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1.
The marsupial order Diprotodontia includes 10 extant families, which occupy all terrestrial habitats across Australia and New Guinea and have evolved remarkable dietary and locomotory diversity. Despite considerable attention, the interrelations of these families have for the most part remained elusive. In this study, we separately model mitochondrial RNA and protein-coding sequences in addition to nuclear protein-coding sequences to provide near-complete resolution of diprotodontian family-level phylogeny. We show that alternative topologies inferred in some previous studies are likely to be artifactual, resulting from branch-length and compositional biases. Subordinal groupings resolved herein include Vombatiformes (wombats and koala) and Phalangerida, which in turn comprises Petauroidea (petaurid gliders and striped, feathertail, ringtail and honey possums) and a clade whose plesiomorphic members possess blade-like premolars (phalangerid possums, kangaroos and their allies and most likely, pygmy possums). The topology resolved reveals ecological niche structuring among diprotodontians that has likely been maintained for more than 40 million years.  相似文献   

2.
Phylogenetic relationships within the possums of the family Petauridae, including their affinities with the family Pseudocheiridae, were inferred from DNA sequences obtained for the mitochondrial ND2 gene (1040 bp) combined with previously published partial 12S rDNA sequences. Short, deep internodes characterize some of the divergences obtained. The robustness of these nodes was assessed by several methods such as exclusion of taxa and partitioning of characters. In all analyses a monophyletic Pseudocheiridae was evident, whereas a monophyletic Petauridae was not as well supported. Within the Petauridae, Gymnobelideus was more closely related to Dactylopsila-Dactylonax than to Petaurus. This supports the results obtained from microcomplement fixation of albumin and DNA-DNA hybridization studies but conflicts with morphological data.  相似文献   

3.
Kangaroos and their relatives (family Macropodidae) are divided into the subfamilies Macropodinae (kangaroos, wallabies, pademelons) and Potoroinae (rat-kangaroos, potoroos, bettongs). The musky rat-kangaroo, Hypsiprymnodon moschatus, is traditionally allied with other potoroines, based primarily on the basis of osteological characters and aspects of the female reproductive system. Unlike other macropodids, however, which are capable of bipedal hopping, Hypsiprymnodon is a quadrupedal bounder and lacks several derived features of the pes and tarsus that are presumably adaptations for bipedal hopping. Other derived features, such as a complex stomach, loss of P2 with the eruption of P3, and reduction of litter size to one, are also lacking in Hypsiprymnodon but occur in all other macropodids. Thus, available evidence suggests that Hypsiprymnodon either is part of a monophyletic Potoroinae or is a sister taxon to other living macropodids. To test these hypotheses, we sequenced 1,170 bp base pairs of the mitochondrial genome for 16 macropodids. Maximum parsimony, minimum evolution, maximum likelihood, and quartet puzzling all support the hypothesis that macropodines and potoroines are united to the exclusion of Hypsiprymnodon. This hypothesis implies that characters such as bipedal hopping evolved only once in macropodid evolution. Aside from Hypsiprymnodon, the remaining macropodids separate into the traditional Macropodinae and Potoroinae. Macropodines further separate into two clades: one containing the New Guinean forest wallabies Dorcopsis and Dorcopsulus, and one consisting of the genera Macropus, Setonix, Thylogale, Onychogalea, Wallabia, Dendrolagus, Peradorcas, and Lagorchestes. Among potoroines, there is moderate support for the association of Bettongia and Aepyprymnus to the exclusion of Potorous. Divergence times were estimated by using 12S ribosomal RNA transversions. At the base of the macropodid radiation, Hypsiprymnodon diverged from other macropodids approximately 45 million years ago. This estimate is comparable to divergence estimates among families of Australasian possums based on single-copy DNA hybridization and 12S rRNA transversions. Macropodines and potoroines, in turn, diverged approximately 30 million years ago. Among macropodines, Dorcopsis and Dorcopsulus separated from other taxa approximately 10 million years ago.  相似文献   

4.
As a step towards understanding the higher‐level phylogeny and evolutionary affinities of quadrifid noctuoid moths, we have undertaken the first large‐scale molecular phylogenetic analysis of the moth family Erebidae, including almost all subfamilies, as well as most tribes and subtribes. DNA sequence data for one mitochondrial gene (COI) and seven nuclear genes (EF‐1α, wingless, RpS5, IDH, MDH, GAPDH and CAD) were analysed for a total of 237 taxa, principally type genera of higher taxa. Data matrices (6407 bp in total) were analysed by parsimony with equal weighting and model‐based evolutionary methods (maximum likelihood), which revealed a well‐resolved skeleton phylogenetic hypothesis with 18 major lineages, which we treat here as subfamilies of Erebidae. We thus present a new phylogeny for Erebidae consisting of 18 moderate to strongly supported subfamilies: Scoliopteryginae, Rivulinae, Anobinae, Hypeninae, Lymantriinae, Pangraptinae, Herminiinae, Aganainae, Arctiinae, Calpinae, Hypocalinae, Eulepidotinae, Toxocampinae, Tinoliinae, Scolecocampinae, Hypenodinae, Boletobiinae and Erebinae. Where possible, each monophyletic lineage is diagnosed by autapomorphic morphological character states, and within each subfamily, monophyletic tribes and subtribes can be circumscribed, most of which can also be diagnosed by morphological apomorphies. All additional taxa sampled fell within one of the four previously recognized quadrifid families (mostly into Erebidae), which are now found to include two unusual monobasic taxa from New Guinea: Cocytiinae (now in Erebidae: Erebinae) and Eucocytiinae (now in Noctuidae: Pantheinae).  相似文献   

5.
Trifolium, the clover genus, is one of the largest genera of the legume family. We conducted parsimony and Bayesian phylogenetic analyses based on nuclear ribosomal DNA internal transcribed spacer and chloroplast trnL intron sequences obtained from 218 of the ca. 255 species of Trifolium, representatives from 11 genera of the vicioid clade, and an outgroup Lotus. We confirm the monophyly of Trifolium, and propose a new infrageneric classification of the genus based on the phylogenetic results. Incongruence between the nrDNA and cpDNA results suggests five to six cases of apparent hybrid speciation, and identifies the putative progenitors of the allopolyploids T. dubium, a widespread weed, and T. repens, the most commonly cultivated clover species. Character state reconstructions confirm 2n=16 as the ancestral chromosome number in Trifolium, and infer a minimum of 19 instances of aneuploidy and 22 of polyploidy in the genus. The ancestral life history is hypothesized to be annual in subgenus Chronosemium and equivocal in subgenus Trifolium. Transitions between the annual and perennial habit are common. Our results are consistent with a Mediterranean origin of the genus, probably in the Early Miocene. A single origin of all North and South American species is hypothesized, while the species of sub-Saharan Africa may originate from three separate dispersal events.  相似文献   

6.
The Andes are a cradle of orchid evolution, but most phylogenetic studies of Orchidaceae in this biodiversity hotspot have dealt with epiphytic epidendroid lineages. Here we present a study on neotropical, terrestrial, orchidoid taxa of Prescottiinae s.l. (8 genera, ~100 species), which are adapted to some of the highest elevation habitats on earth that support orchids. They are currently included within an expanded concept of Cranichidinae in the tribe Cranichideae, but DNA sequence data show that neither Prescottiinae s.l. nor Cranichidinae s.s. are monophyletic. Prescottiinae s.l. consist of two strongly supported lineages: the Altensteinia and Prescottia clades, which have closer affinities to Spiranthinae than to Cranichidinae. The Prescottia clade comprises two well-supported subclades, one including most sampled species of Prescottia and a second one with Pseudocranichis thysanochila sister to Prescottia tubulosa. As a group, they are sister to Spiranthinae. Sister to this pair is the Altensteinia clade comprised of six genera, whose intergeneric relationships are well resolved. Finally, Cranichidinae s.s. is sister to all three of these clades. Morphological and ecological features distinguishing the major groups are discussed, as are potential synapomorphies to define them. The reconstructed phylogeny indicates that the classification of Cranichideae needs to be reexamined.  相似文献   

7.
8.
With c. 85 species, the genus Micranthes is among the larger genera of the Saxifragaceae. It is only distantly related to the morphologically similar genus Saxifraga, in which it has frequently been included as Saxifraga section Micranthes. To study the molecular evolution of Micranthes, we analysed nuclear ribosomal (internal transcribed spacer, ITS) and plastid (trnLtrnF) DNA sequences in a comprehensive set of taxa comprising c. 75% of the species. The molecular phylogenetic tree from the combined dataset revealed eight well‐supported clades of Micranthes. These clades agree in part with previously acknowledged subsections or series of Saxifraga section Micranthes. As these eight groups can also be delineated morphologically, we suggest that they should be recognized as sections of Micranthes. New relationships were also detected for some species and species groups, e.g. section Davuricae sister to sections Intermediae and Merkianae, and M. micranthidifolia as a member of section Micranthes. Species proposed to be excluded from the genus Micranthes for morphological reasons were resolved in the molecular tree in Saxifraga. Many morphological characters surveyed were homoplasious to varying extents. Micromorphological characters support comparatively well the clades in the phylogenetic tree. An updated nomenclature and a taxonomic conspectus of sections and species of Micranthes are provided. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 178 , 47–66.  相似文献   

9.
Gary Voelker 《Ibis》2002,144(4):577-584
I used combined sequences of mitochondrial cytochrome  b and ND2 genes to determine the molecular phylogenetic relationships of all five extant species of dipper ( Cinclus ), as well as the relationships of Cinclidae to postulated nearest relatives. All methods of analysis resulted in a single best tree of dipper relationships, uniting the two South American taxa (as sisters) with the single North American exemplar, and the two Eurasian taxa forming a sister clade to the New World taxa. Further, each tree identified thrushes (Turdidae) as the closest relative to Cinclidae. Based on relationships within Cinclus , a Eurasian ancestral area is proposed, with subsequent movement into the New World. Dating of species divergences suggest that dippers arose approximately 4 mya, and achieved their present continental distributions soon after.  相似文献   

10.
A phylogenetic hypothesis for the lizard family Chamaeleonidae is generated from 1503 aligned base positions (883 parsimony-informative) of mitochondrial DNA for specimens representing 59 species (57 ingroup and two outgroup). Sequences are reported for a genomic segment encoding eight transfer RNAs, NADH dehydrogenase component 2 (ND2), and portions of NADH dehydrogenase component 1 (ND1) and cytochrome c oxidase subunit 1 (COI). Newly reported genomic rearrangements and duplications support the hypothesis that mitochondrial gene order and content are destabilized by phylogenetic loss of a functional origin for light-strand replication between the genes encoding tRNA(Asn) and tRNA(Cys). A novel gene order characterizes all sampled Brookesia except B. nasus. Brookesia nasus, the apparent sister taxon of a clade formed by all other Brookesia, has the ancestral gene order but contains a large tandem duplication. An apparently noncoding 220 base pair insertion between the genes encoding ND2 and tRNA(Trp) is reported for Bradypodion tavetanum. Phylogenetic analysis identifies nine clades whose ancestral lineages diverged early in chamaeleonid evolutionary history: (1) Brookesia (possibly excluding B. nasus), (2) Chamaeleo subgenus Chamaeleo (excluding C. namaquensis), (3) Chamaeleo subgenus Trioceros, (4) viviparous Bradypodion, (5) oviparous Bradypodion, (6) genus Furcifer (except F. balteatus), and (7-9) three distinct clades of Calumma. Chamaeleo namaquensis, Brookesia nasus, Furcifer balteatus, Rhampholeon brevicaudatus, and R. spectrum represent ancient lineages dating to approximately the same time. Multiple independent losses and a possible secondary gain of horns are inferred for Trioceros. Viviparity has at least two separate origins in chameleons, one in Bradypodion and  相似文献   

11.
The genus Vanda and its affiliated taxa are a diverse group of horticulturally important species of orchids occurring mainly in South‐East Asia, for which generic limits are poorly defined. Here, we present a molecular study using sequence data from three plastid DNA regions. It is shown that Vanda s.l. forms a clade containing approximately 73 species, including the previously accepted genera Ascocentrum, Euanthe, Christensonia, Neofinetia and Trudelia, and the species Aerides flabellata. Resolution of the phylogenetic relationships of species in Vanda s.l. is relatively poor, but existing morphological classifications for Vanda are incongruent with the results produced. Some novel species relationships are revealed, and a new morphological sectional classification is proposed based on support for these groupings and corresponding morphological characters shared by taxa and their geographical distributions. The putative occurrence of multiple pollination syndromes in this group of taxa, combined with complex biogeographical history of the South‐East Asian region, is discussed in the context of these results. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 549–572.  相似文献   

12.
Molecular phylogenetics of Caenogastropoda (Gastropoda: Mollusca)   总被引:4,自引:0,他引:4  
Caenogastropoda is the dominant group of marine gastropods in terms of species numbers, diversity of habit and habitat and ecological importance. This paper reports the first comprehensive multi-gene phylogenetic study of the group. Data were collected from up to six genes comprising parts of 18S rRNA, 28S rRNA (five segments), 12S rRNA, cytochrome c oxidase subunit I, histone H3 and elongation factor 1alpha. The alignment has a combined length of 3995 base positions for 36 taxa, comprising 29 Caenogastropoda representing all of its major lineages and seven outgroups. Maximum parsimony, maximum likelihood and Bayesian analyses were conducted. The results generally support monophyly of Caenogastropoda and Hypsogastropoda (Caenogastropoda excepting Architaenioglossa, Cerithioidea and Campanilioidea). Within Hypsogastropoda, maximum likelihood and Bayesian analyses identified a near basal clade of nine or 10 families lacking an anterior inhalant siphon, and Cerithiopsidae s.l. (representing Triphoroidea), where the siphon is probably derived independently from other Hypsogastropoda. The asiphonate family Eatoniellidae was usually included in the clade but was removed in one Bayesian analysis. Of the two other studied families lacking a siphon, the limpet-shaped Calyptraeidae was associated with this group in some analyses, but the tent-shaped Xenophoridae was generally associated with the siphonate Strombidae. The other studied hypsogastropods with an anterior inhalant siphon include nine families, six of which are Neogastropoda, the only traditional caenogastropod group above the superfamily-level with strong morphological support. The hypotheses that Neogastropoda are monophyletic and that the group occupies a derived position within Hypsogastropoda are both contradicted, but weakly, by the molecular analyses. Despite the addition of large amounts of new molecular data, many caenogastropod lineages remain poorly resolved or unresolved in the present analyses, possibly due to a rapid radiation of the Hypsogastropoda following the Permian-Triassic extinction during the early Mesozoic.  相似文献   

13.
Members of tribe Vandeae (Orchidaceae) form a large, pantropical clade of horticulturally important epiphytes. Monopodial leafless members of Vandeae have undergone extreme reduction in habit and represent a novel adaptation to the canopy environment in tropical Africa, Asia, and America. To study the evolution of monopodial leaflessness, molecular and structural evidence was used to generate phylogenetic hypotheses for Vandeae. Molecular analyses used sequence data from ITS nrDNA, trnL-F plastid DNA, and matK plastid DNA. Maximum parsimony analyses of these three DNA regions each supported two subtribes within monopodial Vandeae: Aeridinae and a combined Angraecinae + Aerangidinae. Adding structural characters to sequence data resulted in trees with more homoplasy, but gave fewer trees each with more well-supported clades than either data set alone. Two techniques for examining character evolution were compared: (1) mapping vegetative characters onto a molecular topology and (2) tracing vegetative characters onto a combined structural and molecular topology. In both cases, structural synapomorphies supporting monopodial Vandeae were nearly identical. A change in leaf morphology (usually reduced to a nonphotosynthetic scale), monopodial growth habit, and aeration complexes for gas exchange in photosynthetic roots seem to be the most important characters in making the evolutionary transition to leaflessness.  相似文献   

14.
The Afrotropical fruit fly genus Ceratitis MacLeay is an economically important group that comprises over 89 species, subdivided into six subgenera. Cladistic analyses of morphological and host use characters have produced several phylogenetic hypotheses for the genus. Only monophyly of the subgenera Pardalaspis and Ceratitis (sensu stricto) and polyphyly of the subgenus Ceratalaspis are common to all of these phylogenies. In this study, the hypotheses developed from morphological and host use characters are tested using gene trees produced from DNA sequence data of two mitochondrial genes (cytochrome oxidase I and NADH-dehydrogenase subunit 6) and a nuclear gene (period). Comparison of gene trees indicates the following relationships: the subgenus Pardalaspis is monophyletic, subsection A of the subgenus Pterandrus is monophyletic, the subgenus Pterandrus may be either paraphyletic or polyphyletic, the subgenus Ceratalaspis is polyphyletic, and the subgenus Ceratitis s. s. might not be monophyletic. In addition, the genera Ceratitis and Trirhithrum do not form reciprocally monophyletic clades in the gene trees. Although the data statistically reject monophyly for Trirhithrum under the Shimodaira-Hasegawa test, they do not reject monophyly of Ceratitis.  相似文献   

15.
The melyrid lineage of beetles form a distinct group of the superfamily Cleroidea with a high level of soft‐bodiedness. Here we present the first molecular phylogenetic analysis of this group. The data matrix included partial sequences of the small and large subunits of rRNA, the mitochondrial large subunit rRNA, and cytochrome oxidase subunit I of 67 melyrid and eight outgroup taxa. The concatenated sequences were analysed using maximum‐parsimony (MP), maximum‐likelihood (ML) and Bayesian analysis (BA) approach. The results strongly supported the monophyly of the melyrid lineage splitting into six major clades: Rhadalidae, Mauroniscidae, Prionoceridae, Melyridae sensu stricto, Dasytidae and Malachiidae. The rhadalids were placed in the most basal position, followed by mauroniscids and prionocerids. Three terminal lineages—the true melyrids, dasytids, and malachiids—are well supported by all analyses, but their mutual relationships remain uncertain as MP analysis proposed alternative topologies to that of the ML and BA trees, with often low node support in the latter two methods. The monophyly of the subfamily Danacaeinae (Dasytidae) with respect to the danacaeine genera of the southern hemisphere (Hylodanacaea, Listrocerus, Amecocerus) was challenged as they were found to be polyphyletic. Similarly, the monophyly of Attalus was rejected by our analyses and shown to be polyphyletic. Based on the preferred phylogenetic hypothesis, the subfamilies Rhadalinae, Dasytinae and Malachiinae are elevated to family rank. © The Willi Hennig Society 2011.  相似文献   

16.
The plastid matK gene, trnL/F spacer, and nuclear rDNA ITS were sequenced for 36 species of Leontodon and 29 taxa of related genera of tribe Lactuceae. Phylogenetic relationships inferred from the independent and combined data are largely congruent and reveal that Leontodon sensu lato (s.l.) as presently defined is diphyletic: L. subgenus Leontodon forms a clade with Helminthotheca, Picris and Hypochaeris as sister genera, whereas L. subgenus Oporinia appears as a separate clade with strong bootstrap support and is thus better treated as a separate genus. Previous sectional classifications of Leontodon s.l. are considered in the light of DNA and additional morphological and karyological data. Support is presented for a core group of Hypochaeridinae sensu stricto (s.s.) with the two clades of Leontodon s.l., Helminthotheca, Picris, and Hypochaeris, whereas Urospermum, Hyoseris, Aposeris, and Rhagadiolus appear to be positioned more distantly.  相似文献   

17.
Montane areas in the Neotropics are characterized by high diversity and endemism of birds and other groups. The avian genus Myioborus (Parulinae) is a group of insectivorous warblers, characteristic of cloud forests, that represents one of the few Parulinae genera (New World warblers) that has radiated substantially in South America. The genus is distributed throughout most montane regions from the southwestern United States to northern Argentina. Here, I use mitochondrial sequences from the cytochrome b, ND2, and ND3 genes to present the first hypothesis of phylogenetic relationship among all Myioborus species level taxa. Phylogenetic reconstructions based on maximum parsimony, maximum likelihood, and Bayesian methods produced similar results and suggest a northern origin for the genus Myioborus with subsequent colonization of the Neotropical Montane Region. The lower-montane species, M. miniatus, is the sister taxon to a clade in which all taxa occupy upper-montane habitats. These "highland" taxa diverged early in the history of the genus and produced two well-defined monophyletic lineages, a Central-northern Andean clade formed by M. albifrons, M. ornatus, and M. melanocephalus, and a Pantepui (table-mountains of southern Venezuela, northern Brazil, and western Guyana) clade consisting of M. castaneocapillus, M. albifacies, and M. cardonai, and probably M. pariae. M. brunniceps, M. flavivertex, and M. torquatus were included in this upper-montane clade but without clear relationships to other taxa. Lack of resolution of nodes defining the upper-montane species clade is likely to result from a period of rapid diversification mediated by geological and climatic events during the Late Pliocene. These results suggest that an interplay of dispersal and vicariance has shaped the current biogeographic patterns of Myioborus.  相似文献   

18.
Portulaca is the only genus in Portulacaceae and has ca. 100 species distributed worldwide, mainly in the tropics and subtropics. Molecular data place the genus as one of the closest relatives of Cactaceae, but phylogenetic relationships within Portulaca are barely known. This study samples 59 species of Portulaca, 10 infraspecific taxa, and three cultivars, including multiple samples of widespread species. The sampled taxa represent all subgenera in the classifications of von Poellnitz (1934), Legrand (1958), and Geesink (1969) and come from around the world. Nuclear ITS and chloroplast ndhF, trnT-psbD intergenic spacer, and ndhA intron DNA sequences were analyzed using maximum likelihood and Bayesian methods to produce a hypothesis of relationships within Portulaca. Divergence times were estimated using Hawaiian endemics for calibration, and biogeographical patterns were examined using a Bayes-DIVA approach. In addition, the evolution of chromosome numbers in the genus was investigated using probabilistic models. The analyses strongly support the monophyly of Portulaca, with an age of the most recent common ancestor (MRCA) of 23 Myr. Within Portulaca are two major lineages: the OL clade (comprising opposite-leaved species) distributed in Africa, Asia, and Australia, and the AL clade (comprising alternate to subopposite-leaved species), which is more widespread and originated in the New World. Sedopsis, a genus sometimes recognized as distinct from Portulaca based on a long corolla tube, is nested within the OL clade and does not merit taxonomic recognition. Samples of Portulaca grandiflora, Portulaca halimoides, and Portulaca oleracea were found to be non-monophyletic. It is hypothesized that the ancestral distribution area of Portulaca included southern hemisphere continents and Asia. The OL clade remained restricted to the Old World (except Portulaca quadrifida, a pantropical weed), while the AL clade, with a South American origin, was able to disperse multiple times to other continents. The base chromosome number for Portulaca is inferred to be x=9, although the analysis was primarily based on the available data for the AL clade. A number of chromosome number change events (polyploidization, demi-polyploidization, gain, and loss) were shown to have occurred in the genus, especially within the Oleracea clade.  相似文献   

19.
Of 12 brush-tailed possums (Trichosurus vulpecula) inoculated with Leptospira interrogans serovar balcanica 11 developed migroagglutination (MA) antibody to jardjo antigen by 14 days postincubation (PI). Leptospiruria was observed in 2 possums 117 to 145 days PI. Of 6 possums inoculated with serovar hardjo 4 developed low short-lived titres by day 18 PI. Two of 3 wombats (Vombatus ursinus) inoculated with balcanica had high MA titres (greater than or equal to 1:128) by day 16 PI and leptospiruria occurred by day 16. One wombat inoculated with hardjo developed a low MA titre. Low transitory MA titres to hardjo were found in 1 of 3 water rats (Hydromys chrysogaster) after inoculation with balcanica and 1 of 2 given hardjo. Histopathological examination of kidneys revealed mild to moderately severe focal interstitial nephritis in 4 of 8 possums, in 2 wombats and in 2 water rats following experimental infection with balcanica. Similar lesions were observed in 2 of 4 possums, 1 wombat and 2 water rats following experimental infection with hardjo.  相似文献   

20.
The fern genus Dryopteris (Dryopteridaceae) is represented in the Hawaiian Islands by 18 endemic taxa and one non-endemic, native species. The goals of this study were to determine whether Dryopteris in Hawai'i is monophyletic and to infer the biogeographical origins of Hawaiian Dryopteris by determining the geographical distributions of their closest living relatives. We sequenced two chloroplast DNA fragments, rbcL and the trnL-F intergenic spacer (IGS), for 18 Hawaiian taxa, 45 non-Hawaiian taxa, and two outgroup species. For individual fragments, we estimated phylogenetic relationships using Bayesian inference and maximum parsimony. We performed a combined analysis of both cpDNA fragments employing Bayesian inference, maximum parsimony, and maximum likelihood. These analyses indicate that Hawaiian Dryopteris is not monophyletic, and that there were at least five separate colonizations of the Hawaiian Islands by different species of dryopteroid ferns, with most of the five groups having closest relatives in SE Asia. The results suggest that one colonizing ancestor, perhaps from SE Asia, gave rise to eight endemic taxa (the glabra group). Another colonizing ancestor, also possibly from SE Asia, gave rise to a group of five endemic taxa (the exindusiate group). Dryopteris fusco-atra and its two varieties, which are endemic to Hawai'i, most likely diversified from a SE Asian ancestor. The Hawaiian endemic Nothoperanema rubiginosum has its closest relatives in SE Asia, and while the remaining two species, D. wallichiana and D. subbipinnata, are sister species, their biogeographical origins could not be determined from these analyses due to the widespread distributions of D. wallichiana and its closest non-Hawaiian relative.  相似文献   

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