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1.
Macrobrachium (Bate, 1868) is a large and cosmopolitan crustacean genus of high economic importance worldwide. We investigated the morphological and molecular identification of freshwater prawns of the genus Macrobrachium in South, South West, and Littoral regions of Cameroon. A total of 1,566 specimens were examined morphologically using a key described by Konan (Diversité morphologique et génétique des crevettes des genres Atya Leach, 1816 et Macrobrachium Bate, 1868 de Côte d'Ivoire, 2009, Université d'Abobo Adjamé, Côte d'Ivoire), leading to the identification of seven species of Macrobrachium: M. vollenhovenii (Herklots, 1857); M. macrobrachion (Herklots, 1851); M. sollaudii (De Man, 1912); M. dux (Lenz, 1910); M. chevalieri (Roux, 1935); M. felicinum (Holthuis, 1949); and an undescribed Macrobrachium species M. sp. To validate the genetic basis of the identified species, 94 individuals representing the species were selected and subjected to genetic characterization using 1,814 DArT markers. The admixture analysis revealed four groups: M. vollenhovenii and M. macrobrachion; M. chevalieri; M. felicinum and M. sp; and M. dux and M. sollaudii. But, the principal component analysis (PCA) separated M. sp and M. felicinum to create additional group (i.e., five groups). Based on these findings, M. vollenhovenii and M. macrobrachion may be conspecific, as well as M. dux and M. sollaudii, while M. felicinum and M. sp seems to be different species, suggesting a potential conflict between the morphological identification key and the genetic basis underlying speciation and species allocation for Macrobrachium. These results are valuable in informing breeding design and genetic resource conservation programs for Macrobrachium in Africa.  相似文献   

2.
The skeleton of the jaws and neurocranium of sturgeons (Acipenseridae) are connected only through the hyoid arch. This arrangement allows considerable protrusion and retraction of the jaws and is highly specialized among ray‐finned fishes (Actinopterygii). To better understand the unique morphology and the evolution of the jaw apparatus in Acipenseridae, we investigated the development of the muscles of the mandibular and hyoid arches of the Siberian sturgeon, Acipenser baerii. We used a combination of antibody staining and formalin‐induced fluorescence of tissues imaged with confocal microscopy and subsequent three‐dimensional reconstruction. These data were analyzed to address the identity of previously controversial and newly discovered muscle portions. Our results indicate that the anlagen of the muscles in A. baerii develop similarly to those of other actinopterygians, although they differ by not differentiating into distinct muscles. This is exemplified by the subpartitioning of the m. adductor mandibulae as well as the massive m. protractor hyomandibulae, for which we found a previously undescribed portion in each. The importance of paedomorphosis for the evolution of Acipenseriformes has been discussed before and our results indicate that the muscles of the mandibular and the hyoid may be another example for heterochronic evolution.  相似文献   

3.
Dispersal shapes demographic processes and therefore is fundamental to understanding biological, ecological, and evolutionary processes acting within populations. However, assessing population connectivity in scoters (Melanitta sp.) is challenging as these species have large spatial distributions that span remote landscapes, have varying nesting distributions (disjunct vs. continuous), exhibit unknown levels of dispersal, and vary in the timing of the formation of pair bonds (winter vs. fall/spring migration) that may influence the distribution of genetic diversity. Here, we used double‐digest restriction‐associated DNA sequence (ddRAD) and microsatellite genotype data to assess population structure within the three North American species of scoter (black scoter, M. americana; white‐winged scoter, M. deglandi; surf scoter, M. perspicillata), and between their European congeners (common scoter, M. nigra; velvet scoter, M. fusca). We uncovered no or weak genomic structure (ddRAD ΦST < 0.019; microsatellite FST < 0.004) within North America but high levels of structure among European congeners (ddRAD ΦST > 0.155, microsatellite FST > 0.086). The pattern of limited genomic structure within North America is shared with other sea duck species and is often attributed to male‐biased dispersal. Further, migratory tendencies (east vs. west) of female surf and white‐winged scoters in central Canada are known to vary across years, providing additional opportunities for intracontinental dispersal and a mechanism for the maintenance of genomic connectivity across North America. In contrast, the black scoter had relatively elevated levels of divergence between Alaska and Atlantic sites and a second genetic cluster found in Alaska at ddRAD loci was concordant with its disjunct breeding distribution suggestive of a dispersal barrier (behavioral or physical). Although scoter populations appear to be connected through a dispersal network, a small percentage (<4%) of ddRAD loci had elevated divergence which may be useful in linking areas (nesting, molting, staging, and wintering) throughout the annual cycle.  相似文献   

4.
Whirligig beetles, which are known for their rapid gliding on the water surface, have evolved a unique locomotor apparatus. External and internal thoracic structures of Orectochilus villosus (Orectochilini) are described in detail and documented with microcomputed tomography, computer‐based 3D reconstructions, and scanning electronic microscopy (SEM). The results are compared with conditions found in other genera of Gyrinidae and other groups of Coleoptera. The focus is on structures linked with locomotion, especially on the unusual flight apparatus, which differs strongly from that of other beetles. As in the other Orectochilini, the prothorax of Orectochilus displays characters typical for Gyrinidae, with triangular procoxae and forelegs transformed into elongated, sexually dimorphic grasping devices. The musculature of this segment is similar to the pattern found in other Coleoptera. Similar to all other extant Gyrinidae, the mesothorax is characterized by an extensive and flat mesoventrite, suitable for gliding on the water surface. As in Heterogyrinae and the other Gyrininae, the pterothoracic legs are transformed into paddle‐like structures, enabling the beetles to move with high speed on the surface film. The musculature of the mesothorax is reduced compared to other Coleoptera, but similar to what is found in the other Gyrininae. The metathoracic skeleton and musculature are simplified in Orectochilini compared to other Gyrininae and other groups of Coleoptera. In O. villosus, only 10 metathoracic muscles are preserved. 36 are present in an archostematan beetle, a condition probably close to the coleopteran ground plan. The metathoracic dorsal longitudinal bundles are absent in Gyrininae, muscles that play a role as indirect flight muscles in most other neopteran insects. The rest of the posteromotoric flight apparatus is distinctly modified, with a limited number of skeletomuscular elements taking over more functions. The large muscle M84 (IIIdvm7) M. noto–trochanteralis, for instance, functions as dominant wing levator, but is also responsible for the powerful and rapid backstroke of the hind legs. The presence of this muscle is a synapomorphy of Heterogyrinae and Gyrininae. The narrow metafurca in the latter group is likely linked to its large size. The elytra likely contribute to the control of the flight of the beetle, whereas they shield and inhibit the flight apparatus during swimming.  相似文献   

5.
The snail Melanoides tuberculata has been used successfully in the control of some snails, intermediate host of parasitosis. Melanoides tuberculata has been found in Tunisia, but its effects on populations of native snail have not yet been evaluated in the field. Our objective is to determine whether M. tuberculata competed with Galba truncatula, using a field study. Twelve monthly investigations were carried out along an irrigation system in Ain Soltane's oasis (southwest of Tunisia). Here, we describe the population dynamics of G. truncatula with and without M. tuberculata in two stations: a witness pilot station (S1), in which the snail lives alone, and an experimental station (S2), where two species live together. The abundance of G. truncatula varied according to subsistence or not of M. tuberculata. The number of annual generations is higher in S1 (four generations) than S2 (two generations). In the absence of other molluscs or predators that can influence the density of G. truncatula and assuming that climatic factors are mitigated by the presence of an oasean microclimate, these results show that the mollusc M. tuberculata has a competition with the vector species of fluke.  相似文献   

6.
Mythimna separata (Walker) is a serious cosmopolitan pest. Trichogramma species have been used worldwide as biological control agents of lepidopteran pests. However, no data on the control efficiency of Trichogramma species on this pest have been reported. We evaluated the suitability of M. separata eggs for three Trichogramma species, Trichogramma dendrolimi Matsumura, T. ostriniae Pang et Chen and T. japonicum Ashmead, and compared the suitability with that of Corcyra cephalonica (Stainton) eggs. The parasitism rate, development time, emergence rate, female proportion, body size and egg load of female offspring indicated that the M. separata egg is a suitable host for the three Trichogramma species. On the other hand, the non‐emergence rate and the relationship between egg load and body size reflected that M. separata eggs are less suitable for the three Trichogramma species than C. cephalonica eggs. Egg resorption occurred in T. japonicum 4 days after emergence.  相似文献   

7.
Cases of geographically restricted co‐occurring sister taxa are rare and may point to potential divergence with gene flow. The two bat species Murina gracilis and Murina recondita are both endemic to Taiwan and are putative sister species. To test for nonallopatric divergence and gene flow in these taxa, we generated sequences using Sanger and next‐generation sequencing, and combined these with microsatellite data for coalescent‐based analyses. MtDNA phylogenies supported the reciprocally monophyletic sister relationship between M. gracilis and M. recondita; however, clustering of microsatellite genotypes revealed several cases of species admixture suggesting possible introgression. Sequencing of microsatellite flanking regions revealed that admixture signatures stemmed from microsatellite allele homoplasy rather than recent introgressive hybridization, and also uncovered an unexpected sister relationship between M. recondita and the continental species Murina eleryi, to the exclusion of M. gracilis. To dissect the basis of these conflicts between ncDNA and mtDNA, we analysed sequences from 10 anonymous ncDNA loci with *beast and isolation‐with‐migration and found two distinct clades of M. eleryi, one of which was sister to M. recondita. We conclude that Taiwan was colonized by the ancestor of M. gracilis first, followed by the ancestor of M. recondita after a period of allopatric divergence. After colonization, the mitochondrial genome of M. recondita was replaced by that of the resident M. gracilis. This study illustrates how apparent signatures of sympatric divergence can arise from complex histories of allopatric divergence, colonization and hybridization, thus highlighting the need for rigorous analyses to distinguish between such scenarios.  相似文献   

8.
In recent studies, the yeast species Hanseniaspora uvarum and Lachancea thermotolerans were isolated from the digestive tract of four North American yellowjacket species (Hymenoptera: Vespidae), and attraction of yellowjackets to brewer's yeast, Saccharomyces cerevisiae (all Saccharomycetaceae), growing on fruit powder was demonstrated. We tested the hypothesis that Vespula spp. are attracted to cultures of H. uvarum and L. thermotolerans and their respective volatiles. In field experiments, we found that H. uvarum and L. thermotolerans are attractive to three species of yellowjacket, but only when grown on grape juice‐infused yeast peptone dextrose (YPD) agar. Using gas chromatography‐mass spectrometry, we analyzed the headspace volatiles produced by these yeasts, and field tested an 18‐component yeast synthetic semiochemical blend. This synthetic blend attracted western yellowjackets, Vespula pensylvanica (Saussure), but no other yellowjacket species. Acetic acid or ethanol added to the synthetic blend at biologically relevant doses either had no effect or significantly lowered trap captures. Our results demonstrate that yeast symbionts isolated from the digestive tract of yellowjackets are attractive to their hosts. Further research is needed to identify the volatiles mediating attraction of species other than V. pensylvanica to the yeast cultures.  相似文献   

9.
Stone marten (Martes foina) and European pine marten (M. martes) occur in western Eurasia. Current distributions of martens within Turkey and phylogenetic relationships among the Turkish and other populations of the two species within Eurasia remain relatively unknown. In this study, we aimed to determine genetic diversity within Martes populations inhabiting Turkey and to reveal the phylogenetic relationships among the Turkish and conspecific populations of the two marten species, using mitochondrial cytochrome b (CytB) sequences. Twenty‐four (24) haplotypes were identified among 86 marten samples collected across Turkey, including 23 novel haplotypes. Genetic distances among the Turkish haplotypes ranged from 0.1% to 0.8%, with an average of 0.3%. The 24 Turkish haplotypes were analysed together with those of conspecific populations deposited in GenBank. Phylogenetic (Bayesian Inference, maximum likelihood, neighbor‐joining) and network analyses revealed that all of the Turkish samples belonged to M. foina and that samples of M. martes were not encountered. Haplotypes of M. foina were divided into five haplogroups. The haplogroup including the two Chinese samples differed markedly from other the haplogroups. The remaining haplogroups contained samples from both the Turkish and European populations. We found that there was a genetically close relationship between the Turkish and the European stone marten populations. As a result of this study, M. martes may not be distributed in the Anatolian part of Turkey, possibly due to a barrier effect of two straits (Dardanelles and Bosporus) and the Caucasus Mountains. On the other hand, M. foina is distributed in both the Anatolian and Thracian parts of Turkey. Our results suggest that Turkey was likely one of the refuges for M. foina during Pleistocene glacial periods and is one of the centres of distribution of stone marten for Europe and the surrounding regions.  相似文献   

10.
Cranial variation was studied across the geographical range of the Meriones meridianus species complex using 665 specimens from 112 localities. Morphometric results were compared with previously published data on genetic variation. Unsupervised model‐based clustering analysis implemented in Mclust software was employed to identify the number and content of morphological clusters. Three clearly defined morphological groups corresponding to mtDNA clades were found. The results of the morphometric analysis are consistent with the hypothesis that these 3 groups should be treated as distinct species; specifically, M. psammophilus Milne‐Edwards, 1871, M. penicilliger Heptner, 1933 and M. meridianus Pallas, 1773. M. psammophilus inhabits the Mongolian–Chinese part of the superspecies range, except for the Mongolian Dzungaria region, which is inhabited by M. meridianus. The range of the latter species extends westwards to north‐west Kazakhstan and Kalmykia. M. penicilliger inhabits the southern part of the superspecies range from Tian Shan to Turkmenistan. M. dahli is craniometrically similar to M. meridianus; hence, its species status remains questionable.  相似文献   

11.
12.
Species in the genus Gracilaria that display conspicuously flattened vegetative morphologies are a taxonomically challenging group of marine benthic red algae. This is a result of their species richness, morphological similarity, and broad phenotypic plasticity. Within this group, the Gracilaria domingensis complex is one of the most common, conspicuous, and morphologically variable species along the tropical western Atlantic Ocean. Previous research has identified that members of this complex belong to two distantly related clades. However, despite this increased phylogentic resolution, species delimitations within each of these clades remain unclear. Our study assessed the species diversity within this difficult complex using morphological and molecular data from three genetic markers (cox1, UPA, and rbcL). We additionally applied six single‐marker species delimitation methods (SDM: ABGD, GMYCs, GMYCm, SPN, bPTP, and PTP) to rbcL, which were largely in agreement regarding species delimitation. These results, combined with our analysis of morphology, indicate that the G. domingensis complex includes seven distinct species, each of which are not all most closely related: G. cervicornis; a ressurected G. ferox; G. apiculata subsp. apiculata; a new species, Gracilaria baiana sp. nov.; G. intermedia subsp. intermedia; G. venezuelensis; and G. domingensis sensu stricto, which includes the later heterotypic synonym, G. yoneshigueana. Our study demonstrates the value of multipronged strategies, including the use of both molecular and morphological approaches, to decipher cryptic species of red algae.  相似文献   

13.
The effects of sedimentation and substrate orientation on algal and sessile invertebrate assemblages were tested on an annual population of Macrocystis pyrifera in Metri Bay, southern Chile. In the laboratory, M. pyrifera zoospores were seeded on Crepipatella fecunda shells, the primary substrate for M. pyrifera in this system. The seeded shells were deployed at Metri Bay inside cages and were orientated vertically and horizontally under two sedimentation regimes (bottom and suspended). Due to differences in grazer accessibility and the species present between the sedimentation treatments, grazers (>1 cm) were excluded. We followed sporophyte development of M. pyrifera and the natural recruitment of other algal and invertebrate species. Sedimentation rates were significantly higher in the cages attached to the bottom compared to suspended cages (P < 0.001). In total M. pyrifera and three additional algal genera were detected and all algal recruits showed significantly greater recruitment on the horizontally orientated substrate compared to the vertical substrate. Macrocystis pyrifera sporophytes were present only on the horizontal, suspended (less sedimentation) treatment. In contrast, Ulva and Ectocarpus spp. also occurred in the horizontal, high sediment treatment. Invertebrate recruitment (amphipods, barnacles and spirorbids) dominated the vertically oriented shells regardless of sedimentation. Results indicate that high sedimentation negatively affected the development of M. pyrifera sporophytes while other opportunistic species were able to recruit under these conditions.  相似文献   

14.
The morphology and infraciliature of a new ciliate, Metopus yantaiensis n. sp., discovered in coastal soil of northern China, were investigated. It is distinguished from its congeners by a combination of the following features: nuclear apparatus situated in the preoral dome; 18–21 somatic ciliary rows, of which three extend onto the preoral dome (dome kineties); three to five distinctly elongated caudal cilia, and 21–29 adoral polykinetids. The 18S rRNA genes of this new species and two congeners, Metopus contortus and Metopus hasei, were sequenced and phylogenetically analyzed. The new species is more closely related to M. hasei and the clevelandellids than to other congeners; both the genus Metopus and the order Metopida are not monophyletic. In addition, the digestion‐resistant bacteria in the cytoplasm of M. yantaiensis were identified, using a 16S rRNA gene clone library, sequencing, and fluorescence in situ hybridization. The detected intracellular bacteria are affiliated with Sphingomonadales, Rhizobiales, Rickettsiales (Alphaproteobacteria), Pseudomonas (Gammaproteobacteria), Rhodocyclales (Betaproteobacteria), Clostridiales (Firmicutes), and Flavobacteriales (Bacteroidetes).  相似文献   

15.
Mitochondria are archetypal eukaryotic organelles that were acquired by endosymbiosis of an ancient species of alpha‐proteobacteria by the last eukaryotic common ancestor. The genetic information contained within the mitochondrial genome has been an important source of information for resolving relationships among eukaryotic taxa. In this study, we utilized mitochondrial and chloroplast genomes to explore relationships among prasinophytes. Prasinophytes are represented by diverse early‐diverging green algae whose physical structures and genomes have the potential to elucidate the traits of the last common ancestor of the Viridiplantae (or Chloroplastida). We constructed de novo mitochondrial genomes for two prasinophyte algal species, Pyramimonas parkeae and Cymbomonas tetramitiformis, representing the prasinophyte clade. Comparisons of genome structure and gene order between these species and to those of other prasinophytes revealed that the mitochondrial genomes of P. parkeae and C. tetramitiformis are more similar to each other than to other prasinophytes, consistent with other molecular inferences of the close relationship between these two species. Phylogenetic analyses using the inferred amino acid sequences of mitochondrial and chloroplast protein‐coding genes resolved a clade consisting of P. parkeae and C. tetramitiformis; and this group (representing the prasinophyte clade I) branched with the clade II, consistent with previous studies based on the use of nuclear gene markers.  相似文献   

16.
17.
We analyzed variations in chloroplast DNA (cpDNA) in the widespread herbaceous species Hosta sieboldiana and Hosta albomarginata across large portions of their geographic ranges in the Japanese archipelago. Our objective was to compare the phylogeographic histories and phylogeographic structures of the two congeneric species in the Japanese archipelago. The location of the study is Japanese archipelago. We sequenced 1380 bp of noncoding cpDNA from 45 populations of H. sieboldiana (= 362) and 55 populations of H. albomarginata (= 436) to assess genetic variations within and among populations across almost the entire distributions of the species in Japan. Extant patterns of geographic structure were analyzed using statistical parsimony networks and spatial analysis of molecular variance (SAMOVA). We also used Monmonier's algorithm to detect genetic barriers between regions. Relationships between the populations were examined using a neighbor‐joining (NJ) method. Four haplotypes were found for H. sieboldiana, whereas eight haplotypes were identified for H. albomarginata. Total genetic haplotype diversity (hT) and within‐population haplotype diversity (hS) for H. sieboldiana were 0.352 and 0.040, respectively, while the values for Halbomarginata were 0.529 and 0.085, respectively. The population differentiations (GST) for H. sieboldiana and Halbomarginata were 0.839 and 0.886, respectively. The SAMOVA analysis revealed two clusters in H. sieboldiana and four clusters in H. albomarginata. Differentiations between and among the clusters were supported by the BARRIER analysis and the NJ tree. We detected differences in the population genetic structure between the two species. We found that H. sieboldiana had lower haplotype diversity than H. albomarginata. These results may be partially explained by the difference in ecological habitats and geographic distributions between the species. Hosta albomarginata is more widely distributed than Hsieboldiana in East Asia including Russia, and this large distribution range would enable more chances to intraspecific gene flow.  相似文献   

18.
Crop plant domestication can change plant resistance to herbivores leading to differences in pest pressure experienced by crop plants and their wild relatives. To compare resistance to herbivores between domesticated and wild fruit trees, we quantified direct resistance and indirect resistance to a pest insect, the florivorous apple blossom weevil Anthonomus pomorum (Coleoptera: Curculionidae), for the cultivated apple Malus domestica and two wild apple species, the European crab apple M. sylvestris and the exotic M. kirghisorum. We measured weevil infestation and performance (weight, sex ratio), and weevil parasitism by parasitoid wasps for different cultivars of M. domestica and for the two wild apple species. To explain weevil and parasitoid responses to different apple species, we quantified tree characteristics including nitrogen content, size of flower buds, bark roughness, tree size, tree phenology and tree position. We found significant differences in susceptibility to weevil infestation between apple species, with lowest infestation (highest apple resistance) in M. domestica and highest infestation in M. kirghisorum. The suitability of apple species also varied significantly: weevils emerging from M. sylvestris were significantly lighter than those from M. kirghisorum. Parasitism of A. pomorum by different parasitoid species was significantly higher in M. sylvestris than in M. domestica. Infestation, weevil weight and parasitism were positively related to tree characteristics: infestation to bud nitrogen content and bark roughness, weevil size to nitrogen content and bud size, and parasitism to tree height and bud density. Our study revealed marked differences between apple species in susceptibility and suitability for the pest herbivore, but also for antagonistic parasitoids. Whereas direct resistance appeared to be higher in cultivated apple, indirect resistance via parasitoids was apparently higher in wild apple trees. Our findings suggest that wild and cultivated apple trees possess different resistance traits that may be combined to optimize resistance in commercial apple cultivars.  相似文献   

19.
A multigene phylogeny using COI‐5P (mitochondrial cytochrome c oxidase subunit 1), psbA (PSII reaction center protein D1), and EF2 (elongation factor 2) sequence data for members of the tribe Corallineae was constructed to assess generic boundaries. We determined that traditional reliance on conceptacle position as an indicator of generic affinities in the Corallineae is not supported and taxonomic changes are required. We found that species currently assigned to Pseudolithophyllum muricatum resolved within the Corallineae in all analyses. This is the first record of crustose members in the subfamily Corallinoideae. Further‐more, the genus Serraticardia was polyphyletic; we propose to synonomize Serraticardia with Corallina, transfer the type species Smaxima to Corallina (Cmaxima (Yendo) comb. nov.), and describe the new genus Johansenia for Smacmillanii (Jmacmillanii (Yendo) comb. nov.). Our molecular data also indicate that species in the genus Marginisporum have evolutionary affinities among species of Corallina and these genera should also be synonymized. This necessitates the combinations Caberrans (Yendo) comb. nov. for Maberrans (Yendo) Johansen & Chihara, Ccrassissima (Yendo) comb. nov. for M. crassissimum (Yendo) Ganesan, and C. declinata (Yendo) comb. nov. for M. declinata (Yendo) Ganesan. Corallina elongata was divergent from all other members of Corallina and is transferred to a new genus, Ellisolandia (E. elongata (J. Ellis & Solander) comb. nov). In addition, COI‐5P and internal transcribed spacer (ITS) data combined with morphological characters were used to establish that rather than the four Corallina species recognized in Canada, there are nine.  相似文献   

20.
Three ontogenetic stages of the African catfish Clarias gariepinus have been used to describe and discuss the ontogeny of the hyoid musculature. During ontogeny, an asynchrony in the development of the muscles is observed: the intermandibularis and protractor hyoidei are the first to develop and which bear their insertions, followed by the hyohyoideus inferior and the sternohyoideus. The hyohyoideus abductor and adductor muscles are the last of the hyoid muscles to develop. In the juvenile stage (136.2 mm SL specimen), the intermandibularis is still present. The protractor hyoidei is well developed, as it may play an important role in the opening of the mouth, the elevation of the hyoid bars and, as a typical catfish feature, the displacement of the mandibular barbels. The protractor hyoidei arises as three pairs of muscle bundles (a pars ventralis, a pars lateralis and a pars dorsalis), of which the pars ventralis and the pars lateralis become fused to each other. This fusion gives rise to four different fields of superficial fibres for the manipulation of the mandibular barbels. The pars dorsalis, with its tendinous insertion, may be of more importance for mouth opening and/ or hyoid elevation. The hyohyoid muscle is well differentiated into an inferior, abductor and adductor muscles, acting on the hyoid bars, the branchiostegal rays and the opercular bone.  相似文献   

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