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1.
Myrceugenia is a genus endemic to South America with a disjunct distribution: 12 species occurring mainly in central Chile and approximately 25 in southeastern Brazil. Relationships are reconstructed within Myrceugenia from four plastid markers (partial trnK-matK, rpl32-trnL, trnQ-5'rps16 and rpl16) and two ribosomal nuclear regions (ETS and ITS) using maximum parsimony and Bayesian analyses. Relationships inferred previously from morphological data are not completely consistent with those from molecular data. All molecular analyses support the hypothesis that Myrceugenia is monophyletic, except for M. fernadeziana that falls outside the genus. Chilean species and Brazilian species form two separate lineages. Chilean species form three early diverging clades, whereas Brazilian species are a strongly supported monophyletic group in a terminal position. Least average evolutionary divergence, low resolution, short branches, and high species diversity found in the Brazilian clade suggest rapid radiation. Geographical distributions and phylogenetic reconstructions suggest that extant Myrceugenia species arose in northern Chile followed by colonization southward and finally to the Juan Fernández Islands and southeastern Brazil.  相似文献   

2.
中国合叶苔属(Scapania)两个新记录种   总被引:1,自引:1,他引:0  
曹同  于晶  宋国元 《植物研究》2003,23(2):134-136,T001,T002
报道了于我国四川发现的苔类植物合叶苔属(Scapania)的中国2个新记录种:兜瓣合叶苔(Scapania cuspiduligera(Nees)K.Muell.)和长叶合叶苔(Scapania glaucocephala(Tayl)Aust.)。  相似文献   

3.
Diplasiolejeunea is a pantropical, epiphytic genus of leafy liverworts that occurs from the lowlands to more than 4000m altitude. Phylogenetic analyses of a molecular dataset consisting of three markers (nuclear ribosomal ITS region, plastidic trnL-F region and rbcL gene) and 122 accessions (plus two outgroups, Colura and Cololejeunea) indicate that the evolutionary diversity of Diplasiolejeunea is underestimated by current morphology-based classification. Four morphologically semi-cryptic species have been recovered. The molecular phylogenies support a deep split into a Neotropical and a Paleotropical clade, the latter structured into Australasian, Asian and Afromadacascan lineages. Presented results confirm the ranges of two pantropical species (D. cavifolia, D. rudolphiana), provide evidence for dispersal from the Neotropics into the Paleotropics, indicate speciation along altitudinal gradients and demonstrate extensive morphological homoplasy. We propose a revised supraspecific classification of Diplasiolejeunea into a predominantly Paleotropical subgenus Physolejeunea and predominantly Neotropical subgenera Austrolejeuneopsis and Diplasiolejeunea, the former containing mainly epiphytic species, the latter mainly epiphylls. Several clades are supported by combinations of morphological character states, and could be assigned to sections at some later point. This is the first comprehensive phylogeny of a largely epiphyllous genus of liverworts.  相似文献   

4.
The current classification of the Malagasy-Comoroan geckos of the genus Geckolepis recognizes three valid species and is based on morphological differences only. Species allocation of individuals is difficult, mainly because of the insufficiently known degree of variation and the frequent partial loss of the integument in preserved specimens. Here we study Geckolepis specimens from almost their entire known range. We combine molecular and morphological data to estimate species richness in the genus, and to assess the taxonomic validity of the morphological differences proposed. Analyses of mitochondrial (12S, ND4) and nuclear (RAG1, CMOS) gene sequences support three major clades in addition to the morphologically distinct G. polylepis (included for 12S only), and the presence of various divergent lineages within these clades, some occurring in sympatry. Among lineages, the external morphology seems to be comparatively conservative, and differences are faint in many cases. For each major lineage, we summarize the most diagnostic morphological characters that distinguish it from other lineages. The combined molecular and morphological data strongly indicate the presence of highly divergent lineages, three of which are tentatively referred to the names Geckolepis maculata, G. polylepis and G. typica, whereas three other major lineages are considered Confirmed Candidate Species. Among the remaining lineages, differentiation is shallower, and these may qualify for Deep Conspecific Lineages. In conclusion, our analysis provides evidence for an underestimation of species richness in the genus and a complex evolutionary history, not reflected by current Geckolepis species-level taxonomy.  相似文献   

5.
The Monotropoideae (Ericaceae) are nonphotosynthetic plants that obtain fixed carbon from their fungal mycorrhizal associates. To infer the evolutionary history of this symbiosis we identified both the plant and fungal lineages involved using a molecular phylogenetic approach to screen 331 plants, representing 10 of the 12 described species. For five species no prior molecular data were available; for three species we confirmed prior studies which used limited samples; for five species all previous reports are in conflict with our results, which are supported by sequence analysis of multiple samples and are consistent with the phylogenetic patterns of host plants. The phylogenetic patterns observed indicate that: (i) each of the 13 plant phylogenetic lineages identified is specialized to a different genus or species group within five families of ectomycorrhizal Basidiomycetes; (ii) mycorrhizal specificity is correlated with phylogeny; (iii) in sympatry, there is no overlap in mature plant fungal symbionts even if the fungi and the plants are closely related; and (iv) there are geographical patterns to specificity.  相似文献   

6.
A phylogenetic analysis of the family Lemuridae was accomplished using multiple gene partitions and morphological characters. The results of the study suggest that several nodes in the lemurid phylogeny can be robustly resolved; however, the relationships of the species within the genus Eulemur are problematically nonrobust. The genus Varecia is strongly supported as the basal genus in the family. Hapalemur and Lemur catta are strongly supported as sister taxa and together are the sister group to the genus Eulemur. E. mongoz is the most basal species in the genus Eulemur. E. fulvus subspecies form a monophyletic group with three distinct lineages. E. coronatus is strongly supported as the sister taxon to E. macaco. The relationships of E. rubriventer, E. fulvus, and the E. macaco-E. coronatus pair are unresolved. Our combined molecular and morphological analysis demonstrates the lack of influence that morphology has on the simultaneous analysis tree when these two kinds of data are given equal weight. The effects of several extreme weighting schemes (removal of transitions and of third positions in protein-coding regions) and maximum-likelihood analysis were also explored. We suggest that these other forms of inference add little to resolving the problematic relationships of the species in the genus Eulemur.  相似文献   

7.
The phylogenetic relationships and historical biogeography of 10 currently described rainforest skinks in the genus Saproscincus were investigated using mitochondrial protein-coding ND4 and ribosomal RNA 16S genes. A robust phylogeny is inferred using both maximum likelihood and Bayesian analysis, with all inter-specific nodes strongly supported when datasets are combined. The phylogeny supports the recognition of two major lineages (northern and southern), each of which comprises two divergent clades. Both northern and southern lineages have comparably divergent representatives in mid-east Queensland (MEQ), providing further molecular evidence for the importance of two major biogeographic breaks, the St. Lawrence gap and Burdekin gap separating MEQ from southern and northern counterparts respectively. Vicariance associated with the fragmentation and contraction of temperate rainforest during the mid-late Miocene epoch underpins the deep divergence between morphologically conservative lineages in at least three instances. In contrast, one species, Saproscincus oriarus, shows very low sequence divergence but distinct morphological and ecological differentiation from its allopatric sister clade within Saproscincus mustelinus. These results suggest that while vicariance has played a prominent role in diversification and historical biogeography of Saproscincus, divergent selection may also be important.  相似文献   

8.
9.
对最近被Potemkin作为同一种处理的合叶苔属Scapania中东亚分布的三种即细齿合叶苔S. parvidens Steph.、弯瓣合叶苔S. parvitexta Steph.和灰绿合叶苔S. glaucoviridis Horik.的模式标本及相关标本进行了比较研究。结果表明, 它们仍应该作为三个独立不同的种来处理。对三个种的模式标本进行了绘图和描述, 并详细讨论了三种之间的区别。  相似文献   

10.
The aim of this work was to infer the phylogeny of the Greek endemic land-snail genus Codringtonia Kobelt 1898, estimate the time frame of the radiation of the genus, and propose a biogeographic scenario that could explain the contemporary distribution of Codringtonia lineages. The study took place in the districts of Peloponnese, Central Greece and Epirus of mainland Greece. Sequence data originating from three mtDNA genes (COI, COII, and 16S rDNA) were used to infer the phylogeny of the eight nominal Codringtonia species. Furthermore, the radiation time-frame of extant Codringtonia species was estimated using a relaxed molecular clock analysis and mtDNA substitution rates of land snails. The phylogenetic analysis supported the existence of six Codringtonia lineages in Greece and indicated that one nominal species (Codringtonia neocrassa) might belong to a separate genus distantly related to Codringtonia. The time frame of differentiation of Codringtonia species was placed in the Late Miocene-Pleistocene epoch. The dispersal-vicariance analysis performed indicated that most probably Codringtonia exhibited a north-to-south spread with the ancestral area being that of central Greek mainland, accompanied with duplication (speciation) and vicariance events.  相似文献   

11.
The three extant potoroo species of the marsupial genus Potorous -Potorous tridactylus, P. longipes and P. gilbertii - are all of conservation concern due to introduced predators and habitat loss associated with the European settlement of Australia. Robust phylogenies can be useful to inform conservation management, but past phylogenetic studies on potoroos have been unable to fully resolve relationships within the genus. Here, a multi-locus approach was employed, using three mitochondrial DNA (mtDNA): NADH dehydrogenase subunit 2, cytochrome c oxidase subunit 1 and 12S rRNA and four nuclear DNA (nuDNA) gene regions: breast and ovarian cancer susceptibility gene, recombination activating gene-1, apolipoprotein B and omega globin. This was coupled with widespread geographic sampling of the broadly distributed P. tridactylus, to investigate the phylogenetic relationships within this genus. Analyses of the mtDNA identified five distinct and highly divergent lineages including, P. longipes, P. gilbertii and three distinct lineages within P. tridactylus (northern mainland, southern mainland and Tasmanian). P. tridactylus was paraphyletic with the P. gilbertii lineage, suggesting that cryptic taxa may exist within P. tridactylus. NuDNA sequences lacked the resolution of mtDNA. Although they resolved the three currently recognised species, they were unable to differentiate lineages within P. tridactylus. Current management of P. tridactylus as two sub-species (mainland and Tasmania) does not recognise the full scope of genetic diversity within this species, especially that of the mainland populations. Until data from more informative nuDNA markers are available, we recommend this species be managed as the following three subspecies: Potorous tridactylus tridactylus (southern Queensland and northern New South Wales); Potorous tridactylus trisulcatus (southern New South Wales and Victoria) Potorous tridactylus apicalis (Tasmania). Molecular dating estimated that divergences within Potorous occurred in the late Miocene through to the early Pliocene.  相似文献   

12.
Frullania Raddi is an extant genus of liverworts (Bryophytes) widespread around the world. It belongs to the family Frullaniaceae Lorch., with a large number of species distributed into several subgenera, sections and subsections according with different morphological classifications. As shown in previous studies, most Frullania sub-generic classifications are supported by molecular data, indicating that morphological characters appear well suitable to discriminate species. However, deep among-clade relationships remain unclear, probably due to the rapid diversification of main clades, paralleling other plant lineages. In this study, we reconstruct Frullania phylogeny based on available molecular data used in previous studies, and we present time estimates for the origin of its main branches. Results supported the monophyly of most subgenera as demonstrated in previous studies and supported a rapid diversification of these main lineages. Time estimates under a relaxed molecular clock and with integrated fossil evidence and nucleotide mutation rates further suggested a Jurassic origin of the genus and a rapid diversification during Palaeogene and Neogene. This may have been influenced by geographical and climate changes during these periods as predicted for most leafy liverworts.  相似文献   

13.
In order to successfully manage and conserve species and plant communities, it is important to have a good understanding of their ecology and distributions. The three liverwort species Anastrophyllum donnianum, Scapania ornithopodioides and Scapania nimbosa, are restricted to the mixed northern hepatic mat community found in the most oceanic parts of north-western Europe. These species are of conservation concern because they are globally rare with strict environmental requirements and a limited dispersal potential, which makes them vulnerable to disturbance and climate change. In this study we used species distribution modelling to (1) predict their potential distribution in Norway (2) to assess whether they are limited by dispersal or suitable climate, (3) identify which climatic factors are most important in determining their distribution and (4) suggest regions for further field based surveys. Maximum entropy (MaxEnt) models were developed for each species using target-group background data, and five environmental coverage layers. Our results indicate that all three species are limited by dispersal rather than the availability of suitable areas in Norway. In particular, A. donnianum seems to be limited from reaching uncolonised highly suitable areas in northern Norway due to a barrier unsuitable region with insufficient summer rain. S. ornithopodioides is absent from northern Norway despite the presence of highly suitable regions scattered along the coast. The models locate highly suitable areas where conservation measures should be focused when they overlap with known populations. Areas of interest for targeting searches for potentially undiscovered populations are indicated.  相似文献   

14.
Phylogenies can provide valuable information on biotic and abiotic factors associated with speciation. We examined species relationships in Tristerix (Loranthaceae), a genus of 11 species with an Andean distribution from Colombia to Chile. A previous classification divided Tristerix into subgenera Tristerix (two species) and Metastachys (nine species). We tested this classification by generating a molecular phylogeny of the genus using nuclear ribosomal DNA ITS and chloroplast atpB-rbcL intergenic spacer and trnL-F regions. All partitions generally gave congruent trees, thus a combined analysis was conducted. Tristerix was composed of a northern clade (six species) and a southern clade (four species). Tristerix verticillatus and T. penduliflorus (Metastachys) were strongly supported as members of the (southern) subgenus Tristerix clade. Speciation appears to be correlated with the emergence of matorral and cloud forest biomes and is driven by interactions with pollinators and seed dispersers. Tristerix aphyllus is sister to T. corymbosus of the matorral, not to neighboring temperate forest populations, thus rendering the latter species paraphyletic. This ecological speciation event may have occurred in sympatry. Tristerix provides excellent examples of how, during the orography of the Andes, many dynamic and interacting ecological factors have influenced their speciation.  相似文献   

15.
The members of the genus Heterixalus constitute one of the endemic frog radiations in Madagascar. Here we present a complete species-level phylogeny based on DNA sequences (4876 base pairs) of three nuclear and four mitochondrial markers to clarify the phylogenetic relationships among and within all known species of this genus, as well as the phylogenetic position of the monospecific Seychellean Tachycnemis seychellensis. Although the performance to resolve supported clades of Heterixalus species differed among the investigated gene fragments when analyzed separately, we could identify five well-supported species groups within Heterixalus in the combined analysis of all gene fragments. Our data strongly support a Heterixalus-Tachycnemis clade, and indicate the probable monophyly of Heterixalus placed sister to Tachycnemis. However, the diversification of these lineages may have happened in a short interval of time, leading to an unstable placement of Tachycnemis in the single-gene fragment phylogenies. Referring to the hitherto existing classification of Heterixalus, which is predominantly based on chromatic and bioacoustic characters, we examined the relative performance of these data sets relative to our molecular phylogeny. A Bayesian tree reconstructed with a bioacoustic data set yielded a higher resemblance to the molecular phylogeny than a tree constructed using a chromatic data set, which supports the importance of bioacoustic characters for systematic analyses of these anurans.  相似文献   

16.
Voles of the genus Microtus represent one of the most speciose mammalian genera in the Holarctic. We established a molecular phylogeny for Microtus to resolve contentious issues of systematic relationships and evolutionary history in this genus. A total of 81 specimens representing ten Microtus species endemic to Europe as well as eight Eurasian, six Asian and one Holarctic species were sequenced for the entire cytochrome b gene (1140 bp). A further 25 sequences were retrieved from GenBank, providing data on an additional 23, mainly Nearctic, Microtus species. Phylogenetic analysis of these 48 species generated four well-supported monophyletic lineages. The genus Chionomys, snow voles, formed a distinct and well-supported lineage separate from the genus Microtus. The subgenus Microtus formed the strongest supported lineage with two sublineages displaying a close relationship between the arvalis species group (common voles) and the socialis species group (social voles). Monophyly of the Palearctic pitymyid voles, subgenus Terricola, was supported, and this subgenus was also subdivided into two monophyletic species groups. Together, these groupings clarify long-standing taxonomic uncertainties in Microtus. In addition, the "Asian" and the Nearctic lineages reported previously were identified although the latter group was not supported. However, relationships among the main Microtus branches were not resolved, suggesting a rapid and potentially simultaneous radiation of a widespread ancestor early in the history of the genus. This and subsequent radiations discernible in the cytochrome b phylogeny, show the considerable potential of Microtus for analysis of historical and ecological determinants of speciation in small mammals. It is evident that speciation is an ongoing process in the genus and that the molecular data provides a vital insight into current species limits as well as cladogenic events of the past.  相似文献   

17.
The internal classification of genus Anopheles is updated to reflect taxonomic actions published since the classification was last reviewed in 1994. Both formal and informal taxa are included. The classification is intended to aid researchers and students who are interested in analysing species relationships, making group comparisons and testing phylogenetic hypotheses. The genus includes 444 formally named and 40 provisionally designated extant species divided between six subgenera: Anopheles, Cellia, Kerteszia, Lophopodomyia, Nyssorhynchus and Stethomyia. Subgenera Anopheles, Cellia and Nyssorhynchus are subdivided hierarchically into nested informal groups of morphologically similar species that are believed to represent monophyletic lineages based on morphological similarity. Changes to the classification include additional species, eliminated species and changes to the hierarchical organization and composition of supraspecific groups, some as a result of molecular studies.  相似文献   

18.
The diversity of lacertid lizards in Africa is highest in the southern African subcontinent, where over two-thirds of the species are endemic. With eleven currently recognized species, Pedioplanis is the most diverse among the southern African genera. In this study we use 2200 nucleotide positions derived from two mitochondrial markers (ND2 and 16S rRNA) and one nuclear gene (RAG-1) to (i) assess the phylogeny of Pedioplanis and (ii) estimate divergence time among lineages using the relaxed molecular clock method. Individual analyses of each gene separately supported different nodes in the phylogeny and the combined analysis yielded more well supported relationships. We present the first, well-resolved gene tree for the genus Pedioplanis and this is largely congruent with a phylogeny derived from morphology. Contrary to previous suggestions Heliobolus/Nucras are sister to Pedioplanis. The genus Pedioplanis is monophyletic, with P. burchelli/P. laticeps forming a clade that is sister to all the remaining congeners. Two distinct geographic lineages can be identified within the widespread P. namaquensis; one occurs in Namibia, while the other occurs in South Africa. The P. undata species complex is monophyletic, but one of its constituent species, P. inornata, is paraphyletic. Relationships among the subspecies of P. lineoocellata are much more complex than previously documented. An isolated population previously assigned to P. l. pulchella is paraphyletic and sister to the three named subspecies. The phylogeny identifies two biogeographical clades that probably diverged during the mid-Miocene, after the development of the Benguella Current. This probably led to habitat changes associated with climate and, in conjunction with physical barriers (Great Escarpment), contributed towards speciation within the genus Pedioplanis.  相似文献   

19.
Most of the mitochondrial NADH dehydrogenase subunit 5 (ND5) gene and a part of nuclear 28S ribosomal RNA gene were sequenced for 14 species of ground beetles belonging to the genus Leptocarabus. In both the ND5 and the 28S rDNA phylogenetic trees of Leptocarabus, three major lineages were recognized: (1) L. marcilhaci/L. yokoael/Leptocarabus sp. from China, (2) L. koreanus/L. truncaticollis/L. seishinensis/L. semiopacus/L. canaliculatus/L. kurilensis from the northern Eurasian continent including Korea and Hokkaido, Japan, and (3) all of the Japanese species except L. kurilensis. Clustering of the species in the trees is largely linked to their geographic distribution and does not correlate with morphological characters. The species belonging to different species groups are clustered in the same lineages, and those in the same species group are scattered among the different lineages. One of the possible interpretations of the present results would be that morphological transformations independently took place in the different lineages, sometimes with accompanying parallel morphological evolution, resulting in the occurrence of the morphological species belonging to the same species group (= type) in the different lineages.  相似文献   

20.
The phylogeny of morphologically simple algae is problematic due to insufficient morphological characters to aid in distinguishing species and relationships. The problem is further compounded because multiple evolutionary lineages of morphologically similar species occur in most well‐sampled biogeographic locations; therefore, location cannot be used as a proxy for species. The phylogeny of the upright members of the Erythropeltidales is partially clarified by combining molecular data, unialgal culture observations, and worldwide sampling. Our results show that there are several well‐supported lineages within the Erythropeltidales with only two morphologically recognizable taxa at present. The first is the genus Porphyrostromium, with a well‐developed basal crust, which includes two Erythrotrichia species (Porphyrostromium ligulatum comb. nov. and Porphyrostromium pulvinatum comb. nov.). The second is the branched species Erythrotrichia welwitschii (Rupr.) Batters. There are also six strongly supported Erythrotrichia carnea–like lineages. While not completely satisfactory, we propose that one lineage (lineage 2) with samples close to the type locality be designated as E. carnea with a specific isolate as an epitype. The lack of morphology to differentiate the other lineages leads to a taxonomy based solely on gene sequencing and molecular phylogeny, with rbcL sequences differentiating the lineages proposed. We hold off on proposing more species and genera until more data and samples can be gathered.  相似文献   

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