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1.
Twenty strains of flattened amoebae including 17 isolated from fish were characterised morphologically both at light microscopical and ultrastructural levels and assigned to either the genus Vannella Bovee, 1965 or the genus Platyamoeba Page, 1969. Sequence-based phylogenetic analyses of SSU rRNA genes from a data set representing a total of 29 strains of flattened amoebae strongly indicated that morphological features discriminating between these genera do not reflect phylogenetic relationships of representative strains. Contrary to a previous study, strains of this expanded assemblage formed clusters that did not reflect their environmental origin. Monophyletic groups were of mixed origins and contained freshwater as well as marine strains of both genera isolated in geographically distant localities of various continents. These findings were supported by results of phylogenetic analyses of selected strains based on ITS sequences. However, topologies of acquired ITS trees were not congruent with results inferred from SSU rRNA analyses.  相似文献   

2.
The seed morphology of 79 species of neotropical Miconieae (Melastomataceae) is presented. These species have been chosen, in majority, from the polyphyletic genus Leandra. A few other species from the polyphyletic genera Miconia, Ossaea, and Clidemia were also sampled, because of potential similarities. Sixteen morphological seed types are defined after analysis through light microscopy and scanning electron microscopy. The seed morphology appears to possess a great deal of variability on the level of the overall shape as well as the structure and the surface of the testa. The different types defined here do not match with genera or sections, but rather are composed of species coming from different genera. In comparison with a preliminary molecular phylogeny study done on Leandra, some types of seeds are related to well supported clades. In some cases seed morphology corresponds with natural groups of species, thus being of high phylogenetic importance.  相似文献   

3.
4.
Molecular data were used to evaluate the validity of the genus Neopisosoma Haig, 1960. Comparisons of morphological features within Neopisosoma suggest the existence of two lineages, represented among others, by N. angustifrons (Benedict, 1901) and N. neglectum Werding (1986). Both lineages of Neopisosoma are more similar to two morphologically different species groups of the genus Pachycheles, than to congeners of the other group. Comparative morphology of larvae from N. angustifrons, N. neglectum and species of Pachycheles shows that N. angustifrons closely resembles Pachycheles species, whilst N. neglectum is set apart. Sequences of a 465 bp segment of the mitochondrial gene cytochrome oxidase I (COI) were obtained and used to infer phylogenetic relationships among N. angustifrons, N. neglectum, one species of Pachycheles and seven other species of porcellanids, representing three other genera. Results of the molecular analysis were congruent to results of comparative morphological studies of larvae: N. angustifrons grouped with the Pachycheles species, whereas N. neglectum is placed apart. This led us to the conclusion that the genus Neopisosoma is probably paraphyletic and that the criterion used by Haig (1960) is not reliable to define the genus. A revision on a world-wide basis of the genera included, and additional sequence information will be necessary to satisfactorily resolve relationships within the Porcellanidae.  相似文献   

5.
We performed a comparative morphological and molecular study on oxytrichid and urostylid stichotrichs (=part of the former hypotrichs). Included are new small subunit (18S) ribosomal RNA (rRNA) gene sequences from five rare oxytrichids (Gonostomum namibiense, Cyrtohymena citrina, Hemiurosoma terricola, Onychodromopsis flexilis, Orthoamphisiella breviseries) and published sequences, based on cultures provided by the senior author, of two key stichotrichid genera, viz., Gastrostyla and Engelmanniella. These and other sequences, altogether 27 species representing 23 genera, were used to analyze how 18S rRNA-based phylogenetic trees can be reconciled with the morphological and ontogenetical data. In 18S rRNA trees, the oligotrichine family Halteriidae invariably clusters within the oxytrichid clade, usually near Oxytricha granulifera, type species of the genus. This position is hardly supported by morphological and ecological evidence and, especially, it contradicts the current ontogenetic findings; possibly, it is an artifact caused by taxa undersampling and/or special molecular evolutionary events. In contrast, most morphological and DNA sequence data of the stichotrichs can be harmonized with the CEUU (Convergent Evolution of Urostylids and Uroleptids) hypothesis which suggests that the urostylid midventral pattern evolved from an oxytrichine ancestor, developing a second time within the Oxytrichidae. The systematic position of one of the two key genera could be clarified with the 18S rRNA sequences: Gastrostyla is a stylonychine oxytrichid. Based on the molecular data and a reassessment of ontogenesis, a new genus, Styxophrya nov. gen., is established for Onychodromus quadricornutus Foissner, Schlegel & Prescott, 1987.  相似文献   

6.
Ivanova  E. P.  Mikhailov  V. V. 《Microbiology》2001,70(1):10-17
The taxonomic positions of the marine genera Alteromonas, Pseudoalteromonas, Idiomarina, and Colwellia within the gamma subclass of the class Proteobacteria were specified on the basis of their phenotypic, genotypic, and phylogenetic characteristics. Gram-negative aerobic bacteria of the genera Alteromonas, Pseudoalteromonas, and Idiomarina and facultatively anaerobic bacteria of the genus Colwellia were found to form a phylogenetic cluster with a 16S rRNA sequence homology of 90% or higher. The characteristics of these genera presented in this paper allow their reliable taxonomic identification. Based on the analysis of our experimental data and analyses available in the literature, we propose to combine the genera Alteromonas, Pseudoalteromonas, Idiomarina, and Colwellia into a new family, Alteromonadaceae fam. nov., with the type genus Alteromonas.  相似文献   

7.
A new genus and species of deep-water zoarcid fish, Ericandersonia sagamia, is described on the basis of four specimens collected from Sagami Bay, Japan, at depths of 880–930 m. This species is placed in the subfamily Gymnelinae and is distinguished from all genera of gymnelines by the following characters: pseudosubmental crest present; frontals partially fused dorsally; parietals meeting in midline; pelvic fins absent; ventral ramus of posttemporal weak; postorbital head pores 5; pectoral-fin rays 14. The phylogenetic analysis (based on 42 morphological characters) indicates that its position is outside the highly modified (= advanced) genera Seleniolycus, Melanostigma, Puzanovia, Nalbantichthys, Opaeophacus, and Andriashevia.  相似文献   

8.
Plasmopara penniseti is the sole member of the genus Plasmopara parasitic to Poaceae, after the genus Viennotia had been described to accommodate Plasmopara oplismeni. Morphological, ultrastructural, and molecular phylogenetic data indicate that Plasmopara penniseti is not closely related to the generic type, and it is, therefore, transferred to the newly described genus Poakatesthia. The view that the genera of downy mildews with pyriform to vesicular haustoria (Basidiophora, Benua, Bremia, Paraperonospora, Plasmopara, Plasmoverna, and Protobremia) include species parasitic to Poaceae has to be discarded. All of these genera are apparently restricted to dicotyledonous hosts.  相似文献   

9.
The Botiinae have traditionally represented a subfamily of the Cobitidae. At present, the classification and phylogenetic relationships of the Botiinae are controversial. To address systematic and phylogenetic questions concerning this group, we sequenced the complete cytochrome b gene from 34 samples, of which 24 represented 13 species of the East Asian botiine fishes, while the other 10 were non-botiine loach species. For the 1140 bp sequences determined, 494 sites were variable ones, of which 424 were parsimony informative. With Myxocyprinus asiaticus as an outgroup, molecular phylogenetic trees were constructed using the neighbor-joining, maximum parsimony, maximum likelihood and Bayesian methods. All molecular phylogenetic trees revealed that botiine fishes form a monophyletic group and are distantly related to other loaches, suggesting that the Botiinae should be placed in their own family. Within the Botiinae, there are three genera; Botia, Parabotia, andLeptobotia, each genus forming a monophyletic group, with the genus Botia as the most ancestral split. Our molecular results are in agreement with morphological analyses of botiines, suggesting that Botia is the ancestral genus, while Leptobotia and Parabotia were resolved as more derived sister groups.  相似文献   

10.
Recent collections and the type specimen of Marasmiellus juniperinus, the type species of the genus, were examined. Phylogenetic placement, based on ribosomal large subunit (LSU) and internally transcribed spacer (ITS) sequences, is within the lentinuloid clade, nested among Gymnopus taxa. This placement dictates genus name usage and phylogenetic position of other putative species of Marasmiellus. The mating system is tetrapolar.  相似文献   

11.
Most of the species of the family Rubiaceae with flowers arranged in head inflorescences are currently classified in three distantly related tribes, Naucleeae (subfamily Cinchonoideae) and Morindeae and Schradereae (subfamily Rubioideae). Within Morindeae the type genus Morinda is traditionally and currently circumscribed based on its head inflorescences and syncarpous fruits (syncarps). These characters are also present in some members of its allied genera, raising doubts about the monophyly of Morinda. We perform Bayesian phylogenetic analyses using combined nrETS/nrITS/trnT-F data for 67 Morindeae taxa and five outgroups from the closely related tribes Mitchelleae and Gaertnereae to rigorously test the monophyly of Morinda as currently delimited and assess the phylogenetic value of head inflorescences and syncarps in Morinda and Morindeae and to evaluate generic relationships and limits in Morindeae. Our analyses demonstrate that head inflorescences and syncarps in Morinda and Morindeae are evolutionarily labile. Morinda is highly paraphyletic, unless the genera Coelospermum, Gynochthodes, Pogonolobus, and Sarcopygme are also included. Morindeae comprises four well-supported and morphologically distinct major lineages: Appunia clade, Morinda clade (including Sarcopygme and the lectotype M. royoc), Coelospermum clade (containing Pogonolobus and Morinda reticulata), and Gynochthodes–Morinda clade. Four possible alternatives for revising generic boundaries are presented to establish monophyletic units. We favor the recognition of the four major lineages of Morindeae as separate genera, because this classification reflects the occurrence of a considerable morphological diversity in the tribe and the phylogenetic and taxonomic distinctness of its newly delimited genera.  相似文献   

12.
13.
李腾  唐启明  韦玉梅  赵建成  李敏 《广西植物》2021,41(8):1372-1390
通过对采自广西24个县(市)的1 147份青藓科植物标本的逐一鉴定及相关文献的查阅,确认有广西青藓科植物11属、44种,其中包括广西青藓科植物新记录属1属,即拟异叶藓属(Pseudokindbergia),新记录种7种,分别为匐枝青藓(Brachythecium procumbens)、阔叶尖喙藓(Oxyrrhynchium latifolium)、泛生尖喙藓(O. vagans)、拟异叶藓(Pseudokindbergia dumosa)、华东细喙藓(Rhynchostegiella sinensis)、长肋拟青藓(Sciurohypnum populeum)和弯叶拟青藓(S. reflexum)。该文提供了修订后的广西青藓科植物名录,并对其中的新记录属、种的主要形态学识别特征、生境和地理分布等进行了详细描述。  相似文献   

14.
A molecular phylogenetic analysis of Cynoglottis was performed to evaluate previous hypotheses based on non-molecular evidence concerning the position of this genus within Boraginaceae tribe Boragineae. ITS-5.8S and trnLUAA sequences from the nuclear and chloroplast non-coding genomes were obtained for four Cynoglottis taxa and selected members of the related genera Anchusa, Anchusella, Gastrocotyle, Brunnera and Pentaglottis. Cynoglottis is monophyletic, but neither trnL nor ITS support a close relationship with Brunnera, unlike previously supposed on morphological grounds. Brunnera is, instead, related to the southwestern European monotypic genus Pentaglottis, with which it forms a basal clade. ITS-5.8S sequences show that Anchusa thessala, a southeastern European annual species of Anchusa subg. Buglossellum, is sister to Cynoglottis and that the two taxa form a clade which also includes the Balkan endemic Gastrocotyle macedonica. Species of Anchusa subg. Anchusa form a separate lineage with high bootstrap support, suggesting that this heterogeneous genus is paraphyletic with respect to Cynoglottis. ITS sequences also discriminate between the Balkan-Apenninic diploid C. barrelieri and the Anatolian tetraploid C. chetikiana, albeit with low support. The molecular results are discussed in the light of karyological, morphological and chorological aspects.This work has been supported by M.I.U.R. 40% 2003 and the University of Firenze.  相似文献   

15.
The relationship between Litsea and related genera is currently unclear. Previous molecular studies on these taxa using cpDNA and nrITS were unable to produce well-resolved phylogenetic trees. In this study, we explored the potential of the rpb2 gene as a source of molecular information to better resolve the phylogenetic analysis. Although rpb2 was believed to be a single-copy gene, our cloning results showed that most species examined possessed several copies of these sequences. However, the genetic distance among copies from any one species was low, and these copies always formed monophyletic groups in our molecular trees. Our phylogenetic analyses of rpb2 data resulted in better resolved tree topologies compared to those based on cpDNA or nrITS data. Our results show that monophyly of the genus Litsea is supported only for section Litsea. As a genus, Litsea was shown to be polyphyletic. The genera Actinodaphne and Neolitsea were resolved as monophyletic groups in all analyses. They were also shown to be sisters and closer to the genus Lindera than to the genus Litsea. Our results also revealed that the genus Lindera is not a monophyletic group.  相似文献   

16.
The placement of a recently discovered South American monotypic genus,Pseudomonotes tropenbosii, in subfam.Monotoideae (Dipterocarpaceae) extends the geographical range of the subfamily from Africa to the Neotropics. Although morphological and anatomical evidence suggest similarities betweenPseudomonotes andMonotes, the close alliance of these two genera was questionable due to their disjunct distribution and a lack of phylogenetic analysis. In the present study, we reconstructed the phylogeny ofPseudomonotes and other putatively related taxa usingrbcL sequence data. The analysis ofrbcL sequences of 20 taxa belonging to 15 genera and eight families recovered a single most parsimonious tree. The genusSarcolaena (Sarcolaenaceae) formed a clade sister to the monophyleticDipterocarpaceae clade.Monotes andPseudomonotes formed a strongly supported group, sister to the monophyletic clade withPakaraimaea and the remaining Asiatic dipterocarp species studied. The study strongly supports the placement ofPseudomonotes within subfam.Monotoideae of theDipterocarpaceae.  相似文献   

17.
广义无心菜属(Arenaria L.s.l.)是石竹科(Caryophyllaceae)中分类较为困难的大属之一,基于分子系统学研究结果该属目前已被拆分为多属。基于形态学证据,桃色无心菜(Arenaria melandryoides Edgew.)被置于无心菜属齿瓣亚属[subg.Odontostemma (G.Don) Williams]、齿瓣无心菜属(Odontostemma Benth.ex G.Don)或独缀草属[Shivparvatia (Edgew.) PusalkarD.K.Singh]之中,但都缺少分子系统学证据的支持。基于ITS序列重建了繁缕族(Alsineae)系统发育关系,结果表明:目前所界定的齿瓣无心菜属并非单系,桃色无心菜应纳入独缀草属的范畴。此外,还支持将传统无心菜属齿瓣亚属中漆姑无心菜(A.saginoides Maxim.)、匙叶无心菜(A.spathulifolia C.Y.Wu ex L.H.Zhou)及云南无心菜(A.yunnanensis Franch.)归入齿瓣无心菜属的处理,以及将单花亚属中红花无心菜(A.rhodantha PaxK.Hoffmann)归入独缀草属的处理。形态特征上,花朵单生于枝端这一特征可作为独缀草属区别于齿瓣无心菜属的重要识别特征。  相似文献   

18.
Intergeneric crosses were made between representatives of the genomically-defined generaElymus, Agropyron, Elytrigia, Pseudoroegneria, andThinopyrum. The genomic constitution ofElytrigia repens, the type species ofElytrigia, is shown to be SSH, a genomic combination otherwise found only inElymus. The S genome ofPseudoroegneria has almost always a dominant influence on the morphology of the taxa of which it is a component.Wang (1989) showed that the J genome inThinopyrum and the S genome have considerable homoeology, with a mean c-value of 0.35 in diploid SJ hybrids. A genetic coherence from S to SJe, Je, JeJb, and Jb can be expected, agreeing with the continuous morphologic variation pattern observed. Because of the absence of morphological discontinuities between the taxa,Pseudoroegneria (S),Elymus (SH, SY, sometimes with additional genomes),Elytrigia (SSH, SSHX), andThinopyrum (SJ, SJJ, J) are best treated as a single genus,Elymus, following the generic concept ofMelderis in Flora Europaea and Flora of Turkey. The basic genomic constituents ofElymus will then be the S and/or J genomes.Agropyron, with diploids, tetraploids, and hexaploids based on the P genome is morphologically distinct from other genera inTriticeae. In a few species ofElymus andPseudoroegneria, a P genome is an additional constituent. In these cases the P genome has a negligible morphological influence. Therefore, it seems reasonable to maintainAgropyron as a separate genus.  相似文献   

19.
Phylogenetic analyses of the monocotyledonous genera Leucojum and Galanthus (Amaryllidaceae, Asparagales), using plastid (trnL-F and matK) and largely non-coding nuclear ribosomal (ITS) DNA sequences show the two to be closely related to Lapiedra, Narcissus, Vagaria, Pancratium and Sternbergia. We compare the results obtained with a combined parsimony analysis of these nucleotide sequences with that of a matrix of morphological characters. The sampling included all species of Leucojum and most species of Galanthus (representing all series and subseries of the genus) and used as outgroup the above mentioned genera of Amaryllidaceae shown to be close relatives. The plastid, nuclear and morphological data were analysed independently and in combination, showing that the boundaries between the two genera are not appropriate. Galanthus is monophyletic but embedded in Leucojum. On the basis of chromosome numbers and floral characters Leucojum has been previously divided into four subgenera, which have been accepted as genera by some authors. In our phylogenetic analyses (separate as well as combined), Leucojum species are separated in two primary clades corresponding to L. subgenera Ruminia + Acis and L. Leucojum + Aerosperma. The taxonomic implications of this pattern are discussed, and an alternative classification is proposed. Finally, biogeographic relationships of species of both Leucojum and Galanthus are discussed, emphasising the possible origin of the narrowly distributed taxa of Leucojum relative to the widespread species.  相似文献   

20.
The phylogenetic relationships of Peniocereus (Cactaceae) species were studied using parsimony analyses of DNA sequence data. The plastid rpl16 and trnL-F regions were sequenced for 98 taxa including 17 species of Peniocereus, representatives from all genera of tribe Pachycereeae, four genera of tribe Hylocereeae, as well as from three additional outgroup genera of tribes Calymmantheae, Notocacteae, and Trichocereeae. Phylogenetic analyses support neither the monophyly of Peniocereus as currently circumscribed, nor the monophyly of tribe Pachycereeae since species of Peniocereus subgenus Pseudoacanthocereus are embedded within tribe Hylocereeae. Furthermore, these results show that the eight species of Peniocereus subgenus Peniocereus (Peniocereus sensu stricto) form a well-supported clade within subtribe Pachycereinae; P. serpentinus is also a member of this subtribe, but is sister to Bergerocactus. Moreover, Nyctocereus should be resurrected as a monotypic genus. Species of Peniocereus subgenus Pseudoacanthocereus are positioned among species of Acanthocereus within tribe Hylocereeae, indicating that they may be better classified within that genus. A number of morphological and anatomical characters, especially related to the presence or absence of dimorphic branches, are discussed to support these relationships.  相似文献   

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