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1.
Morphology is not a reliable specific indicator in nocturnal animals. Nevertheless, because species are genetically independent, appropriate analytic methods should reveal subtle and consistent morphological differences among them. Until recently, the diversity of living bush babies was underrated, and new species have been recognized on the basis of genetic, behavioral and soft tissue data. This has placed museum curators in a quandary as to how to sort their skin and skull collections according to the new specific designations.We conducted multivariate analyses of 6 morphologically similar pairs of bush baby taxa: Otolemur crassicaudatus and O. garnettii; Galagoides demidoffand G. thomasi; Galago gallarumand G. senegalensis; G. moholi and G. senegalensis; Euoticus elegantulus and E. pallidus, and Galagoides zanzibaricus and G. granti. We also compared subspecies within the taxa Otolemur crassicaudatus, O. garnettii, Galagoides demidoff, and Galago senegalensis. Five out of six species pairs were discriminated with a high level of reliability (88.5–99%) on the basis of 2–5 morphological variables. Only Euoticus elegantulus and E. pallidus did not show this pattern. All strongly supported specific discriminations share two features: (a) ear length is a highly significant factor, while the involvement of other characters is variable; (b) the greater the reliability of the discrimination, the fewer variables necessary to effect it. Euoticus elegantulus and E. pallidus behaved more like subspecies in the discrimination, while Galago senegalensis sspp. showed a pattern of variation similar to that in the specific analyses.  相似文献   

2.
Major aspects of lorisid phylogeny and systematics remain unresolved, despite several studies (involving morphology, histology, karyology, immunology, and DNA sequencing) aimed at elucidating them. Our study is the first to investigate the evolution of this enigmatic group using molecular and morphological data for all four well-established genera: Arctocebus, Loris, Nycticebus, and Perodicticus. Data sets consisting of 386 bp of 12S rRNA, 535 bp of 16S rRNA, and 36 craniodental characters were analyzed separately and in combination, using maximum parsimony and maximum likelihood. Outgroups, consisting of two galagid taxa (Otolemur and Galagoides) and a lemuroid (Microcebus), were also varied. The morphological data set yielded a paraphyletic lorisid clade with the robust Nycticebus and Perodicticus grouped as sister taxa, and the galagids allied with Arctocebus. All molecular analyses maximum parsimony (MP) or maximum likelihood (ML) which included Microcebus as an outgroup rendered a paraphyletic lorisid clade, with one exception: the 12S + 16S data set analyzed with ML. The position of the galagids in these paraphyletic topologies was inconsistent, however, and bootstrap values were low. Exclusion of Microcebus generated a monophyletic Lorisidae with Asian and African subclades; bootstrap values for all three clades in the total evidence tree were over 90%. We estimated mean genetic distances for lemuroids vs. lorisoids, lorisids vs. galagids, and Asian vs. African lorisids as a guide to relative divergence times. We present information regarding a temporary land bridge that linked the two now widely separated regions inhabited by lorisids that may explain their distribution. Finally, we make taxonomic recommendations based on our results.  相似文献   

3.
Bush babies have had a long history of nocturnal life and it would be interesting to know whether their color vision genes have become degenerate. Therefore, we used PCR techniques to sequence the X-linked pigment gene of two of these nocturnal prosimians: Galago senegalensis and Otolemur garnettii. Southern hybridization of genomic DNA of G. senegalensis showed a single X-linked pigment gene. Interestingly, the deduced pigment sequences of the two bush babies are identical. By comparing the X-linked pigments of bush baby, human, squirrel monkey, and marmoset, 38 variable positions were identified. At those positions that may cause a spectral shift, the bush baby pigment has identical or biochemically similar residues to those of the marmoset cone pigment with a spectral peak of 543 nm. This result is consistent with the estimate of 544–545 nm for the spectral peak of the X-linked pigment of Otolemur crassicaudatus, which is closely related to Otolemur garnettii. The neighbor-joining tree of mammalian X-linked pigments showed a significantly shorter branch in the bush baby lineage than in other primate lineages. A relative rate test showed that the nonsynonymous substitution rate of the bush baby X-linked pigment gene is about three times slower than that of the human red pigment gene, though the synonymous substitution rates of the two genes are similar. The slower nonsynonymous rate in the bush baby lineage suggests that the bush baby X-linked pigment gene is under functional constraints, in spite of its nocturnal life. Two radical changes at positions in the intradiskal surface next to the sixth transmembrane domain were observed in the X-linked cone pigment of bush babies but not in other primates. They are changes from Ala to Ser and from Asn to His, which are similar in function to the corresponding residues in rhodopsins. These two changes may be of importance for dim light sensitivity, which is consistent with our proposal that the evolution of the bush baby X-linked pigment gene is under selective pressure. In addition, the 2.5% divergence in introns 2 and 5 of the X-linked pigment gene between the two bush babies supports their classification into two separate genera. Received: 30 November 1996 / Accepted: 17 June 1997  相似文献   

4.
Old World fruitbats were divided into the cynopterine, epomophorine, rousettine, eonycterine, and notopterine sections by Knud Andersen (1912). Among these, the eonycterine and notopterine sections together comprise the subfamily Macroglossinae, which includes forms with specializations for nectarivory. Single-copy DNA hybridization data argue against the monophyly of four of Andersen's sections and further suggest paraphyly or polyphyly of the Macroglossinae. DNA hybridization data provide support for an endemic African clade that includes Megaloglossus (an eonycterine), Epomophorus (an epomophorine), and Lissonycteris (a rousettine). Analyses of mitochondrial 12S rRNA-tRNA valine gene sequences corroborate the African clade but provide less resolution than hybridization data for most branches on the pteropodid tree. Here, we report 11 new 16S rRNA sequences and analyze a mitochondrial data set that includes 12S rRNA, tRNA valine, and 16S rRNA for 18 pteropodid genera. Parsimony, minimum evolution, and maximum likelihood were all employed in phylogenetic analyses. The addition of 16S rRNA sequences to the mitochondrial data set resulted in increased support for several clades, including Macroglossus + Syconycteris, Cynopterus + Thoopterus, Rousettus + the endemic African clade, and Eonycteris + Rousettus + the endemic African clade. Statistical tests suggest that another endemic African genus, Eidolon, is dissociated from the African clade and represents an independent invasion into Africa. We constructed a molecular phylogenetic framework that incorporated clades that were strongly supported by both single-copy DNA hybridization and 12S rRNA-tRNA valine-16S rRNA sequences. Using this framework as a backbone phylogenetic constraint, we then analyzed a morphological data matrix for 34 pteropodid genera with parsimony. Results of this analysis suggest that other epomophorines and Myonycteris (a cynopterine) are also part of the endemic African clade.  相似文献   

5.
We investigated the phylogenetic relationships and estimated the history of species diversification and biogeography in the bufonid genus Ansonia from Southeast Asia, a unique organism with tadpoles adapted to life in strong currents chiefly in montane regions and also in lowland rainforests. We estimated phylogenetic relationships among 32 named and unnamed taxa using 2461 bp sequences of the mitochondrial 12S rRNA, tRNAval, and 16S rRNA genes with equally-weighted parsimony, maximum likelihood, and Bayesian methods of inference. Monophyletic clades of Southeast Asian members of the genus Ansonia are well-supported, allowing for the interpretation of general biogeographic conclusions. The genus is divided into two major clades. One of these contains two reciprocally monophyletic subclades, one from the Malay Peninsula and Thailand and the other from Borneo. The other major clade primarily consists of Bornean taxa but also includes a monophyletic group of two Philippine species and a single peninsular Malaysian species. We estimated absolute divergence times using Bayesian methods with external calibration points to reconstruct the relative timing of faunal exchange between the major landmasses of Southeast Asia.  相似文献   

6.
A phylogenetic analysis of 40 species (22 genera) of the Palaearctic millipede family Julidae was made based on partial sequences of the mitochondrial 16S rRNA (16S) gene and the nuclear 28S rRNA (28S) gene, respectively. The two data sets (16S rDNA and 28S rDNA) were analysed individually and in combination using direct optimization as implemented in POY. The 16S rDNA and the 28S rDNA sequences vary from 410 to 449 bp and from 467 to 525 bp in length, respectively. All searches were performed under six different gap opening costs, an extension gap cost of 1, and a substitution cost of 2. Incongruence length difference values were used to select the preferred tree. The order Julida was recovered as monophyletic under all weight sets. The family Julidae was recovered as monophyletic except under one weight set where the genus Nepalmatoiulus is sister to all other Julida. Within Julidae, a clade of Paectophyllini + Calyptophyllini is sister to all others on the preferred tree but this relationship is not robust. A hitherto unrecognized clade of (South) east Asian genera (Anaulaciulus and Nepalmatoiulus) was recovered under five weight sets. Another “new” robust clade (Oncoiulini + Schizophyllini) is congruent with a hitherto unrecognized complex morphological character. Further clades recovered within the Julidae partly conflict with the accepted classification, which is only to a limited extent based on phylogenetic arguments.  相似文献   

7.
The debated identity of a small forest bushbaby in Malawi is resolved by a short-term field study of the animals’ behavior. Locomotor styles, calling patterns, and the structure of advertising calls confirm that the species is Galago zanzibaricusrather than G. demidoffor G. thomasi.A detailed comparison of acoustic structure between the Malawi animals and G. zanzibaricusin Kenya demonstrates a degree of between-population variation, although the calls remain conservative in those parameters expected to aid recognition of conspecifics. Distribution records extend the known geographical range of G. zanzibaricusover most of the northern half of Malawi. Further studies are required to link the animals from this region with either of the previously recognized subspecies: G. z. zanzibaricusfrom East Africa or G. z. grantifrom southern Malawi, Mozambique, and Zimbabwe.  相似文献   

8.
To more confidently assess phylogenetic relationships among astome ciliates, we obtained small subunit (SSU) rRNA sequences from nine species distributed in six genera and three families: Almophrya bivacuolata, Eudrilophrya complanata, Metaracoelophrya sp. 1, Metaracoelophrya sp. 2, Metaracoelophrya intermedia, Metaradiophrya sp., Njinella prolifera, Paraclausilocola constricta n. gen., n. sp., and Paraclausilocola elongata n. sp. The two new species in the proposed new clausilocolid genus Paraclausilocola n. gen. are astomes with no attachment apparatus, two files of contractile vacuoles, and an arc-like anterior suture that has differentiations of thigmotactic ciliature on the anterior ends of the left kineties of the upper surface. Phylogenetic analyses were undertaken using neighbor-joining, Bayesian inference, maximum likelihood, and maximum parsimony. The nine species of astomes formed a strongly supported clade, showing the subclass Astomatia to be monophyletic and a weakly supported sister clade to the scuticociliates. There were two strongly supported clades within the astomes. However, genera assigned to the same family were found in different clades, and genera assigned to the same order were found in both clades. Thus, astome taxa appear to be paraphyletic when morphology is used to assign species to genera.  相似文献   

9.
Phylogenetic relationships among forty‐nine taxa representing twenty‐four genera of Aphidiinae (Hymenoptera: Braconidae) were investigated using DNA sequence of a portion of the mitochondrial 16S rRNA gene and parsimony analysis. Seven species in six other subfamilies of Braconidae were used as outgroup. The results suggested that members of Aphidiinae are monophyletic. The basal lineage of Aphidiinae was Aclitus in weighted and unweighted parsimony analyses and Praini was basal relative to Ephedrini. With the exception of Pauesia and Aphidius, all genera were monophyletic. The results support generic status for Euaphidius, but not for Lysaphidus. Diaeretus leucopterus was internal to a clade composed of three Pauesia species, suggesting that the latter genus may be paraphyletic. A combined analysis that included DNA sequence of 16S rRNA, NADH1 dehydrogenase and 28S rRNA resulted in more robust cladograms with topologies similar to those inferred from the 16S rRNA gene sequence alone. The results are compared to previously proposed phylogenies of Aphidiinae based on morphological and molecular characters.  相似文献   

10.
The morphologically diverse members of the Laminariales are separated into three families, the Alariaceae, Laminariaceae and Lessoniaceae, on the basis of developmental features exhibited at the stipeblade transition zone. We have investigated the relationships of lessoniacean taxa with those of alariacean and laminariacean affinity. This was done by completing phylogenetic analyses of 3 small-subunit (SSU) rRNA gene (113 bp), first internal transcribed spacer (ITS 1), 5.8S rRNA gene and second internal transcribed spacer (ITS2)(12 bp) sequence data from a variety of taxa. In summary, the Alariaceae and Lessoniaceae are polyphyletic. We present a restricted view of the Alariaceae, including only Alaria and Pterygophora of the genera usually placed in this family, and transfer the monotypic genus Lessoniopsis to this group. Current theories of kelp evolution and biogeography must be reconsidered in view of our data.  相似文献   

11.
We newly sequenced the nuclear-encoded small subunit (SSU) rDNA coding region for 21 taxa of the genus Closterium. The new sequences were integrated into an alignment with 13 known sequences of conjugating green algae representing six traditional families (i.e. Zygnemataceae, Mesotaeniaceae, Gonatozygaceae, Peniaceae, Closteriaceae, and Desmidiaceae) and five known charophycean sequences as outgroups. Both maximum likelihood and maximum parsimony analyses supported with high bootstrap values one large clade containing all placoderm desmids (Desmidiales). All the Closterium taxa formed one clade with 100% bootstrap support, indicating their monophyly, but not paraphyly, as suggested earlier. As to the taxa within the genus Closterium , we found two clades of morphologically closely related taxa in both maximum likelihood and maximum parsimony trees. They corresponded to the C. calosporum species complex and the C. moniliferum-ehrenbergii species complex. It is of particular interest that the homothallic entity of C. moniliferum v. moniliferum was distinguished from and ancestral to all other entities of the C. moniliferum-ehrenbergii species complex. Superimposing all 50 charophycean sequences on the higher order SSU rRNA structure model of Closterium , we investigated degrees of nucleotide conservation at a given position in the nucleotide sequence. A characteristic "signature" structure to the genus Closterium was found as an additional helix at the tip of V1 region. In addition, eight base deletions at the tip of helix 10 were found to be characteristic of the C. calosporum species complex, C. gracile , C. incurvum , C. pleurodermatum , and C. pusillum v. maius. These taxa formed one clade with an 82% bootstrap value in maximum parsimony analysis.  相似文献   

12.
ABSTRACT

The Stilbonematinae are a monophyletic group of marine nematodes that are characterized by a coat of thiotrophic bacterial symbionts. Among the ten known genera of the Stilbonematinae, the genus Robbea Gerlach 1956 had a problematic taxonomic history of synonymizations and indications of polyphyletic origin. Here we describe three new species of the genus, R. hypermnestra sp. nov., R. ruetzleri sp. nov. and R. agricola sp. nov., using conventional light microscopy, interference contrast microscopy and SEM. We provide 18S rRNA gene sequences of all three species, together with new sequences for the genera Catanema and Leptonemella. Both our morphological analyses as well as our phylogenetic reconstructions corroborate the genus Robbea. In our phylogenetic analysis the three species of the genus Robbea form a distinct clade in the Stilbonematinae radiation and are clearly separated from the clade of the genus Catanema, which has previously been synonymized with Robbea. Surprisingly, in R. hypermnestra sp. nov. all females are intersexes exhibiting male sexual characters. Our extended dataset of Stilbonematinae 18S rRNA genes for the first time allows the identification of the different genera, e.g. in a barcoding approach.

http://zoobank.org/urn:lsid:zoobank.org:pub:D37C3F5A-CF2B-40E6-8B09-3C72EEED60B0  相似文献   

13.
Martinsson, S., Kjærandsen, J. & Sundberg, P. (2011). Towards a molecular phylogeny of the fungus gnat genus Boletina (Diptera: Mycetophilidae). —Zoologica Scripta, 40, 272–281. Boletina is a species rich genus of fungus gnats (Diptera: Mycetophilidae) with a mainly Holarctic distribution. The systematics within the genus has gained little attention and this is a first attempt to shed some light over the systematics of Boletina and to test the segregation of the genera Saigusaia and Aglaomyia from Boletina. The nuclear marker 28S and mitochondrial 16S, COI and CytB were amplified and sequenced for 23 taxa that were analysed separately and together with a broad sample of outgroup taxa obtained from GenBank, where also 18S sequences were added. Phylogenies were estimated using maximum likelihood, Bayesian inference and parsimony. We strengthen the hypothesized sister‐group relationship between Docosia and Boletina, but the genus Boletina as currently delimited appears to be paraphyletic and nested in a clade together with Aglaomyia, Coelosia and Gnoriste. The genus Saigusaia, on the other hand, seems to be well separated from Boletina. The Boletina erythropyga species group is consistently found as a distinct basal clade within Boletina s.l. The results obtained are otherwise ambiguous both for the taxa in focus and in some analyses globally with a statistically supported total breakdown of the traditional higher classification into tribes, subfamilies and even families. Interestingly, this breakdown almost disappeared when additional 18S sequences were added.  相似文献   

14.
Jeon, M.‐J., Song, J.‐H. & Ahn, K.‐J. (2012). Molecular phylogeny of the marine littoral genus Cafius (Coleoptera: Staphylinidae: Staphylininae) and implications for classification. —Zoologica Scripta, 41, 150–159. A phylogenetic analysis of the marine littoral genus Cafius Stephens is presented based on molecular characters. The data set comprised partial mitochondrial COI (910 bp), COII (369 bp), 12S rDNA (351–354 bp), 16S rDNA (505–509 bp) and nearly complete sequences of 18S rDNA (1814–1830 bp) for 37 species. Twenty‐seven Cafius species, representing five of six subgenera, two Remus Holme species, three Phucobius Sharp species, monotypic Thinocafius Steel and four outgroups were included. The sequences were analysed simultaneously by parsimony analysis in Tree Analysis Using New Technology (TNT) with traditional manual alignment, direct optimization (DO) in the program POY4 under a variety of gap costs and partitioned Bayesian analysis for the combined data. The genus Cafius and nearly all of its subgenera were not supported as being monophyletic. Instead, all analyses (parsimony trees, DO tree under equal weighting and Bayesian tree) showed monophyly of Cafius + Phucobius + Remus + Thinocafius (clade Z) and all seven nested clades (A–G). However, the phylogenetic relationships among clades A–G differed among the analyses. The genus Phucobius was recovered as a monophyletic group within Cafius. The genus Remus was not monophyletic but formed a clade with C. rufescens Sharp and C. rufifrons Bierig within Cafius. The genus Thinocafius formed a clade with C. caviceps Broun, C. litoreus (Broun) and C. quadriimpressus (White) within Cafius. We propose new concepts for the genus Cafius and its related genera, and the seven nested clades.  相似文献   

15.
Thirty‐one strains of Microcoleus were isolated from desert soils in the United States. Although all these taxa fit the broad definition of Microcoleus vaginatus (Vaucher) Gomont in common usage by soil algal researchers, sequence data for the 16S rRNA gene and 16S–23S internal transcribed spacer (ITS) region indicated that more than one species was represented. Combined sequence and morphological data revealed the presence of two morphologically similar taxa, M. vaginatus and Microcoleus steenstrupii Boye‐Petersen. The rRNA operons of these taxa were sufficiently dissimilar that we suspect the two taxa belong in separate genera. The M. vaginatus clade was most similar to published sequences from Trichodesmium and Arthrospira. When 16S sequences from the isolates we identified as M. steenstrupii were compared with published sequences, our strains grouped with M. chthonoplastes (Mertens) Zanardini ex Gomont and may have closest relatives among several genera in the Phormidiaceae. Organization within the 16S–23S ITS regions was variable between the two taxa. Microcoleus vaginatus had either two tRNA genes (tRNAIle and tRNAAla) or a fragment of the tRNAIle gene in its ITS regions, whereas M. steenstrupii had rRNA operons with either the tRNAIle gene or no tRNA genes in its ITS regions. Microcoleus vaginatus showed no subspecific variation within the combined morphological and molecular characterizations, with 16S similarities ranging from 97.1% to 99.9%. Microcoleus steenstrupii showed considerable genetic variability, with 16S similarities ranging from 91.5% to 99.4%. In phylogenetic analyses, we found that this variability was not congruent with geography, and we suspect that our M. steenstrupii strains represent several cryptic species.  相似文献   

16.
17.
 The genus Hippophae comprises 7 species and 8 subspecies according to the latest classification, and has shown enormous ecological, nutrient and medicinal values. Here we analyzed the phylogenetic relationships among 15 taxa of the genus by comparing sequences of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA (nrDNA). ITS sequences in Hippophae varied in length from 651 bp to 666 bp. The aligned sequences were 690 bp in length and 269 (39.0%) were variable sites with 150 being parsimony-informative. The amount of polymorphism observed within a taxon was extremely low in most taxa except for two putative hybrid species. The aligned sequences were analyzed by maximum parsimony (MP) and neighbor-joining (NJ) methods. In the strict consensus trees of parsimony analysis, the monophyly of Hippophae was supported by 100% bootstrap value. H. tibetana was at the basal position of the genus, and the remaining taxa formed two clades with high bootstrap support. The first clade included subspecies of H.␣rhamnoides and the other one consisted of remaining species. Parsimony analysis also suggested that the species H. tibetana, H. neurocarpa and H.␣salicifolia were all distinct. Although the sequence divergence among subspecies of H. rhamnoides was also remarkably high, the molecular data supported the monophyly of H. rhamnoides when H. rhamnoides subsp. gyantsensis Rousi was excxluded. The NJ trees showed essentially the same topology. The taxonomical arrangement that divided the genus into two sections was not supported based on the ITS sequences. However, the hybrid origin of H. goniocarpa and H. litangensis proposed previously was supported by the present ITS data. Received January 7, 2002; accepted May 10, 2002 Published online: November 22, 2002 Addresses of the authors: Kun Sun, Xuelin Chen, Ruijun Ma, Qin Wang, Institute of Botany, Northwest Normal University, Lanzhou 730070, China. Changbao Li, Song Ge (e-mail: gesong@ns.ibcas.ac.cn or song_ge@hotmail.com), Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.  相似文献   

18.
Members of the family Conopidae (Diptera) have been the focus of little targeted phylogenetic research. The most comprehensive test of phylogenetic support for the present subfamily classification of Conopidae is presented here using 66 specimens, including 59 species of Conopidae and seven outgroup taxa. Relationships among subfamily clades are also explored. A total of 6824 bp of DNA sequence data from five gene regions (12S ribosomal DNA, cytochrome c oxidase subunit I, cytochrome b, 28S ribosomal DNA and alanyl‐tRNA synthetase) are combined with 111 morphological characters in a combined analysis using both parsimony and Bayesian methods. Parsimony analysis recovers three shortest trees. Bayesian analysis recovers a nearly identical tree. Five monophyletic subfamilies of Conopidae are recovered. The rarely acknowledged Zodioninae is restored, including the genera Zodion and Parazodion. The genus Sicus is removed from Myopinae. Morphological synapomorphies are discussed for each subfamily and inter‐subfamily clade, including a comprehensive review of the character interpretaions of previous authors. Included are detailed comparative illustrations of male and female genitalia of representatives of all five subfamilies with new morphological interpretation.  相似文献   

19.
Evolutionary affiliations of eighteen families of Hemiptera (s.l.) are inferred using molecular phylogenetic analysis of nucleotide (nt) sequences of 18S rDNAs. Exemplar taxa include: Archaeorrhyncha (=Fulgoromorpha): flatid, issid, dictyopharid, cixiid and delphacid; Prosorrhyncha (=Heteropterodea): Peloridiomorpha (=Coleorhyncha) -peloridiid, Heteroptera gerrid, lygaeid and mirid; Clypeorrhyncha [=extant (monophyletic) cicadomorphs]: cicadid, cercopoids (cercopid, aphrophorid), membracid and cicadellids (deltocephaline and cicadelline); and Sternorrhyncha: psyllid, aleyrodid, diaspidid and aphid. Analysed sequences encompass a region beginning ?550 nucleotides (nts) from the 5'-end to ?200 nts upstream from the 3'-end of the gene [?1150 base pairs (bp) in euhemipteran to >1400 bp in sternorrhynchan taxa]. Maximum parsimony and bootstrap analyses (PAUP) identify four principal hemipteran clades, Stenorrhyncha, Clypeorrhyncha, Archaeorrhyncha and Prosorrhyncha. These lineages are identified by synapomorphies distributed throughout the gene. Sternorrhyncha is a sister group to all other Hemiptera (i.e. Euhemiptera sensu Zrzavy), rendering Homoptera paraphyletic. Within Euhemiptera, clades Clypeorrhyncha, Archaeorrhyncha, Prosorrhyncha and Heteroptera are supported by one, three, two and three synapomorphic sites, respectively. There is equitable parsimonious inference for Archaeorrhyncha as the sister group to Prosorrhyncha (Neoherriiptera sensu Sorensen et al.) or Clypeorrhyncha, in either case rendering Auchenorrhyncha paraphyletic. Neohemiptera is supported by one synapomorphy. Within Clypeorrhyncha, clade cicada + cercopoids is the sister group of the clade cicadellids + membracid (Membracoidea sensu Dietrich & Deitz). Among archaeorrhynchans, clade delphacid + cixiid is the sister group of the clade dictyopharid + flatid + issid. Within Prosorrhyncha, the peloridiid is sister to the Heteroptera. Within Heteroptera, gerrid is the sister group of the clade mirid + lygaeid (Panheteroptera sensu Schuh). Based on secondary structure of synonymous 18S rRNA, two synapomorphies each of Sternorrhyncha, Prosorrhyncha and Heteroptera are compensatory substitutions on stem substructures. All other synapomorphies identifying major lineages of Hemiptera are noncompensatory substitutions on either bulges or stems. Short basal internodal distances suggest radiation of hemipteran lineages at the suborder level occurred rapidly. Morphological, palaeoentomological and eco-evolutionary factors supporting the 18S rDNA-based phylogenetic tree are discussed.  相似文献   

20.
An unusual species of Geastrum was found growing on decayed wood debris and leaves of Triplochiton scleroxylon in the Mbalmayo Forest Reserve, Cameroon. The species morphologically resembles G. saccatum and G. fimbriatum in having sessile endosperidium partly enclosed by the saccate base of the exoperidium. Microscopically, it is characterized by and distinguished from all other known species of the genus, in having subsmooth, punctate to moderately verruculose, slightly thick-to distinctly thick-walled polymorphous, constricted to eight-shaped, mostly oblong, ovoid, cylindrical, elliptic to clubshaped basidiospores. G. pleosporus was studied from a collection of about fifteen basidiomata covering different stages of development. It is described as new based on morphological analyses and phylogenetic inferences made from large ribosomal DNA sequence alignments. Phylogenetic relationship of G. pleosporus is investigated. In parsimony analyses of partial sequences of the large subunit rDNA from selected Gasteromycetes species, G. pleosporus is closely related to G. saccatum within the strongly supported clade of Geastrum species. The cluster of G. pleosporus and G. saccatum is well supported in parsimony analysis of the dataset with Geastrum species and related taxa using parsimony and maximum likelihood analysis.  相似文献   

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