia and Montenegro, and to clarify the systematic position and the phylogenetic relationships between the different species in the Balkans. From the different localities studied, we can assign one population toMicrotus (Terricola) thomasi and the others to theM. (T.) subterraneus group. This study suggests thatM. (T.) grafi can be considered as a chronological sub-species ofM. (T.) subterraneus or as a different but phylogenetically very close species.  相似文献   

4.
The endemic Balkan vole taxonMicrotus (Terricola) thomasi (Barrett-Hamilton, 1903) exhibits great karyological variability in Greece. In this study, populations belonging to two different karyotypic forms (‘atticus’ and ‘thomasi’) are examined both morphometrically and electrophoretically. A total of 140 individuals ofM. (T.) thomasi were collected from 6 localities of south and central Greece. For the morphometric analysis, 27 variables (external body and cranial characters) were examined and evaluated according to multivariate analyses (PCA, MANOVA, CVA and CLUS). For the electrophoretic analysis, 18 putative genetic loci were examined and the allozymic data were treated by the biostatistical package BIOSYS-1. According to the results obtained, all the populations studied show little overall morphometric variability, whereas they are characterized by high electrophoretic variability. The populations studied are not grouped according to the karyotypic form. In almost all the cases, in the two UPGMA-dendrograms plotted according to morphometric and electrophoretic distances (Mahalanobis’ and Nei’s distances, respectively), the populations branching together belong to different karyotypic forms. Conclusively, the morphometric and electrophoretic results of this study revealed that the two karyotypic forms should not be considered separate species or subspecies, as it has been proposed by some authors in the past, and the populations studied can be considered only as different local populations of the rather variable vole speciesM. (T.) thomasi.  相似文献   

5.
The present article extends our previous work on the phylogenetic history of Microtus (Terricola) thomasi, analysing cytochrome b, 12S rRNA, 16S rRNA and the control region in 65 Greek populations. The analysis revealed three clades: one grouping the populations from Peloponnisos (Southern Greece); the second, the populations from Agios (Ag.) Stefanos and Evvoia island (Central East Greece); and the third, all the remaining populations with no geographical substructure. Genetic distances were low for most populations, with only the populations of Evvoia and Ag. Stefanos being substantially distant. Thus, although this species has a recent colonization history and probably descends from a highly polymorphic ancestor, a monophyletic and highly differentiated lineage is formed in Greece and is distributed in Ag. Stefanos and Evvoia. Molecular differentiation, distinct geographical distribution and restriction of gene flow between this lineage and the rest of the Greek populations provide evidence for its probable subspecific status, Microtus (Tericola) thomasi atticus. A possible mechanism leading the differentiation process of the proposed subspecies is suggested, based on the displacement of this species in central Greece by its congeneric, probably better‐fitted Microtus (Microtus) guentheri and the subsequent separation of Ag. Stefanos and Evvoia from the remaining Greek populations. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 117–130.  相似文献   

6.
Diet composition of a generalist predator, the red fox (Vulpes vulpes) in relation to season (winter or summer) and abundance of multi-annually cyclic voles was studied in western Finland from 1983 to 1995. The proportion of scats (PS; a total of 58 scats) including each food category was calculated for each prey group. Microtus voles (the field vole M. agrestis and the sibling vole M. rossiaemeridionalis) were the main prey group of foxes (PS = 0.55) and they frequently occurred in the scats both in the winter and summer (PSs 0.50 and 0.62, respectively). There was a positive correlation between the PSs of Microtus voles in the winter diet of foxes and the density indices of these voles in the previous autumn. Other microtine rodents (the bank vole Clethrionomys glareolus, the water vole Arvicola terrestris and the muskrat Ondatra zibethicus) were consumed more in winter than in summer. The unusually high small mustelid predation by red foxes (PS = approx. 0.10) in our study area gives qualitative support for the hypothesis on the limiting impact of mammalian predators on least weasel and stoat populations. None of the important prey groups was preyed upon more at low than at high densities of main prey (Microtus voles). This is consistent with the notion that red foxes are generalist predators that tend to opportunistically subsist on many prey groups. Among these prey groups, particularly hares and birds (including grouse), were frequently used as food by foxes.  相似文献   

7.
Two long repeats, MS3 and MS4, are predominantly located in sex-chromosomal heterochromatin in common vole species [1]. Their tandem arrangement was revealed by means of the PCR analysis of genomic DNAs of four Microtus species and by restriction mapping of clones selected from a M. rossiaemeridionalis genomic library. Several mobile elements proved to be incorporated in a monomeric unit of each repeat and amplified together with its other components. In addition, LINE inserts were found in MS4 tandem arrays. The copy number of both repeats per haploid genome was estimated at 100–300 for euchromatin and 20,000–40,000 for the M. rossiaemeridionalis genome. The repeats were assumed to be the major component of sex-chromosomal heterochromatin DNA.  相似文献   

8.
We sequenced the entire cytochrome b gene in Microtus paradoxus from Turkmenistan and Microtus socialis from Crimea and Kalmykia. Phylogenetic relationships among social voles were reconstructed by the inclusion into analyses of a further 23 published haplotypes belonging to six species. The two probabilistic methods which were used in phylogenetic analyses, the Bayesian inference and Maximum Likelihood, yielded very similar results. Both trees showed two highly divergent lineages which were further subdivided into seven species. The socialis lineage encompassed four species (M. socialis, M. irani, M. anatolicus, and M. paradoxus), and the remaining three species clustered into the guentheri lineage (M. guentheri, M. hartingi, M. dogramacii). The ranges for nucleotide divergences between seven species of social voles (4.95–9.28% and 4.18–8.81% for mean and net divergences, respectively) mainly exceeded 4.3%, which is frequently regarded as the conservative cut-off between sibling species in the specious genus Microtus.  相似文献   

9.
We documented major changes in the zooplankton community of Flathead Lake following the appearance of Mysis relicta. The three common cladocerans found in the lake decreased in abundance, most notably Daphnia longiremis which disappeared from the lake. Copepods were also affected by M.relicta, especially Diacyclops thomasi which decreased in abundance by an order of magnitude. The only macrozooplankton species which seemed to benefit from the presence of M.relicta was Leptodiaptomus ashlandi. The varied responses of dominant zooplankton species appeared to be the result of a combination of factors. Laboratory feeding studies indicate that M.relicta preferred Cladocera over Copepoda, with the following order of feeding preference: Bosmina longirostris > D.longiremis >, Daphnia thorata > L.ashlandi > D.thomasi. The two zooplankton species which declined most following the appearance of M.relicta showed the greatest degree of habitat overlap with M.relicta. Daphnia longiremis and D.thomasi, together with M.relicta, are cold stenotherms and were concentrated in the hypolimnion during the summer. Finally, another trait shared by D.longiremis and D.thomasi was the absence of a diapause stage, which made them vulnerable to predation by M.relicta throughout the year.   相似文献   

10.
The evolutionary history of the genus Megadontomys, a group of mice allopatrically distributed along the cool‐humid forest in the highlands of México, is controversial. In this study, we examined phylogenetic relationships within the genus using sequences data from the complete mitochondrial cytochrome b gene. This information also allowed us to corroborate species limits, geographic boundaries of taxonomic entities and assess genetic variation within each taxon. The results of the phylogenetic analyses based on maximum likelihood, Bayesian inference and maximum parsimony were largely congruent in that M. nelsoni and M. thomasi were more closely related relative to M. cryophilus. These results are concordant with previous studies based on morphology and allozyme variation. However, testing of the alternative hypothesis of a closer evolutionary affinity between M. nelsoni–M. cryophilus did not produce a significantly less likely tree. The lack of unambiguous support towards one of these previously proposed contending hypotheses is congruent with the alternative scenario of an almost simultaneous diversification of the three species. Application of the phylogenetic species concept and the genetic species concept supports the recognition of three distinct taxonomic entities at the specific level. M. nelsoni inhabits the Sierra Madre Oriental (Hidalgo, Veracruz, and Puebla) including the Sierra Mazateca (Oaxaca); M. cryophilus is restricted to the Sierra de Juárez (Oaxaca); and M. thomasi occurs in portions of the Sierra Madre del Sur (Guerrero) and the Sierra Mixteca (Oaxaca). Our data show that M. thomasi is formed by two genetically distinct lineages that potentially may represent distinct Evolutionary Significant Units.  相似文献   

11.
The data on dental variability in natural populations of sibling species of common voles (“arvalis” group, genus Microtus) from European and Asian parts of the species’ ranges are summarized using a morphotype-based approach to analysis of dentition. Frequency distributions of the first lower (m1) and the third upper (M3) molar morphotypes are analyzed in about 65 samples of M. rossiaemeridionalis and M. arvalis represented by arvalis and obscurus karyotypic forms. Because of extreme similarity of morphotype dental patterns in the taxa studied, it is impossible to use molar morphotype frequencies for species identification. However, a morphotype-based approach to analysis of dental variability does allow analysis of inter-species comparisons from an evolutionary standpoint. Three patterns of dental complexity are established in the taxa studied: simple, basic (the most typical within the ranges of both species), and complex. In M. rossiaemeridionalis and in M. arvalis obscurus only the basic pattern of dentition occurs. In M. arvalis arvalis, both simple and basic dental patterns are found. Analysis of association of morphotype dental patterns with geographical and environmental variables reveals an increase in the number of complex molars with longitude and latitude: in M. arvalis the pattern of molar complication is more strongly related to longitude, and in M. rossiaemeridionalis—to latitude. Significant decrease in incidence of simple molars with climate continentality and increasing aridity is found in M. arvalis. The simple pattern of dentition is found in M. arvalis arvalis in Spain, along the Atlantic coast of France and on islands thereabout, in northeastern Germany and Kirov region in European Russia. Hypotheses to explain the distribution of populations with different dental patterns within the range of M. arvalis sensu stricto are discussed.  相似文献   

12.
Brunet-Lecomte, P. & Chaline, J. 1991 01 15: Morphological evolution and phylogcnctic relationships of the European ground voles (Arvicolidae. Rodentia). Lethaia. Vol. 24. pp. 45–53. Oslo. ISSN 0024–1164. A new morphological study of the first lower molar M1 of European Quaternary ground voles (Arvicolidac. Rodcntia. Microtus (Terricola)) by means of multivariate analysis renews the systematics. phylogenetic relationships and their evolutionary group history. An Allophaiomyan origin of ground voles has been confirmed and the evolution of Mediterranean and middle Europcan groups has now been clarified. Primitive species of middle European groups display plesiomorphics. except for M. (T.) arvalidens, which shows certain apomorphies of the present species. The occurrence of M. (T.) multiplex in France at the end of the middle Pleistocene before the appearance of M. (T.) suhterraneus completely reverses previous ideas which considered that M. (T.) multiplex was a sibling species derived from M. (T.) subterraneus during the Würmian glaciation. The Atlantic species M. (T.) pyrenaicus is probably derived from the middle Pleistocene species M. (T.) mariaclaudiue whose exact origin is unknown. M. (T.) sauii, M. (T.) tarentina. M. (T.) melirensis and M. (T.) henseli belong to the same geographic group. Perhaps M. (T.) savii derived from M. (T.) tarentina or shares the same ancestor with M. (T.) tarentina. M. (T.) duodecimcostarus probably indirectly derived from an Iberian specics of Allophuiomys such as A. chalinei, while M. (T.) lusitanicus was separated from M. (T.) duodecimcostutus about 60,000 years ago. A sketch of the stratigraphical records and geographical distribution of the Terricola species in Western Europe showing their phylogenetic relationships and migrations during the middle and upper Pleistocene is included. Morphometry, variance analysis, phylogeneric relationships. Mammalia. Rodentia. Arvicolidae. Microtus, Terricola.  相似文献   

13.
The social vole of Cyrenaica, Libya, is the only extant representative of the Cricetidae family found in Africa. Its taxonomic status has been under debate, partly due to the problematic systematics of the entire group of social voles and partly due to the lack of morphological and molecular data from Cyrenaican specimens. In this study, we applied ancient DNA protocols to produce three cytochrome b (cytb) sequences of Cyrenaican voles and built a phylogenetic reconstruction (195 sequences in total) incorporating all available cytb sequences of the remaining social voles, other representatives of the genus Microtus and closely related cricetids. We used this phylogeny to test the performance of the model-based, single-locus, species delimitation approach implemented in mPTP and delimited nine species of social voles. Among them are the Cyrenaican vole, Microtus mustersi and its sister species M. guentheri, distributed along the Mediterranean coasts of southwestern Asia. Biogeographical reconstruction of ancestral area and molecular clock estimations of the time since the divergence of the two sister lineages suggest that their common ancestor dispersed into Africa through a coastal route and was isolated in Cyrenaica as a result of population fragmentation associated with Middle Pleistocenic pluvial/interpluvial cycles. Geographic isolation triggered the speciation process, but species distribution modeling gave evidence of subsequent niche divergence; M. guentheri has adapted to the xeric conditions of its distributional area, while M. mustersi benefited from the milder Cyrenaican climate. The Cyrenaican vole is a relict species more than 200,000 years old, has a small and isolated distribution and probably merits conservation.  相似文献   

14.
Delimitation of species is often complicated by discordance of morphological and genetic data. This may be caused by the existence of cryptic or polymorphic species. The latter case is particularly true for certain snail species showing an exceptionally high intraspecific genetic diversity. The present investigation deals with the Trochulus hispidus complex, which has a complicated taxonomy. Our analyses of the COI sequence revealed that individuals showing a T. hispidus phenotype are distributed in nine highly differentiated mitochondrial clades (showing p‐distances up to 19%). The results of a parallel morphometric investigation did not reveal any differentiation between these clades, although the overall variability is quite high. The phylogenetic analyses based on 12S, 16S and COI sequences show that the T. hispidus complex is paraphyletic with respect to several other morphologically well‐defined Trochulus species (T. clandestinus, T. villosus, T. villosulus and T. striolatus) which form well‐supported monophyletic groups. The nc marker sequence (5.8SITS228S) shows only a clear separation of T. o. oreinos and T. o. scheerpeltzi, and a weakly supported separation of T. clandestinus, whereas all other species and the clades of the T. hispidus complex appear within one homogeneous group. The paraphyly of the T. hispidus complex reflects its complicated history, which was probably driven by geographic isolation in different glacial refugia and budding speciation. At our present state of knowledge, it cannot be excluded that several cryptic species are embedded within the T. hispidus complex. However, the lack of morphological differentiation of the T. hispidus mitochondrial clades does not provide any hints in this direction. Thus, we currently do not recommend any taxonomic changes. The results of the current investigation exemplify the limitations of barcoding attempts in highly diverse species such as T. hispidus.  相似文献   

15.
《Systematic Entomology》2018,43(1):136-146
Phylogenetic analyses and species delimitation methods are powerful tools for understanding patterns of species diversity. Given the current biodiversity crisis, such approaches are invaluable for urgent assessment and delimitation of truthful species, particularly of endangered and morphologically cryptic taxa from vulnerable areas submitted to strong climate change and progressive human intervention such as the M editerranean region. In this study, we applied two DNA ‐based species delimitation methods and performed a B ayesian phylogenetic reconstruction using three mitochondrial gene fragments (12S , 16S and COI) to solve several taxonomic uncertainties among species of cross‐backed grasshoppers (genus Dociostaurus F ieber) from the western M editerranean. P hylogenetic analyses demonstrate the polyphyletic character of subgenera Dociostaurus , Kazakia B ey‐B ienko and Stauronotulus T arbinsky and, thus, the necessity of revising the currently accepted taxonomic subgenera within the genus Dociostaurus . We propose the split of closely related taxa with allopatric distributions such as D. (S.) kraussi and D. (S.) crassiusculus , considering the later a distinct species limited to the I berian P eninsula and excluding the name crassiusculus from other forms of D. (S.) kraussi from E ast E urope and A sia. Estimates of divergence times indicate that diversification of Dociostaurus probably happened during the M iocene–P liocene (3–7 Ma), and the split of the studied pairs of sister taxa took place during the middle and late P leistocene (1–2 Ma). This study highlights the need for more molecular studies on the genus and their different species for a better understanding of their evolution, genetic variation and population dynamics in order to prioritize strategies for their adequate conservation and management.  相似文献   

16.
The Persian Jird, Meriones persicus, is distributed from Eastern Anatolia to Afghanistan and western Pakistan. Six subspecies were described based on skull features and coat colours, but the validity of these subspecies is uncertain, and no molecular work has ever been conducted on this species. Iran appears to be a key geographical region in which to revise the systematic and evolutionary history of this species, because five of the six subspecies are present in this country. To evaluate the phylogeographical history and taxonomy of this species in Iran, we used a combination of genetic (cytochrome b gene sequences of 70 specimens) and geometric morphometric (2D landmarks on the ventral side of skull of 258 specimens) analyses. We also used ecological niche modelling to make inferences about the evolutionary history of these lineages. Our molecular data highlight the existence of four genetic lineages, but they only partly correspond to the previously described subspecies. Our molecular and morphometric data confirm the validity of M. p. rossicus and show that it has a wider geographical range than previously thought. M. p. gurganensis and M. p. baptistae are genetically very close. The skull of M. p. gurganensis is morphologically distinguishable from other subspecies. The subspecies M. p. persicus and M. p. baptistae are genetically distinct, but morphologically close. Meriones p. ambrosius is genetically close to M. p. persicus, and additional analyses with more specimens are needed to validate its subspecific status. The genetic structure observed in Iran seems to fit the topography and biogeography of the country and emphasize the role of the Abarkooh, Central and Lut deserts as barriers to gene flow. All intraspecific divergent events within the Persian Jird occurred during the last 1.4 My, suggesting that climatic changes probably trigger diversification within this species. Our genetic and species niche modelling results suggest that potential refugial areas persisted during glacial periods for this species in north‐western Zagros Mountains, north‐eastern Alborz Mountains and Kohrud Mountains.  相似文献   

17.
The genus Mustelus is the most species‐rich of the widespread family Triakidae whereby its taxonomy and systematics have been historically challenging. They represent a significant fraction of the shark catches of small‐scale fisheries in the Gulf of California. In order to provide information useful for their management and conservation, the morphological and genetic distinction of the four species found in the northern Gulf of California (M. albipinnis, M. californicus, M. henlei and M. lunulatus) were analyzed. Discriminant analysis of 10 morphometric variables placed each species in a distinct and significantly different region of multivariate morpho‐space. The variables contributing most to their distinction were inter‐nostril width, mouth length, upper and lower labial furrow length, and mouth width. Restriction fragment length polymorphisms (PCR‐RFLP) of the nuclear ITS2 ribosomal DNA (rDNA) confirmed that each species represents a genetically cohesive and independent evolutionary lineage. In spite of the difficulty in differentiating these Mustelus species, a few cephalic measurements are useful to separate them. A PCR‐RFLP assay (using RsaI and MspI on ITS2 rDNA amplicons) is also proposed for the molecular differentiation of these commercially harvested smooth‐hound sharks, constituting the first molecular marker available for their identification. These data provide morphological and genetic tools that can be used to improve their management and conservation.  相似文献   

18.
Six species of bothrobiontic flies of 3 families (Phoridae, Helomyzidae, and Sphaeroceridae) were recorded from nests of the European pine vole Microtus (Terricola) subterraneus Sel.-Long. in Belgorod Province (“Forest on the Vorskla River” Nature Reserve). Four species are recorded in the fauna of Russia for the first time. Original Russian Text ? V.A. Krivokhatsky, E.P. Nartshuk, 2007, published in Entomologicheskoe Obozrenie, 2007, Vol. 86, No. 1, pp. 100–103.  相似文献   

19.
20.
The systematics and taxonomy of the Neotropical genus Micronycteris are not yet resolved; previous studies evidenced paraphyletic relationships, a number of potential undescribed species, and inadequate diagnostic characters. This revision focuses on the pale-bellied members of the genus using phylogenetic and morphometric tools, an increased sample size with all recognized taxa, and an expanded geographic coverage relative to prior studies. For the genetic analyses (n = 166), four molecular markers were concatenated, one mitochondrial (cytb), one nuclear (Fgb-I7), and two Y-chromosomal (DBY5 and DBY7). In the Bayesian and maximum likelihood analyses, the recognized subgenera Schizonycteris, Leuconycteris, Xenoctenes, and Micronycteris were recovered as monophyletic. The pale-bellied subgenera, Schizonycteris and Leuconycteris, were not sister clades; thus, venter coloration was not monophyletic. Leuconycteris was sister to the dark-bellied Micronycteris, and Schizonycteris was sister to the rest of the genus. Micronycteris schmidtorum was genetically defined for the first time, and it was determined all previous phylogenetic studies used a misidentified M. minuta from Bolivia. Our results showed a sister relationship between M. schmidtorum and M. brosseti, which redefines Leuconycteris. The subgenus Schizonycteris was also redefined, and it presented two well-supported clades from Central America and western Ecuador that are described as new species. Results are supported by a multivariate morphometric analyses (n = 114), karyological, and morphological comparisons. The taxonomic implications are discussed and emended diagnoses presented for the pale-bellied subgenera and for M. schmidtorum.  相似文献   

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