Evolutionary relationships among basal fungi (Chytridiomycota and Zygomycota): Insights from molecular phylogenetics

Evolutionary relationships of the two basal fungal phyla Chytridiomycota and Zygomycota are reviewed in light of recent molecular phylogenetic investigation based on rDNA (nSSU, nLSU rDNA), entire mitochondrial genomes, and nuclear protein coding gene sequences (e.g., EF-1alpha, RPB1). Accumulated molecular evidence strongly suggests that the two basal fungal phyla are not monophyletic. For example, the chytridiomycete order Blastocladiales appears to be closely related to the zygomycete order Entomophthorales. Within the Zygomycota, a monophyletic clade, consisting of the Dimargaritales, Harpellales, and Kickxellales, which is characterized by a shared unique septal ultrastructure, was identified. Moreover, evidence for the exclusion of zygomycete orders Amoebidiales and Eccrinales from the Fungi, and their placement at the Animal-Fungi boundary has been clearly documented. Microsporidia, a group of amitochondriate organisms currently under intensive study, is not supported as derived within the Fungi, but a fungal affinity cannot be ruled out. Taking these molecular phylogenetic studies into account, we proposed a hypothetical evolutionary framework of basal fungi.     

Group I Introns from Zygomycota: Evolutionary Implications for the Fungal IC1 Intron Subgroup

The origins of fungal group I introns within nuclear small-subunit (nSSU) rDNA are enigmatic. This is partly because they have never been reported in basal fungal phyla (Zygomycota and Chytridiomycota), which are hypothesized to be ancestral to derived phyla (Ascomycota and Basidiomycota). Here we report group I introns from the nSSU rDNA of two zygomycete fungi, Zoophagus insidians (Zoopagales) and Coemansia mojavensis (Kickxellales). Secondary structure analyses predicted that both introns belong to the IC1 subgroup and that they are distantly related to each other, which is also suggested by different insertion sites. Molecular phylogenetic analyses indicated that the IC1 intron of Z. insidians is closely related to the IC1 intron inserted in the LSU rDNA of the basidiomycete fungus Clavicorona taxophila, which strongly suggests interphylum horizontal transfer. The IC1 intron of C. mojavensis has a low phylogenetic affinity to other fungal IC1 introns inserted into site 943 of nSSU rDNA (relative to E. coli 16S rDNA). It is noteworthy that this intron contains a putative ORF containing a His–Cys box motif in the antisense strand, a hallmark for nuclear-encoded homing endonucleases. Overall, molecular phylogenetic analyses do not support the placement of these two introns in basal fungal IC1 intron lineages. This result leads to the suggestion that fungal IC1 introns might have invaded or been transferred laterally after the divergence of the four major fungal phyla. Received: 8 February 2001 / Accepted: 1 November 2001     

Molecular phylogeny of parasitic zygomycota (Dimargaritales, zoopagales) based on nuclear small subunit ribosomal DNA sequences

We analyzed sequence data of the 18S rDNA gene from representatives of nine mycoparasitic or zooparasitic genera to infer the phylogenetic relationships of these fungi within the Zygomycota. Phylogenetic analyses identified a novel monophyletic clade consisting of the Zoopagales, Kickxellales, Spiromyces, and Harpellales. Analyses also identified a monophyletic mycoparasitic-zooparasitic Zoopagales clade in which Syncephalis, Thamnocephalis, and Rhopalomyces form a sister group to a Piptocephalis-Kuzuhaea clade. Although monophyly of the mycoparasitic Dimargaritales received strong bootstrap and decay index support, phylogenetic relationships of this order could not be resolved because of the unusually high rate of base substitutions within the 18S rDNA gene. Overall, the 18S gene tree topology is weak, as reflected by low bootstrap and decay index support for virtually all internal nodes uniting ordinal and superordinal taxa. Nevertheless, the 18S rDNA phylogeny is mostly consistent with traditional phenotypic-based classification schemes of the Fungi.     

Early diverging Ascomycota: phylogenetic divergence and related evolutionary enigmas

The early diverging Ascomycota lineage, detected primarily from nSSU rDNA sequence-based phylogenetic analyses, includes enigmatic key taxa important to an understanding of the phylogeny and evolution of higher fungi. At the moment six representative genera of early diverging ascomycetes (i.e. Taphrina, Protomyces, Saitoella, Schizosaccharomyces, Pneumocystis and Neolecta) have been assigned to "Archiascomycetes" sensu Nishida and Sugi ama (1994) or the subphylum "Taphrinomycotina" sensu Eriksson and Winka (1997). The group includes fungi that are ecologically and morphologically diverse, and it is difficult therefore to define the group based on common phenotypic characters. Bayesian analyses of nSSU rDNA or combined nSSU and nLSU rDNA sequences supported previously published Ascomycota frameworks that consist of three major lineages (i.e. a group of early diverging Ascomycota. [Taphrinomycotina], Saccharomycotina and Pezizomycotina); Taphrinomycotina is the sister group of Saccharomycotina and Pezizomycotina. The 50% majority rule consensus of 18000 Bayesian MCMCMC-generated trees from multilocus gene sequences of nSSU rDNA, nLSU rDNA (D1/D2), RPB2 and beta-tubulin also showed the monophyly of the three subphyla and the basal position of Taphrinomycotina in Ascomycota with significantly higher statistical support. However to answer controversial questions on the origin, monophyly and evolution of the Taphrinomycotina, additional integrated phylogenetic analyses might be necessary using sequences of more genes with broader taxon sampling from the early diverging Ascomycota.     

Assembling the fungal tree of life: progress, classification, and evolution of subcellular traits

Based on an overview of progress in molecular systematics of the true fungi (Fungi/Eumycota) since 1990, little overlap was found among single-locus data matrices, which explains why no large-scale multilocus phylogenetic analysis had been undertaken to reveal deep relationships among fungi. As part of the project "Assembling the Fungal Tree of Life" (AFTOL), results of four Bayesian analyses are reported with complementary bootstrap assessment of phylogenetic confidence based on (1) a combined two-locus data set (nucSSU and nucLSU rDNA) with 558 species representing all traditionally recognized fungal phyla (Ascomycota, Basidiomycota, Chytridiomycota, Zygomycota) and the Glomeromycota, (2) a combined three-locus data set (nucSSU, nucLSU, and mitSSU rDNA) with 236 species, (3) a combined three-locus data set (nucSSU, nucLSU rDNA, and RPB2) with 157 species, and (4) a combined four-locus data set (nucSSU, nucLSU, mitSSU rDNA, and RPB2) with 103 species. Because of the lack of complementarity among single-locus data sets, the last three analyses included only members of the Ascomycota and Basidiomycota. The four-locus analysis resolved multiple deep relationships within the Ascomycota and Basidiomycota that were not revealed previously or that received only weak support in previous studies. The impact of this newly discovered phylogenetic structure on supraordinal classifications is discussed. Based on these results and reanalysis of subcellular data, current knowledge of the evolution of septal features of fungal hyphae is synthesized, and a preliminary reassessment of ascomal evolution is presented. Based on previously unpublished data and sequences from GenBank, this study provides a phylogenetic synthesis for the Fungi and a framework for future phylogenetic studies on fungi.     

Phylogenetic utility of protein (RPB2, β-tubulin) and ribosomal (LSU,SSU) gene sequences in the systematics of Sordariomycetes (Ascomycota,Fungi)

The Sordariomycetes is an important group of fungi whose taxonomic relationships and classification is obscure. There is presently no multi-gene molecular phylogeny that addresses evolutionary relationships among different classes and orders. In this study, phylogenetic analyses with a broad taxon sampling of the Sordariomycetes were conducted to evaluate the utility of four gene regions (LSU rDNA, SSU rDNA, beta-tubulin and RPB2) for inferring evolutionary relationships at different taxonomic ranks. Single and multi-gene genealogies inferred from Bayesian and Maximum Parsimony analyses were compared in individual and combined datasets. At the subclass level, SSU rDNA phylogenies demonstrate their utility as a marker to infer phylogenetic relationships at higher levels. All analyses with SSU rDNA alone, combined LSU rDNA and SSU rDNA, and the combined 28 S rDNA, SSU rDNA and RPB2 datasets resulted in three subclasses: Hypocreomycetidae, Sordariomycetidae and Xylariomycetidae, which correspond well to established morphological classification schemes. At the ordinal level, the best resolved phylogeny was obtained from the combined LSU rDNA and SSU rDNA datasets. Individually, the RPB2 gene dataset resulted in significantly higher number of parsimony informative characters. Our results supported the recent separation of Boliniaceae, Chaetosphaeriaceae and Coniochaetaceae from Sordariales and placement of Coronophorales in Hypocreomycetidae. Microascales was found to be paraphyletic and Ceratocystis is phylogenetically associated to Faurelina, while Microascus and Petriella formed another clade and basal to other members of Halosphaeriales. In addition, the order Lulworthiales does not appear to fit in any of the three subclasses. Congruence between morphological and molecular classification schemes is discussed.     

Phylogeny and origin of 82 zygomycetes from all 54 genera of the Mucorales and Mortierellales based on combined analysis of actin and translation elongation factor EF-1α genes

True fungi (Eumycota) are heterotrophic eukaryotic microorganisms encompassing ascomycetes, basidiomycetes, chytridiomycetes and zygomycetes. The natural systematics of the latter group, Zygomycota, are very poorly understood due to the lack of distinguishing morphological characters. We have determined sequences for the nuclear-encoded genes actin (act) from 82 zygomycetes representing all 54 currently recognized genera from the two zygomycetous orders Mucorales and Mortierellales. We also determined sequences for translation elongation factor EF-1α (tef) from 16 zygomycetes (total of 96,837 bp). Phylogenetic analysis in the context of available sequence data (total 2,062 nucleotide positions per species) revealed that current classification schemes for the mucoralean fungi are highly unnatural at the family and, to a large extent, at the genus level. The data clearly indicate a deep, ancient and distinct dichotomy of the orders Mucorales and Mortierellales, which are recognized only in some zygomycete systems. Yet at the same time the data show that two genera – Umbelopsis and Micromucor – previously placed within the Mortierellales on the basis of their weakly developed columella (a morphological structure of the sporangiophore well-developed within all Mucorales) are in fact members of the Mucorales. Phylogenetic analyses of the encoded amino acid sequences in the context of homologues from eukaryotes and archaebacterial outgroups indicate that the Eumycota studied here are a natural group but provide little or no support for the monophyly of either zygomycetes, ascomycetes or basidiomycetes. The data clearly indicate that a complete revision of zygomycete natural systematics is necessary.     

Phylogenetic relationship within the Erythrobasidium clade: molecular phylogenies, secondary structure, and intron positions inferred from partial sequences of ribosomal RNA and elongation factor-1alpha genes

Phylogenetic relationships within the Erythrobasidium clade as a lineage of the urediniomycetous yeasts were examined using partial regions of 18S rDNA, 5.8S rDNA, 26S rDNA, internal transcribed spacers (ITSs), and elongation factor (EF)-1alpha. Combined data analysis of all segments successfully yielded a reliable phylogeny and confirmed the cohesion of species characterized by Q-10(H2) as a major ubiquinone. Differences in secondary structure predicted for a variable region in 26S rDNA corresponded to major divergences in the phylogenetic tree based on the primary sequence. The common presence of a shortened helix in this region was considered to be evidence of monophyly for species with Q-10(H2), Sakaguchia dacryoides, Rhodotorula lactosa, and Rhodotorula lamellibrachiae, although it was not as strongly supported by the combined data tree. The information on intron positions in the EF-1alpha gene had potential usefulness in the phylogenetic inference between closely related species.     

Molecular phylogeny of the Entomophthoromycota

The Entomophthoromycota is a ubiquitous group of fungi best known as pathogens of a wide variety of economically important insect pests, and other soil invertebrates. This group of fungi also includes a small number of parasites of reptiles, vertebrates (including humans), macromycetes, fern gametophytes, and desmid algae, as well as some saprobic species. Here we report on recent studies to resolve the phylogenetic relationships within the Entomophthoromycota and to reliably place this group among other basal fungal lineages. Bayesian Interference (BI) and Maximum Likelihood (ML) analyses of three genes (nuclear 18S and 28S rDNA, mitochondrial 16S, and the protein-coding RPB2) as well as non-molecular data consistently and unambiguously identify 31 taxa of Entomophthoromycota as a monophyletic group distinct from other Zygomycota and flagellated fungi. Using the constraints of our multi-gene dataset we constructed the most comprehensive rDNA phylogeny yet available for Entomophthoromycota. The taxa studied here belong to five distinct, well-supported lineages. The Basidiobolus clade is the earliest diverging lineage, comprised of saprobe species of Basidiobolus and the undescribed snake parasite Schizangiella serpentis nom. prov. The Conidiobolus lineage is represented by a paraphyletic grade of trophically diverse species that include saprobes, insect pathogens, and facultative human pathogens. Three well supported and exclusively entomopathogenic lineages in the Entomophthoraceae center around the genera Batkoa, Entomophthora and Zoophthora, although several genera within this crown clade are resolved as non-monophyletic. Ancestral state reconstruction suggests that the ancestor of all Entomophthoromycota was morphologically similar to species of Conidiobolus. Analyses using strict, relaxed, and local molecular clock models documented highly variable DNA substitution rates among lineages of Entomophthoromycota. Despite the complications caused by different rates of molecular evolution among lineages, our dating analysis indicates that the Entomophthoromycota originated 405±90million years ago. We suggest that entomopathogenic lineages in Entomophthoraceae probably evolved from saprobic or facultatively pathogenic ancestors during or shortly after the evolutionary radiation of the arthropods.     

A new nuclear gene for insect phylogenetics: dopa decarboxylase is informative of relationships within Heliothinae (Lepidoptera: Noctuidae)

The lack of a readily accessible roster of nuclear genes informative at various taxonomic levels is a bottleneck for molecular systematics. In this report, we describe the first phylogenetic application of the sequence that encodes the enzyme dopa decarboxylase (DDC). For 14 test species within the noctuid moth subfamily Heliothinae that represent the previously best-supported groupings, a 690-bp fragment of DDC resolved relationships that are largely concordant with prior evidence from elongation factor-1 alpha (EF-1 alpha), morphology, and allozymes. Although both synonymous and nonsynonymous changes occur in DDC substantially more rapidly than they do in EF-1 alpha, DDC divergences within Heliothinae are below saturation at all codon positions. Analysis of DDC and EF-1 alpha in combination resulted in increased bootstrap support for several groupings. As a first estimate of previously unresolved relationships, DDC sequences were analyzed from 16 additional heliothines, for a total of 30 heliothine species plus outgroups. Previous relationships based on DDC were generally stable with increased taxon sampling, although a two- to eightfold downweighting of codon position 3 was required for complete concordance with the 14-species result. The weighted strict consensus trees were largely resolved and were congruent with most although not all previous hypotheses based on either morphology or EF-1 alpha. The proposed phylogeny suggests that the major agricultural pest heliothines belong to a single clade, characterized by polyphagy and associated life history traits, within this largely host-specific moth subfamily. DDC holds much promise for phylogenetic analysis of Tertiary-age animal groups.     

Improving phylogenetic inference of mushrooms with RPB1 and RPB2 nucleotide sequences (Inocybe; Agaricales)

Approximately 3000 bp across 84 taxa have been analyzed for variable regions of RPB1, RPB2, and nLSU-rDNA to infer phylogenetic relationships in the large ectomycorrhizal mushroom genus Inocybe (Agaricales; Basidiomycota). This study represents the first effort to combine variable regions of RPB1 and RPB2 with nLSU-rDNA for low-level phylogenetic studies in mushroom-forming fungi. Combination of the three loci increases non-parametric bootstrap support, Bayesian posterior probabilities, and resolution for numerous clades compared to separate gene analyses. These data suggest the evolution of at least five major lineages in Inocybe-the Inocybe clade, the Mallocybe clade, the Auritella clade, the Inosperma clade, and the Pseudosperma clade. Additionally, many clades nested within each major lineage are strongly supported. These results also suggest the family Crepiodataceae sensu stricto is sister to Inocybe. Recognition of Inocybe at the family level, the Inocybaceae, is recommended.     

An evaluation of elongation factor 1 alpha as a phylogenetic marker for eukaryotes

Elongation factor 1 alpha (EF-1 alpha) is a highly conserved ubiquitous protein involved in translation that has been suggested to have desirable properties for phylogenetic inference. To examine the utility of EF-1 alpha as a phylogenetic marker for eukaryotes, we studied three properties of EF-1 alpha trees: congruency with other phyogenetic markers, the impact of species sampling, and the degree of substitutional saturation occurring between taxa. Our analyses indicate that the EF-1 alpha tree is congruent with some other molecular phylogenies in identifying both the deepest branches and some recent relationships in the eukaryotic line of descent. However, the topology of the intermediate portion of the EF-1 alpha tree, occupied by most of the protist lineages, differs for different phylogenetic methods, and bootstrap values for branches are low. Most problematic in this region is the failure of all phylogenetic methods to resolve the monophyly of two higher-order protistan taxa, the Ciliophora and the Alveolata. JACKMONO analyses indicated that the impact of species sampling on bootstrap support for most internal nodes of the eukaryotic EF-1 alpha tree is extreme. Furthermore, a comparison of observed versus inferred numbers of substitutions indicates that multiple overlapping substitutions have occurred, especially on the branch separating the Eukaryota from the Archaebacteria, suggesting that the rooting of the eukaryotic tree on the diplomonad lineage should be treated with caution. Overall, these results suggest that the phylogenies obtained from EF-1 alpha are congruent with other molecular phylogenies in recovering the monophyly of groups such as the Metazoa, Fungi, Magnoliophyta, and Euglenozoa. However, the interrelationships between these and other protist lineages are not well resolved. This lack of resolution may result from the combined effects of poor taxonomic sampling, relatively few informative positions, large numbers of overlapping substitutions that obscure phylogenetic signal, and lineage-specific rate increases in the EF-1 alpha data set. It is also consistent with the nearly simultaneous diversification of major eukaryotic lineages implied by the "big-bang" hypothesis of eukaryote evolution.     

Evolution and phylogenetic utility of alignment gaps within intron sequences of three nuclear genes in bumble bees (Bombus)

To test whether gaps resulting from sequence alignment contain phylogenetic signal concordant with those of base substitutions, we analyzed the occurrence of indel mutations upon a well-resolved, substitution-based tree for three nuclear genes in bumble bees (Bombus, Apidae: Bombini). The regions analyzed were exon and intron sequences of long-wavelength rhodopsin (LW Rh), arginine kinase (ArgK), and elongation factor-1alpha (EF-1alpha) F2 copy genes. LW Rh intron had only a few uninformative gaps, ArgK intron had relatively long gaps that were easily aligned, and EF-1alpha intron had many short gaps, resulting in multiple optimal alignments. The unambiguously aligned gaps within ArgK intron sequences showed no homoplasy upon the substitution-based tree, and phylogenetic signals within ambiguously aligned regions of EF-1alpha intron were highly congruent with those of base substitutions. We further analyzed the contribution of gap characters to phylogenetic reconstruction by incorporating them in parsimony analysis. Inclusion of gap characters consistently improved support for nodes recovered by substitutions, and inclusion of ambiguously aligned regions of EF-1alpha intron resolved several additional nodes, most of which were apical on the phylogeny. We conclude that gaps are an exceptionally reliable source of phylogenetic information that can be used to corroborate and refine phylogenies hypothesized by base substitutions, at least at lower taxonomic levels. At present, full use of gaps in phylogenetic reconstruction is best achieved in parsimony analysis, pending development of well-justified and generally applicable methods for incorporating indels in explicitly model-based methods.     

Analyses of RNA Polymerase II genes from free-living protists: phylogeny,long branch attraction,and the eukaryotic big bang

The phylogenetic relationships among major eukaryotic protist lineages are largely uncertain. Two significant obstacles in reconstructing eukaryotic phylogeny are long-branch attraction (LBA) effects and poor taxon sampling of free-living protists. We have obtained and analyzed gene sequences encoding the largest subunit of RNA Polymerase II (RPB1) from Naegleria gruberi (a heterolobosean), Cercomonas ATCC 50319 (a cercozoan), and Ochromonas danica (a heterokont); we have also analyzed the RPB1 gene from the nucleomorph (nm) genome of Guillardia theta (a cryptomonad). Using a variety of phylogenetic methods our analysis shows that RPB1s from Giardia intestinalis and Trichomonas vaginalis are probably subject to intense LBA effects. Thus, the deep branching of these taxa on RPB1 trees is questionable and should not be interpreted as evidence favoring their early divergence. Similar effects are discernable, to a lesser extent, with the Mastigamoeba invertens RPB1 sequence. Upon removal of the outgroup and these problematic sequences, analyses of the remaining RPB1s indicate some resolution among major eukaryotic groups. The most robustly supported higher-level clades are the opisthokonts (animals plus fungi) and the red algae plus the cryptomonad nm-the latter result gives added support to the red algal origin of cryptomonad chloroplasts. Clades comprising Dictyostelium discoideum plus Acanthamoeba castellanii (Amoebozoa) and Ochromonas plus Plasmodium falciparum (chromalveolates) are consistently observed and moderately supported. The clades supported by our RPB1 analyses are congruent with other data, suggesting that bona fide phylogenetic relationships are being resolved. Thus, the RPB1 gene has apparently retained some phylogenetically meaningful signal, making it worthwhile to obtain sequences from more diverse protist taxa. Additional RPB1 data, especially in combination with other genes, should provide further resolution of branching orders among protist groups within the apparently rapid early divergence of eukaryotes.     

Loss of the flagellum happened only once in the fungal lineage: phylogenetic structure of Kingdom Fungi inferred from RNA polymerase II subunit genes

Background  

At present, there is not a widely accepted consensus view regarding the phylogenetic structure of kingdom Fungi although two major phyla, Ascomycota and Basidiomycota, are clearly delineated. Regarding the lower fungi, Zygomycota and Chytridiomycota, a variety of proposals have been advanced. Microsporidia may or may not be fungi; the Glomales (vesicular-arbuscular mycorrhizal fungi) may or may not constitute a fifth fungal phylum, and the loss of the flagellum may have occurred either once or multiple times during fungal evolution. All of these issues are capable of being resolved by a molecular phylogenetic analysis which achieves strong statistical support for major branches. To date, no fungal phylogeny based upon molecular characters has satisfied this criterion.     

Performance of four ribosomal DNA regions to infer higher-level phylogenetic relationships of inoperculate euascomycetes (Leotiomyceta)

The inoperculate euascomycetes are filamentous fungi that form saprobic, parasitic, and symbiotic associations with a wide variety of animals, plants, cyanobacteria, and other fungi. The higher-level relationships of this economically important group have been unsettled for over 100 years. A data set of 55 species was assembled including sequence data from nuclear and mitochondrial small and large subunit rDNAs for each taxon; 83 new sequences were obtained for this study. Parsimony and Bayesian analyses were performed using the four-region data set and all 14 possible subpartitions of the data. The mitochondrial LSU rDNA was used for the first time in a higher-level phylogenetic study of ascomycetes and its use in concatenated analyses is supported. The classes that were recognized in Leotiomyceta (=inoperculate euascomycetes) in a classification by Eriksson and Winka [Myconet 1 (1997) 1] are strongly supported as monophyletic. The following classes formed strongly supported sister-groups: Arthoniomycetes and Dothideomycetes, Chaetothyriomycetes and Eurotiomycetes, and Leotiomycetes and Sordariomycetes. Nevertheless, the backbone of the euascomycete phylogeny remains poorly resolved. Bayesian posterior probabilities were always higher than maximum parsimony bootstrap values, but converged with an increase in gene partitions analyzed in concatenated analyses. Comparison of five recent higher-level phylogenetic studies in ascomycetes demonstrates a high degree of uncertainty in the relationships between classes.     

基于16S rDNA和28S rDNA D2基因序列与形态特征联合分析的中国角顶叶蝉亚科系统发育研究（半翅目： 叶蝉科）

首次在国内利用28S rDNA D2区段和16S rDNA基因序列,结合50个形态特征对角顶叶蝉亚科(Deltocephalinae)［半翅目（Hemiptera）: 叶蝉科（Cicadellidae）］19个属进行系统发育分析研究。从无水乙醇浸泡保存的标本中提取基因组DNA并扩增了19个内群和1种外群Typhlocybinae［半翅目(Hemiptera): 叶蝉科(Cicadellidae)］种类的28S rDNA D2基因片段并测序,同时扩增了16S rDNA基因片段并测序11条,采用了GenBank中1个种类的16S rDNA同源序列。采用PAUP*4.0和MrBayes3.0两个分析软件和3种建树方法,利用同源28S D2 rDNA和16S rDNA两个基因序列与形态特征结合进行系统发育分析研究。分析结果表明,二叉叶蝉族Macrostelini是一个单系,并在角顶叶蝉亚科的系统发育中处于基部的位置,是内群中最原始的族;角顶叶蝉族Deltocephalini中除了纹翅叶蝉属Nakaharanus,其余各属构成单系;殃叶蝉族Euscelini内属的归属比较混乱,可能是一个并系群,属间差异有待进一步研究。隆额叶蝉族Paralimnini与顶带叶蝉族Athysanini是姐妹群。带叶蝉属Scaphoideus与纹翅叶蝉属Nakaharanus是姐妹群,二者与木叶蝉属Phlogotettix的关系最近,三者构成一个单系,建议将三者归为带叶蝉族Scaphoideini。研究结果还表明,小眼叶蝉族Xestocephalini和Balcluthini的系统发育位置不明,有待进一步研究。     

Phylogenetic relationships of tachinid flies in subfamily Exoristinae (Tachinidae: Diptera) based on 28S rDNA and elongation factor-1α

Abstract The phylogenetic relationships within the largest subfamily of Tachinidae, Exoristinae, were explored using nucleotide sequences of two genes (EF-1α and 28S rDNA). A total of fifty-five and forty-three taxa were represented in the analyses for each gene, respectively, representing forty-three genera. Neighbour joining, parsimony and maximum likelihood inference methods were employed to reconstruct phylogenetic relationships in separate analyses of each gene, and parsimony was used to analyse the combined dataset. Although certain taxa were highly mobile, phylogenetic reconstructions generally supported recent classification schemes based on reproductive habits and genitalia. Generally, the monophyly of Tachinidae and Exoristinae was supported. Tribes Winthemiini, Exoristini and Blondeliini were repeatedly constructed as monophyletic groups, with the former two clades often occupying a basal position among Exoristinae. Goniini and Eryciini generally clustered together as a derived clade within Exoristinae; however, they were never reconstructed as two distinct clades. These results suggest that the possession of unembryonated eggs is plesiomorphic within the subfamily and that there may have been multiple transitions between microtype and macrotype egg forms.