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1.
Abstract The dung beetle genus Phanaeus as currently recognized by Edmonds (1994) consists of 51 species placed in 13 species groups and two subgenera. Here, I examine the phylogeny and biogeography of this genus by analysing the mitochondrial cytochrome oxidase subunit I (530 bp), nuclear large subunit ribosomal RNA (28S, D2 region), and 67 morphological characters for 28 species of Phanaeus. Both maximum parsimony and Bayesian analyses from the combined data yielded well‐resolved trees, although low bootstrap and posterior probability support were found for basal nodes. The phylogenetic hypotheses presented here suggest that the subgenera Phanaeus s.str. and Notiophanaeus should each be elevated to the status of full genus. With the exception of the eucraniine outgroups, the paleano species group of the genus Phanaeus is recovered as sister to all other taxa, including the outgroups Oxysternon, Sulcophanaeus and Coprophanaeus. High bootstrap values and posterior probabilities supported the species groups endymion, tridens and vindex. Biogeographical analyses suggest an ancestral distribution for Phanaeus in the Andes in South America, although numerous dispersal events evidently have produced a complicated biogeographical history.  相似文献   

2.
Ophion Fabricius is a diverse genus of nocturnal ichneumonid wasps (Insecta: Hymenoptera) that is particularly species‐rich in temperate areas, yet has received little taxonomic attention in the Holarctic region, where most species occur. While there have been some attempts to divide Ophion into monophyletic species groups, the vast majority of species have been lumped into a single, paraphyletic group, the O. luteus species group, which is defined only by the lack of characters specific to the other groups. The challenging morphology of this large catch‐all group has limited attempts to subdivide it, and no phylogenetic hypothesis has been proposed for the genus as a whole. In this study, we use DNA sequence data [28S ribosomal RNA (28S), cytochrome oxidase 1 (COI) and internal transcribed spacer 2 (ITS2)] to present the first molecular phylogeny of Ophion. We also describe the secondary structure of ITS2 for the first time in Ichneumonidae, and explore its implications for phylogeny estimation. We define 13 species groups, nine of which were previously considered part of the O. luteus species group s.l. The included species groups are the O. minutus, O. areolaris, O. scutellaris, O. flavidus, O. parvulus, O. slossonae, O. nigrovarius, O. pteridis, O. luteus s.s., and O. obscuratus species groups, along with three groups lacking described species (Species group 1, New Zealand group, Madagascar group). This study provides a framework for future studies of this diverse and morphologically challenging genus.  相似文献   

3.
The subgenus Selenkothuria comprises 12 species of tropical shallow water sea cucumbers that share morphological features, such as rods in the body wall and tube feet, modified tentacles for suspension feeding, and cryptic colours. The taxonomic status of this taxon has been controversial, but currently it is accepted as a subgenus of the genus Holothuria. Phylogenetic analyses of mitochondrial genes [cytochrome c oxidase subunit 1 (COI), 16S RNA] of ten species of Selenkothuria and related subgenera showed the polyphyly of this subgenus; monophyly was rejected by a likelihood ratio test. A geographical split divides the species of this subgenus into three different groups: one Indo‐West‐Pacific (IWP) group and two American groups. The IWP group is more closely related to Holothuria (Semperothuria) cinerascens and to other subgenera such as Roweothuria, Holothuria, and Vaneyothuria, whereas the two American groups are more closely related to each other and to some species of the subgenus Halodeima. These results suggest multiple parallel originations and diversification of ossicle morphology within the subgenus Selenkothuria. The current scheme of subgenera for the genus Holothuria is not supported, suggesting the need for a new classification. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165 , 109–120.  相似文献   

4.
The phylogeny of anopheline mosquitoes (Culicidae: Anophelinae) is re‐examined using morphological data derived from adults, fourth‐instar larvae and pupae. Based on the data set of Sallum et al. (2000), we add some previously missing data and simplify and recode characters to eliminate ambiguities and more accurately reflect homologies, with special emphasis on characters of the male genitalia that provide the main criteria for the subgeneric classification of genus Anopheles. The principal aim of the study is to assess objectively the phylogenetic relationships and classification of two taxa not included by Sallum et al. (2000): Anopheles corethroides, a representative of the Australasian Stigmaticus Group, and An. kyondawensis, an unusual Oriental species whose adult and pupal stages were only recently discovered. The revised data set consists of 167 characters for 66 species representing the three traditionally recognised genera of Anophelinae, the six traditionally accepted subgenera of genus Anopheles and all informal series and most species groups of subgenera Anopheles, Cellia and Nyssorhynchus. The data are analysed using equal weighting (EW) and implied weighting (IW). Analysis under EW generates a strict consensus tree with principal lineages consistent with those reported by Sallum et al. (2000). Analysis under IW supports the monophyly of Anophelinae, the basal position of Chagasia, the monophyly of subgenera Cellia, Kerteszia and Nyssorhynchus, and the sister relationship of Kerteszia + Nyssorhynchus, but otherwise yields relationships that differ significantly in one respect or another from those obtained in all previous analyses of both morphological and molecular data. Subgenus Anopheles is arrayed as a polyphyletic lineage basal to a monophyletic clade comprising the Neotropical Kerteszia + Nyssorhynchus and the Old World Cellia in a sister‐group relationship. Bironella, Lophopodomyia and Stethomyia are firmly nested within subgenus Anopheles, which would nevertheless still be paraphyletic if these taxa were subsumed within it. Anopheles kyondawensis is well supported as the sister group of Bironella + all other Anopheles. Bironella, Stethomyia, An. corethroides and several other Anopheles clades are each strongly supported in a pectinate series of relationships, terminating in the clade comprising subgenera Cellia, Kerteszia and Nyssorhynchus. These relationships and other aspects of the phylogeny are discussed in relation to the formal and informal classification of genus Anopheles.  相似文献   

5.
The subgenera of Wiedemannia are poorly defined and, as such, most recently described species are not assigned to a subgenus or have been assigned to a subgenus without explanation. In this study we perform a molecular phylogenetic analysis to elucidate relationships within the genus Wiedemannia. We sequenced two mitochondrial (cytochrome oxidase c subunit I and cytochrome β) and two nuclear (carbomoylphosphate synthase domain of rudimentary and elongation factor‐1α) gene fragments to reconstruct phylogenetic relationships among the subgenera Chamaedipsia, Eucelidia, Philolutra, Pseudowiedemannia, Roederella and Wiedemannia (s.s.) using both Bayesian inference and maximum likelihood approaches. The genus was found to be monophyletic, but most of the subgenera were not. We propose eliminating the present subgeneric division altogether. Molecular dating using a log‐normal clock model and calibration with fossil species indicated that Wiedemannia diversified about 48 Ma, while there was still land connectivity between Europe and Asia with North America. Wiedemannia has a near‐worldwide distribution apart from the Australasian and Neotropical regions and Antarctica, with greatest species richness in the western Palaearctic, especially the Mediterranean region. Molecular phylogenetics support more recent morphological studies. The subgenera of Wiedemannia are invalid and rejected. Biogeographical data suggest potential hotspots, and the current distribution is discussed.  相似文献   

6.
Phylogenetic relationships between two New World Syrphinae taxa (Diptera, Syrphidae), i.e. the highly diverse genus Ocyptamus and the large genus Toxomerus, were analysed based on molecular characters. The monophyly of both taxa was tested and the taxonomic status of included subgenera and species groups was examined. Toxomerus constitutes the monogeneric tribe Toxomerini with more than 140 described species, while Ocyptamus (tribe Syrphini) is a very diverse genus (over 300 spp.) with multiple recognised subgenera and species groups. Sequence data from three gene regions were used: the mitochondrial protein-coding gene cytochrome c oxidase subunit I (COI) and the nuclear 28S and 18S ribosomal RNA genes. The secondary structure of two expansion segments (D2, D3) of the ribosomal 28S RNA gene is presented for the family Syrphidae and used for the first time in a multiple sequence alignment. Molecular data were analysed using parsimony, maximum likelihood and Bayesian inference. Toxomerus was always recovered as monophyletic within Ocyptamus, and relationships to other New World taxa such as Salpingogaster (Eosalpingogaster) were well-supported. Only the subgenera and species groups of Ocyptamus were consistently recovered as monophyletic lineages, thus the apparent non-monophyly of Ocyptamus demands reclassification of this clade.  相似文献   

7.
Pycnandra (Sapotaceae), the largest endemic genus in New Caledonia, comprises 66 species classified in six subgenera. We tested phylogenetic relationships and a proposed infrageneric classification by sampling 60 species for sequences of nuclear ribosomal DNA (ETS, ITS, RPB2) and plastid DNA (trnH–psbA) and nine morphological characters. Data were analysed with Bayesian inference, parsimony jackknifing and lineage through time. We recovered a phylogenetic tree supporting the recognition of six proposed subgenera (Achradotypus, Leptostylis, Pycnandra, Sebertia, Trouettia and Wagapensia). Because a subgeneric classification is used, the nomenclature will be stable when the members are transferred to Pycnandra. Morphological traits were optimized in the BEAST analysis, adding evidence to earlier work that morphology has limited value for successfully diagnosing groups in Sapotaceae. We confirm a previously suspected case of cryptic species that exhibit the same morphological features and require the same abiotic conditions, but are distantly related in the phylogenetic tree. We detected two possible new cases of cryptic sibling species that might warrant recognition. A slowdown in speciation rate in several genera has been suggested as evidence that New Caledonia was once submerged after rifting from Australia. Plotting lineages through time reveals two important intervals at 7.5–8.6 Ma and present to 1.5 Ma, when net molecular diversification within the genus was zero. This indicates that the genus presently has reached a dynamic equilibrium, providing additional evidence that New Caledonia is an old Darwinian island, being submerged during the Eocene and colonized after re‐emergence c. 37 Ma. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 57–77.  相似文献   

8.
The hyperdiverse genus Sarcophaga Meigen, with about 890 valid species arranged within 169 subgenera, accounts for almost half of the diversity of the subfamily Sarcophaginae. Current phylogenetic hypotheses for this genus are poorly supported or based on small taxon sets, or both. Here, we use molecular data from the genes COI and 28S to reconstruct the phylogeny of Sarcophaga based on the most comprehensive sampling for the group to date: 144 species from 47 subgenera, including representatives from all regional faunas for the first time. Of the total sequences of Sarcophaga used in the present study, 94.7% were newly generated. The secondary structure of the D1–D3 expansion segments of 28S is presented for the first time for the family Sarcophagidae, and is used in a multiple sequence alignment. Branch support and tree resolution increased remarkably through rogue taxa identification and exclusion. Rogue behaviour was explained mostly as a missing data problem. The RogueNaRok web service and the algorithms chkmoves, IterPCR and prunmajor implemented in the computer program TNT were equally good at identifying critical rogue species, but chkmoves and IterPCR also identified rogue clades. Pruning rogues increased the number of monophyletic subgenera in consensus trees from one to six out of 19 subgenera with more than one representative species. Bayesian inference, maximum‐likelihood and parsimony analyses recovered more monophyletic subgenera after the removal of rogue taxa, with parsimony showing the largest improvements in branch support and resolution. Although with low support, Nearctic taxa were found to be the earliest diverging lineages, followed by a subsequent diversification of Old World faunas, which is in agreement with currently available evidence of a New World origin and early diversification of Sarcophaga.  相似文献   

9.
The phylogenetic relationships of the suprageneric groupsof the ichneumonid subfamily Pimplinae (Hymenoptera) are re‐assessedusing 166 morphological and biological characters for 162 species,representing all of the available described genera and subgenera.The cladistic analysis was repeated using abstracted genera, re‐codedfrom the ­initial set of species, as terminal taxa. Thetopology of the resulting cladograms was similar. In the first (primary) analysisseveral genera (including Neotheronia, Itoplectis, Dolichomitus, Dreisbachia, Polysphincta, Oxyrrhexis and Zonopimpla)were not retrieved as monophyletic groups; however, all except thelast were found to be monophyletic in the second analysis. Theseresults suggest that using abstracted taxa may force a ‘falsemonophyly’ on the preselected groups. Thus we reject theuse of such abstractions, preferring instead to use exemplar speciesthat together show much of the variation that occurs within a hypothesizedgenus. Within the Pimplinae three major groupings were recognized,the Delomeristini (including the Perithoini syn. nov.) , thePimplini and the Ephialtini. Within the Pimplini, two generic groupswere recovered, the Xanthopimpla and Pimpla genus‐groups,but a third postulated group, the Theronia genus‐group, wasfound to be paraphyletic. Within the Ephialtini five groups wererecognized, the Pseudopimpla, Alophosternum, Camptotypus, Ephialtes and Sericopimpla genus‐groups.The spider parasitizing complex of genera (the Polysphincta genus‐complex)was found to nest within the Sericopimpla genus‐group confirmingthe placement of Polysphinctini as a synonym of Ephialtini. Problemswith the status of some existing genera are highlighted, but formalnomenclatural changes are not proposed. The ancestral Pimplinaeare hypothesized to have been solitary ectoparasitic idiobiontson weakly concealed immature Hymenoptera. The major radiations withinthe Pimplinae are shown as: (1) a progressive exploitation of cocooned,then weakly cocooned, lepidopterous pupae in the Pimplini leadingto idiobiont endoparasitism; (2) increasing specialization to attackhosts deeply concealed in wood in the Ephialtes genus‐group,and (3) specialization on a variety of cocooned hosts, includingspider egg sacs, leading to koinobiont ectoparasitism of spiders.A brief synopsis of the distribution of the group is given, and somebiogeographical inferences drawn. The group is presumed to haveoriginated and radiated on Laurasia; no evidence for trans‐Antarcticrelationships can be found. © 2002 The LinneanSociety of London, Zoological Journal of the Linnean Society,2002, 136 , 421?485  相似文献   

10.
Sequences from the ribosomal DNA internal transcribed spacer‐2 (ITS‐2) were compared among species of Sargassaceae including the genera Sargassum and Hizikia. Species of different subgenera and sections of Sargassum were used to assess the taxonomic relationships within the genus, especially the subdivisions of the subgenus Bactrophycus. Sequences were aligned in accordance with their common secondary structure. Phylogenetic trees were constructed using neighbor‐joining, maximum likelihood and maximum parsimony methods with three species of Turbinaria as outgroups. The resulting phylogenetic trees showed that the genus Sargassum is divided into three clades corresponding to the subgenera Phyllotrichia, Sargassum and Bactrophycus. This last subgenus is further divided into four distinct groups: a Spongocarpus clade, a Teretia clade, a Hizikia clade, and a Halochloa/ Repentia clade. The position of the section Phyllo‐cystae, excluded from the subgenus Bactrophycus and included within the subgenus Sargassum is once again confirmed by the present study. Current results strongly support the assignation of Hizikia fusiformis to the genus Sargassum. Based on morphological differences and a distinct position in the molecular trees, Hizikia should be recognized as a section in the subgenus Bactrophycus so that Hizikia (Okamura) Yoshida, stat. nov. is proposed. A remarkably low divergence of ITS‐2 sequences was observed for the species in the sections Repentia and Halochloa, suggesting very recent radiation of these species. The subgenus Sargassum is divided into three clades corresponding to the three known sections: Acanthocarpicae, Malacocarpicae and Zygocarpicae, previously recognized by the morphology of receptacles. The position of Sargassum duplicatum, S. carpophyllum, S.yendoi, S. piluliferum and S. patens within the subgenus Sargassum is discussed.  相似文献   

11.
Abstract. We investigated the phylogeny and taxonomy of the Prenolepis genus‐group, a clade of ants we define within the subfamily Formicinae comprising the genera Euprenolepis, Nylanderia, gen. rev. , Paraparatrechina, gen. rev. & stat. nov. , Paratrechina, Prenolepis and Pseudolasius. We inferred a phylogeny of the Prenolepis genus‐group using DNA sequence data from five genes (CAD, EF1αF1, EF1αF2, wingless and COI) sampled from 50 taxa. Based on the results of this phylogeny the taxonomy of the Prenolepis genus‐group was re‐examined. Paratrechina (broad sense) species segregated into three distinct, robust clades. Paratrechina longicornis represents a distinct lineage, a result consistent with morphological evidence; because this is the type species for the genus, Paratrechina is redefined as a monotypic genus. Two formerly synonymized subgenera, Nylanderia and Paraparatrechina, are raised to generic status in order to provide names for the other two clades. The majority of taxa formerly placed in Paratrechina, 133 species and subspecies, are transferred to Nylanderia, and 28 species and subspecies are transferred to Paraparatrechina. In addition, two species are transferred from Pseudolasius to Paraparatrechina and one species of Pseudolasius is transferred to Nylanderia. A morphological diagnosis for the worker caste of all six genera is provided, with a discussion of the morphological characters used to define each genus. Two genera, Prenolepis and Pseudolasius, were not recovered as monophyletic by the molecular data, and the implications of this result are discussed. A worker‐based key to the genera of the Prenolepis genus‐group is provided.  相似文献   

12.
Monacha is the most species‐rich genus of the family Hygromiidae with a centre of diversity in Anatolia. On the basis of the presence or absence of accessory genital appendages, the group was subdivided into three subgenera, Monacha s. str., Paratheba and Metatheba, in the past. We used mitochondrial and nuclear DNA sequences of a representative sample of species 1) to reconstruct the phylogeny of the major lineages of Monacha, 2) to reconstruct the evolution of the accessory genital appendages, and 3) to reconstruct the biogeography of the group. Our results show that the accessory genital appendages upon which the classification of Monacha into subgenera rested so far, that is the appendicula, which is homologous to the dart sac and/or its accessory sac in other helicoid land snails, and the penis retractor muscle, were lost several times independently in different lineages of Monacha. Even among sister species, these characters were found to be variable. Thus, the typologically defined subgenera are para‐ or polyphyletic assemblages. The reconstruction of the biogeographical history indicated an origin of Monacha in Anatolia and the adjacent Caucasus region which is consistent with the observation that most other genera currently included in the subfamily Monachainae are also endemic to this region. Most major Monacha lineages remained restricted to northern Anatolia. Southern Europe was colonized by Monacha s. str., the Aegean region by Aegaeotheba subgen. n., the Crimean Peninsula by Paratheba and the Levant by Platytheba. On the basis of our phylogenetic analyses and testing of alternative hypotheses, we propose to divide Monacha into eight subgenera. We newly delimit the previously proposed subgenera Monacha s. str., Metatheba, Paratheba and Platytheba, and describe Pontotheba subgen. n., Aegaeotheba subgen. n., Trichotheba subgen. n. and Rhytidotheba subgen. n. as new subgenera.  相似文献   

13.
Sarcophaga Meigen is one of the megadiverse genera of true flies, with approximately 850 valid species worldwide. The genus is divided into about 160 subgenera, the validity of a vast majority of which has never been verified using cladistic methods. This paper deals with the mainly Palaearctic subgenus Heteronychia Brauer & Bergenstamm, which comprises 89 species and is thus the largest subunit of Sarcophaga. We performed a cladistic analysis of the group based exclusively on male morphological characters. Parsimony analyses were run on a matrix of 84 characters for 88 species. Species of the subgenera Discachaeta Enderlein and Notoecus Stein were also included in the matrix. A further analysis was carried out using a subset of characters from the terminalia alone (70 characters). The results show that the clade formed by Heteronychia, Discachaeta, and Notoecus is monophyletic, with Discachaeta emerging as polyphyletic whereas Sarcophaga (Notoecus) longestylata Strobl is nested within the Sarcophaga filia‐group. Character states supporting Heteronychia and the few well‐supported species‐groups are discussed in detail. The following synonymies are proposed: Discachaeta = Heteronychia ( syn. nov. ) and Notoecus = Heteronychia ( syn. nov. ). The paper also includes a historical background of the taxon in relation to the classification of the genus Sarcophaga over the past two centuries, as well as a terminological review of the male terminalia, particularly of the distiphallus. © 2013 The Linnean Society of London  相似文献   

14.
The biogeographical history of major groups of bees with worldwide distributions have often been explained through hypotheses based on Gondwanan vicariance or long distance dispersal events, but until recently these hypotheses have been very difficult, if not impossible, to distinguish. New fossil data, comprehensive information on Mesozoic and Cenozoic coastline positions and the availability of phylogenetically informative DNA markers now makes it feasible to test these hypotheses for some groups of bees. This paper presents historical biogeographical analyses of the genus Xylocopa Latreille, based on phylogenetic analyses of species belonging to 22 subgenera using molecular data from two nuclear genes, elongation factor‐1α (EF‐1α) and phosphoenolpyruvate carboxykinase (PEPCK), combined with previously published morphological and mitochondrial data sets. Phylogenetic analyses based on parsimony and likelihood approaches resulted in several groups of subgenera supported by high bootstrap values (>85%): an American group with the Oriental/Palaearctic subgenera Nyctomelitta and Proxylocopa as sister taxa; a geographically diverse group (Xylocopa s.l); and a group consisting of African and Oriental subgenera. The relationships among these three clades and the subgenus Perixylocopa remained unresolved. The Oriental subgenus Biluna was found to be the sister group of all other carpenter bee subgenera included in this study. Using a relaxed molecular clock calibrated using fossil carpenter bees, we show that the major splits in the carpenter bee phylogeny occurred well after the final breakup of Gondwanaland (the separation of South America and Africa, 100 Mya), but before important Miocene fusion events. Ancestral area analysis showed that the genus Xylocopa most likely had an Oriental‐Palaearctic origin and that the present world distribution of Xylocopa subgenera resulted mainly from independent dispersal events. The influence of Pleistocene glaciations on carpenter bee distributions is also discussed. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society, 2002, 77 , 249–266.  相似文献   

15.
Phylogenetic relationships among members of the diving beetle tribe Cybistrini (Coleoptera: Dytiscidae) were inferred from analysis of 47 adult and larval morphological characters and sequences from portions of the genes cytochrome oxidase I (COI) and II (COII), histone III (H3) and wingless. Thirty‐three species of Cybistrini were included, representing all genus‐groups except Regimbartina Chatanay and Megadytes (Bifurcitus) Brinck, and most historically recognized species groups and subgenera used in the tribe. Outgroups include six species from other tribes within Dytiscinae and Lancetinae. Analyses included parsimony analysis of the combined data, likelihood analysis of combined molecular data and partitioned Bayesian analysis of the combined data. Results indicate that Cybistrini is well supported as a monophyletic group. Within the tribe, all currently recognized genus groups were found to be monophyletic with the exception of Onychohydrus Schaum, which is paraphyletic with respect to Austrodytes Watts in the parsimony analysis, but monophyletic in the likelihood and Bayesian analyses, and Cybister sensu stricto, which is paraphyletic with respect to C. (Melanectes) Brinck and C. (Scaphinectes) Ádám in the parsimony analysis or only the latter in the likelihood and Bayesian analyses. Results also suggest that some, but not all, historically recognized species groups or subgenera in the large genus Cybister Curtis are monophyletic, and this is discussed and compared. To improve the classification, the name Sternhydrus Brinck is elevated from subgenus to genus rank ( new status ). Four subgenera in the genus Cybister are recognized: C. (Melanectes) Brinck, C. (Megadytoides) Brinck ( resurrected ), C. (Neocybister) Miller, Bergsten and Whiting ( new subgenus ) and C. (Cybister) Curtis. The following new synonyms are established: Trochalus Dejean ( new synonym ), and ScaphinectesÁdám = Cybister (Cybister) ( new synonym ). The Neotropical species Cybister parvus Trémouilles (not examined) apparently does not fit any historical or currently recognized genus‐group diagnosis in Cybistrini, so it is retained in Cybister but incertae sedis with respect to subgenus. In addition to classification, the evolution of the unique character combinations present in cybistrines are discussed. A key to the adults of genera and subgenera is presented.  相似文献   

16.
Abstract. We investigated phylogenetic relationships of water striders (Hemiptera‐Heteroptera: Gerridae) from the three principal Holarctic genera, Aquarius Schellenberg, Limnoporus Stål and Gerris Fabricius with parsimony analyses of sixty‐six morphological characters and DNA sequences from mitochondrial (cytochrome c oxidase subunit I + II; large mitochondrial ribosomal subunit) and nuclear (elongation factor 1‐alpha) genes. The taxon sampling included all species of Aquarius and Limnoporus, and a dense, near complete, sample of Gerris species with representatives from all subgenera and species groups, and Gigantometra gigas (China) was selected as an outgroup species. A simultaneous analysis of all data sets gave eight equally parsimonious trees, and a strict consensus tree left only a few relationships within Gerris unresolved. While Limnoporus and Gerris each were resolved as monophyletic entities, Aquarius was found to be polyphyletic, because the Nearctic Aquarius remigis‐group, comprising A. remigis (Say), A. amplus (Drake and Harris), A. nyctalis (Drake and Hottes) and A. remigoides Gallant and Fairbairn, was placed as sister group to Gerris, while the Andean Aquarius chilensis (Berg) was sister group to all three genera. Remaining species of Aquarius comprised a sister group to the Gerris + the A. remigis‐group clade. Based on our phylogenetic reconstruction we discuss relationships within and among the three genera, reassess and diagnose species groups, and discuss zoogeographical relationships among all taxa.  相似文献   

17.
The genus Xiphinema constitutes a large group of about 260 species of plant‐ectoparasitic nematodes. The group is polyphagous and distributed almost worldwide. Some of the species of this genus damage agricultural crops by direct feeding on root cells as well as by transmitting nepoviruses. Species discrimination in Xiphinema is complicated by phenotypic plasticity leading to potential misidentification. We conducted nematode surveys in cultivated and natural environments in Spain from 2009 to 2012, from which we identified 20 populations of Xiphinema species morphologically close to the virus‐vector nematode species Xiphinema diversicaudatum, three apomictic populations tentatively identified as species from the complex Xiphinema aceri‐pyrenaicum group, and one population morphologically different from all others that is characterized by a female tail elongate to conical and absence of uterine differentiation. We developed comparative multivariate analyses for these related species by using morphological and morphometrical features together with molecular data from nuclear ribosomal DNA genes [D2‐D3 expansion segments of large ribosomal subunit 28S, internal transcribed spacer 1 (ITS1), and partial small ribosomal subunit (18S)]. The results of multivariate, molecular, and phylogenetic analysis confirmed the morphological hypotheses and allowed the delimitation and discrimination of two new species in the genus described herein as Xiphinema baetica sp. nov. and Xiphinema turdetanensis sp. nov. , and ten known species: Xiphinema adenohystherum, Xiphinema belmontense, Xiphinema cohni, Xiphinema coxi europaeum, Xiphinema gersoni, Xiphinema hispidum, Xiphinema italiae, Xiphinema lupini, Xiphinema nuragicum, and Xiphinema turcicum. Multivariate analyses based on quantitative and qualitative characters and phylogenetic relationships of Xiphinema spp. based on the three molecular ribosomal markers resulted in a partial consensus of these species grouping as nematode populations were maintained for the majority of morphospecies groups (e.g. morphospecies groups 5 and 6), but not in some others (e.g. position of Xiphinema granatum), demonstrating the usefulness of these analyses for helping in the diagnosis and identification of Xiphinema spp. The clade topology of phylogenetic trees of D2‐D3 and partial 18S regions in this study were congruent in supporting the polyphyletic status of some characters, such as the female tail shape and the degree of development of the genital system in species with both genital branches equally developed. This is the most complete phylogenetic study for Xiphinema non‐americanum‐group species. Agreement between phylogenetic trees and some morphological characters (uterine spines, pseudo‐Z organ, and tail shape) was tested by reconstruction of their histories on rDNA‐based trees using parsimony and Bayesian approaches. Thus, integrative taxonomy, based on the combination of multivariate, molecular analyses with morphology, constitutes a new insight into the identification of Xiphinema species. © 2013 The Linnean Society of London  相似文献   

18.
Laparocerus are plant‐chewing flightless weevils distributed on oceanic islands in Macaronesia, with a single species in Morocco. The genus has a complicated taxonomic history with several subgenera described. To assist in a taxonomical revision of the group, a molecular study was undertaken. In this first contribution, the species from the Azores and Madeira archipelagos are studied together with representatives of subgenera from the Canary Islands and the single known continental species (46 OTUs). Phylogenetic analyses are based on sequence data from mitochondrial cytochrome oxidase II (COII) and the ribosomal 16S ribosomal RNA (16S rRNA) genes (combined data set 1023 bp), with additional data from the nuclear elongation factor 1α (EF‐1α) for some selected species. Maximum likelihood (ML) and Bayesian analyses show that all Madeiran species are monophyletic and form a monophyletic group with the Afro‐Canarian samples. Species of the genus Lichenophagus appear within the Madeiran and Canarian Laparocerus clades, but separated in accordance with their respective island origin. Thus, Lichenophagus is here restricted to Madeiran species and proposed as subgenus (status novo) of Laparocerus. Conversely, the Laparocerus subgenus Drouetius from the Azores is revealed to be a separate and distant outgroup, in agreement with its morphological distinctiveness, deserving an independent genus status. Internal relationships within the Madeiran clade are discussed and compared with morphologically defined species groups. The Madeiran monotypic subgenus Cyphoscelis is not supported by the genetic data and synonymized (nov. syn.) with Laparocerus. Subgenera Laparocerus and Atlantis prove to be polyphyletic. Consequently a restriction to monophyletic and morphologically congruent clades is proposed. A cryptic species vicariant of Laparocerus morio was detected and recognized as L. chaoensis, status novo. Other cases of discrepancy between the genetic results and the traditional taxonomy are discussed in detail in the light of mitochondrial introgression, incomplete lineage sorting or poor taxonomy hypotheses.  相似文献   

19.
Simulium is a very speciose genus of the black fly family Simuliidae that includes many important pests of humans and animals. Cytotaxonomic and morphological studies have made substantial progress in Simulium systematics. 16S rRNA and ITS-1 DNA sequence studies have assisted this progress. Intensive multi-gene molecular systematic investigations will, however, be required for a comprehensive understanding of the genus’ taxonomy and evolution. Our research was conducted to investigate the relationships of Thai Simulium at the subgeneric, species group and species levels. We also examined the possibility of using mitochondrial DNA sequences to facilitate Simulium species identification. Data were collected from three mitochondrial genes (COI, ND4 and 16S rRNA) and two segments of the nuclear 28S ribosomal RNA (the D1 to D2 and the D4 expansion regions). The subgenera Simulium and Gomphostilbia were monophyletic in most analyses. Nevermannia included Montisimulium but was otherwise monophyletic in multigene analyses. In most analyses, Simulium and Nevermannia were more closely related to each other than to Gomphostilbia which was usually basal. Species groups were generally monophyletic. Within Gomphostilbia, however, the batoense species group was always paraphyletic to the other two species groups found in Thailand. Three species groups in Simulium were not monophyletic. The tendency to gill filament number reduction for some species groups in the subgenus Simulium was associated with a derived position in multigene analyses. Most species were monophyletic with two exceptions that probably represent species complexes and will present difficulties for rapid mitochondrial DNA identification.  相似文献   

20.
The genus Betula comprises various species in boreal and temperate climate zones of the Northern Hemisphere. The taxonomy of Betula is controversial and complicated by parallel evolution of morphological traits, polyploidization events, and extensive hybridization and introgression among species. Multilocus molecular data from AFLPs were used to provide phylogenetic information. A large number of polymorphic markers (321 variable bands) were produced in 107 Betula accessions from 23 species and 11 hybrids. The AFLP results were largely congruent with the results from previously examined nuclear DNA markers. Four distinct subgenera were identified within the genus Betula. These subgenera were partly in disagreement with the traditional (but disputed) division of the genus. In addition, the results indicated several groups of conspecific taxa. The majority of the species fell within subgenus Betula and shared a high degree of similarity with B. pendula. All hybrids were associated with this group, and the AFLP data contained signals on putative parents for some of the interspecific hybrids. Subgenus Chamaebetula and part of the Neurobetula species should be merged with Betula. The subgenera Betulenta, Betulaster, and the remaining part of Neurobetula are distinct and well supported. Although our results indicate that four major taxonomic groups can be recognized within the genus Betula, the relationship between them remains unclear. This may be due to the occurrence of hybridization and introgression, which would have a homogenizing effect on the relationships between species. Naturally occurring Betula species of hybrid origin may explain the low bootstrap values within the Betula clade. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

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