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The phylogenetic position of aglaspidids, a problematic group of Lower Palaeozoic arthropods of undetermined affinities, is re‐examined in the context of the major Cambrian and Ordovician lamellipedian arthropod groups. A cladistic analysis of ten genera of aglaspidids sensu stricto, six aglaspidid‐like arthropods and 42 Palaeozoic arthropod taxa indicates that Xenopoda, Cheloniellida, Aglaspidida sensu lato and Trilobitomorpha form a clade (Artiopoda Hou and Bergström, 1997 ) nested within the mandibulate stem‐lineage, thus discarding previous interpretations of these taxa as part 'of the chelicerate stem‐group (Arachnomorpha Heider, 1913 ). The results confirm an aglaspidid identity for several recently described arthropods, including Quasimodaspis brentsae, Tremaglaspis unite, Chlupacaris dubia, Australaglaspis stonyensis and an unnamed Ordovician Chinese arthropod. The problematic Bohemian arthropod Kodymirus vagans was recovered as sister taxon to Beckwithia typa, and both form a small clade that falls outside Aglaspidida sensu stricto, thus discarding eurypterid affinities for the former. The analysis does not support the phylogenetic position of Kwanyinaspis maotianshanensis at the base of Conciliterga as proposed in recent studies, but rather occupies a basal position within Aglaspidida sensu lato. The results indicate a close association of aglaspidid arthropods with xenopods (i.e. Emeraldella and Sidneyia) and cheloniellids (e.g. Cheloniellon, Duslia); the new clade “Vicissicaudata” is proposed to encompass these arthropods, which are characterized by a differentiated posterior region. The phylogenetic position of aglaspidid arthropods makes them good outgroup candidates for analysing the internal relationships within the groups that form Trilobitomorpha. This work provides a much clearer picture of the phylogenetic relationships among Lower Palaeozoic lamellipedians.  相似文献   

3.
A morphology‐based phylogenetic analysis of the tribe Empoascini (Hemiptera: Cicadellidae: Typhlocybinae) is presented for 58 of 83 formerly recognized genera based on 99 morphological characters of adults. The results support excluding the New World Beamerana generic group from Empoascini. The remaining genera of Empoascini were recovered as a monophyletic sister group of Dikraneurini. Previously recognized tribes Jorumini and Helionini are derived from within Empoascini and are considered synonyms of the latter tribe. Three previously recognized informal generic groups, the Empoasca group, Alebroides group and Usharia group were paraphyletic but the Ficiana group was recovered as monophyletic based on five synapomorphies. Genera previously placed in the Alebroides group represent at least six independent lineages, indicating that the hind wing character separating this group from the Empoasca group (CuA and MP veins free) is highly homoplasious. Empoasca (sensu lato) is also paraphyletic. Thus, twelve previously recognized subgenera of Empoasca are elevated to genus status and five species groups of Empoasca from the New World are recognized as separate new genera. Sikkimasca Dworakowska, 1993 is treated as synonym of Marolda Dworakowska, 1977 based on the phylogeny. Biogeographic analysis suggests that Empoascini most likely first evolved in the Oriental region and spread to other biogeographic realms more recently by multiple independent invasions.  相似文献   

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Legume subfamily Caesalpinioideae accommodates approximately 2250 species in 171 genera which traditionally are placed in four tribes: Caesalpinieae, Cassieae, Cercideae and Detarieae. The monophyletic tribe Detarieae includes the Amherstieae subclade which contains about 55 genera. Our knowledge of the relationships among those genera is good in some cases but for many other genera phylogenetic relationships have been unclear. The non-monophyletic nature of at least two amherstioid genera, Cynometra and Hymenostegia has also complicated the picture. During the course of a multi-disciplinary study of Hymenostegia sensu lato, which includes phylogenetic analyses based on matK and trnL data, we have recovered the “Scorodophloeus clade”, an exclusively tropical African clade of four genera which includes the eponymous genus Scorodophloeus, two undescribed generic segregates of Hymenostegia sensu lato, and the previously unsampled rare monospecific genus Micklethwaitia from Mozambique. Zenkerella is suggested as a possible sister genus to the Scorodophloeus clade. A distribution map is presented of the seven species that belong to the Scorodophloeus clade.  相似文献   

5.
A new genus belonging to the braconid wasp subfamily Doryctinae, Kauriphanes n. gen. (type species K. khalaimi n. sp.), is described from New Zealand. This genus is placed within the doryctine subtribe Caenophanina. The extent of this subtribe is discussed and the phylogenetic relationships of three of its genera were investigated using one mitochondrial and one nuclear DNA sequence markers. Similar to previous studies, the Bayesian analyses performed significantly support a clade with the included members of Caenophanina as a sister group of a clade with the examined species of Spathiini sensu stricto. The placement of the Caenophanini within Doryctini, however, is left pendant to further exhaustive phylogenetic studies. A key to genera and subgenera belonging to Caenophanina is given.  相似文献   

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Nucleotide sequences of the plastidmatK gene and nuclear rDNA internal transcribed spacer region were sampled fromAstragalus L. (Fabaceae), and its closest relatives within tribe Galegeae, to infer phylogenetic relationships and estimate ages of diversification. Consistent with previous studies that emphasized sampling for nrDNA ITS primarily within either New World or Old World species groups,Astragalus, with the exception of a few morphologically distinct species, is strongly supported as monophyletic based on maximum parsimony and Bayesian analyses ofmatK sequences as well as a combined sequence dataset. ThematK data provides better resolution and stronger clade support for relationships amongAstragalus and traditionally related genera than nrDNA ITS.Astragalus sensu stricto plus the genusOxytropis are strongly supported as sister to a clade composed of strictly Old World (African, Australasian) genera such asColutea. Sutherlandia, Lessertia, Swainsona, andCarmichaelia, plus several morphologically distinct segregates of EurasianAstragalus. Ages of these clades and rates of nucleotide substitution estimated from a fossil-constrained, rate-smoothed, Bayesian analysis ofmatK sequences sampled from Hologalegina indicateAstragalus diverged from its sister group,Oxtropis, 12–16 Ma, with divergence of Neo-Astragalus beginning ca 4.4. Ma. Estimates of absolute rates of nucleotide substitution forAstragalus and sister groups, which range from 8.9 to 10.2×10−10 substitutions per site per year, are not unusual when compared to those estimated for other, mainly temperate groups of papilionoid legumes. The results of previously published work and other recent developments on the phylogenetic relationships and diversification ofAstragalus are reviewed.  相似文献   

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Phylogenetic relationships and lineage diversification of the family Salicaceae sensu lato (s.l.) remain poorly understood. In this study, we examined phylogenetic relationships between 42 species from six genera based on the complete plastomes. Phylogenetic analyses of 77 protein coding genes of the plastomes produced good resolution of the interrelationships among most sampled species and the recovered clades. Of the sampled genera from the family, Flacourtia was identified as the most basal and the successive clades comprised both Itoa and Poliothyrsis, Idesia, two genera of the Salicaceae sensu stricto (s.s.) (Populus and Salix). Five major subclades were recovered within the Populus clade. These subclades and their interrelationships are largely inconsistent with morphological classifications and molecular phylogeny based on nuclear internal transcribed spacer sequence variations. Two major subclades were identified for the Salix clade. Molecular dating suggested that species diversification of the major subclades in the Populus and Salix clades occurred mainly within the recent Pliocene. In addition, we found that the rpl32 gene was lost and the rps7 gene evolved into a pseudogene multiple times in the sampled genera of the Salicaceae s.l. Compared with previous studies, our results provide a well‐resolved phylogeny from the perspective of the plastomes.  相似文献   

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Abstract. The dorylomorph group of ants comprises the three subfamilies of army ants (Aenictinae, Dorylinae, Ecitoninae) together with the subfamilies Aenictogitoninae, Cerapachyinae, and Leptanilloidinae. We describe new morphological characters and synthesize data from the literature in order to present the first hypothesis of phylogenetic relationships among all dorylomorph genera. These data include the first available character information from the newly discovered male caste of Leptanilloidinae. We used ant taxa from Leptanillinae, Myrmeciinae, and the poneromorph (Ponerinae sensu lato) subfamilies Amblyoponinae, Ectatomminae, and Paraponerinae as outgroups. We scored a total of 126 characters from twenty-two terminal taxa and used these data to conduct maximum parsimony and bootstrap analyses. The single most-parsimonious tree and bootstrap results support a single origin of army ants. The Old World army ant genus Dorylus forms a monophyletic group with the enigmatic genus Aenictogiton, which is currently known only from males; the second Old World army ant genus Aenictus is sister to this clade. This result generates the prediction that females of Aenictogiton, when discovered, will be observed to possess the army ant syndrome of behavioural and reproductive traits. The monophyly of the New World army ants (Ecitoninae) is supported very strongly, and within this group the genera Eciton, Nomamyrmex, and Labidus form a robust clade. The monophyly of Leptanilloidinae is also upheld. The subfamily Cerapachyinae appears paraphyletic, although this conclusion is not supported by strong bootstrap results. Relationships among genera of Cerapachyinae similarly are not resolved robustly, although parsimony results suggest clades consisting of (Acanthostichus + Cylindromyrmex) and (Cerapachys + Sphinctomyrmex). We tested for the effect of incompletely known taxa by conducting a secondary analysis in which the two genera containing ∼50% missing character data (Aenictogiton and Asphinctanilloides) were removed. The strict consensus of the seventeen most-parsimonious trees from this secondary analysis is poorly resolved outside the army ants and contains no clades conflicting with the primary analysis. The position of Leptanilla shifts from forming the sister group to Leptanilloidinae (without high bootstrap support) in the primary analysis, to falling within a polytomy at the base of the root of the dorylomorphs when incompletely known taxa are removed. This instability suggests that the placement of Leptanilla within the dorylomorphs in our primary analysis may be spurious.  相似文献   

11.
Generic concepts in the economically important agarophyte red algal family Gracilariaceae were evaluated based on maximum parsimony, Bayesian likelihood, and minimum evolution analyses of the chloroplast‐encoded rbc L gene from 67 specimens worldwide. The results confirm the monophyly of the family and identify three large clades, one of which corresponds to the ancestral antiboreal genera Curdiea and Melanthalia, one to Gracilariopsis, and one to Gracilaria sensu lato, which contains nine distinct independent evolutionary lineages, including Hydropuntia. The species currently attributed to Hydropuntia comprise a single well‐supported clade composed of two distinct lineages. The two most basal clades within Gracilaria sensu lato deserve generic rank: a new genus centered around G. chilensis Bird, McLachlan et Oliveira and G. aff. tenuistipitata Chang et Xia and a resurrected Hydropuntia encompassing primarily Indo‐Pacific (G. urvillei [Montagne] Abbott, G. edulis [S. Gmelin] P. Silva, G. eucheumatoides Harvey, G. preissiana [Sonder] Womersley, and G. rangiferina [Kützing] Piccone) and western Atlantic species (G. cornea J. Agardh, G. crassissima P. et H. Crouan in Mazé et Schramm, G. usneoides [C. Agardh] J. Agardh, G. caudata J. Agardh, and G. secunda P. et H. Crouan in Mazé et Schramm). Cystocarpic features within the Gracilaria sensu lato clades appear to be more phylogenetically informative than male characters. The textorii‐type spermatangial configuration is represented in two distinct clusters of Gracilaria. The rbc L genetic divergence among the Gracilariaceae genera ranged between 8.46% and 16.41%, providing at least 2.5 times more genetic variation than does the 18S nuclear rDNA. rbc L also resolves intrageneric relationships, especially within Gracilaria sensu lato. The current number of gracilariacean species is underestimated in the western Atlantic because of convergence in habit and apparent homoplasy in vegetative and reproductive anatomy.  相似文献   

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《Ostrich》2013,84(4):288-294
The taxonomy of, and phylogenetic relationships among, African canaries typically assigned to the genus Serinus sensu lato (including the putative genera Alario, Pseudochloroptila, Serinops, Ochrospiza, Dendrospiza and Crithagra) were investigated, based on 823bp of the mitochondrial cytochrome b gene. Two clades emerged: (1) Palaearctic and Afrotropical taxa, including Serinus serinus, S. canaria, A. alario and the S. canicollis complex (S. c. canicollis, thompsonae and flavivertex), and (2) taxa endemic to the Afrotropics comprising Pseudochloroptila, Serinops, Ochrospiza, Poliospiza, Dendrospiza, Poliospiza and Crithagra spp. However, only clade one has jackknife and bootstrap support values above 50. The two clades were separated by Carduelis taxa, suggesting that Serinus sensu lato is not monophyletic. As it stands, the phylogeny does not support the recognition of Alario and Serinops and possibly Ochrospiza, Dendrospiza and Pseudochloroptila (Cape siskins) as distinct genera. Alario is sister to Serinus canicollis whereas the others are intermingled in a clade comprised primarily by Crithagra spp. The use of Serinus is confined to the Palaearctic canaries and allied species, and Crithagra for the strictly Afrotropical clade. Since the cytochrome b sequence divergence between the allopatric Cape (S. [c.] canicollis) and Yellow-crowned (S. [c.] flavivertex) canaries (2.8%) was similar to differences between other closely-related species and there are marked plumage differences between these taxa, we suggest that they be elevated to full species rank.  相似文献   

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Eunicid annelids inhabit diverse marine habitats worldwide, have ecological and economic importance and have been pictured in the news as giant predator worms. They compose a traditional stable taxon recently supported as monophyletic but characterized by plesiomorphies. Most genera within the family have been recovered as paraphyletic in previous studies. We present a phylogenetic hypothesis for eunicid based on molecular (COI, 16S rDNA, 18S rDNA) and morphological data (213 characters), including an explicit attempt to account for serial homology. Eunicidae as well as monophyletic genera Marphysa sensu stricto and Lysidice is redefined based on synapomorphies. Nematonereis is synonymized to Lysidice. Leodice and Nicidion are resurrected to name monophyletic groups including species previously included in Eunice and Marphysa sensu lato. Traditional diagnostic characters such as the absence/presence of peristomial cirri, lateral antennae and branchiae are homoplasies and not informative at the generic level. Different coding of traditional characters (i.e. articulation of prostomial appendages) and novel characters of prostomial features and regionalization of the body support the monophyly of the family and genera level clades. Thus, the phylogenetic hypothesis presented here and the evolution of characters provided background information for taxonomic changes yielding evolutionary meaningful classification and diagnoses for the family and genera.  相似文献   

14.
The large genus Saxifraga, which consists of ≈400 morphologically and cytologically diverse species, has long been considered taxonomically complex. Phylogenetic analysis of over 2500 bp of chloroplast sequence data derived from matK and rbcL was employed to examine relationships among sections of Saxifraga, the segregate genera Zahlbrucknera, Saxifragopsis, and Cascadia, and the relationships of these taxa to other Saxifragaceae sensu stricto. Phylogenetic trees resulting from separate analyses of the matK and rbcL sequences were highly congruent; phylogenetic analysis of a combined matK–rbcL data matrix was therefore also conducted. Our analyses indicate that Saxifraga is polyphyletic, comprising two well-differentiated clades. One clade, Saxifraga sensu stricto, is the sister to the remainder of the family and consists of Saxifraga sections Irregulares, Heterisia, Trachyphyllum, Cymbalaria, Mesogyne, Xanthizoon, Porphyrion, Ciliatae, Cotylea, Ligulatae, Saxifraga, and Gymnopera. With the exception of Gymnopera, the species-rich sections of this clade are monophyletic. Also part of this clade is the problematic Zahlbrucknera paradoxa, which is allied with members of section Saxifraga. A second major clade of Saxifraga species, Micranthes sensu lato, comprises the large section Micranthes, as well as the segregate genus Cascadia, and S. tolmiei of section Merkianae. This clade is allied with the Heuchera, Darmera, and Chrysosplenium-Peltoboykinia groups of genera. The segregate genus Saxifragopsis is only distantly related to species of Saxifraga, and is instead the sister to Astilbe. The monotypic Oresitrophe is confirmed as a member of the Darmera group of genera. These results suggest that the floral features used to define Saxifraga may simply be symplesiomorphic in these well-separated Saxifraga lineages. Furthermore, the enormous cytological diversity encompassed by Saxifraga likely represents two independent instances of extensive aneuploidy and polyploidy in Saxifragaceae.  相似文献   

15.
Evidence for Gondwanan vicariance in an ancient clade of gecko lizards   总被引:2,自引:0,他引:2  
Aim Geckos (Reptilia: Squamata), due to their great age and global distribution, are excellent candidates to test hypotheses of Gondwanan vicariance against post‐Gondwanan dispersal. Our aims are: to generate a phylogeny of the sphaerodactyl geckos and their closest relatives; evaluate previous phylogenetic hypotheses of the sphaerodactyl geckos with regard to the other major gecko lineages; and to use divergence date estimates to inform a biogeographical scenario regarding Gondwanan relationships and assess the roles of vicariance and dispersal in shaping the current distributions of the New World sphaerodactyl geckos and their closest Old World relatives. Location Africa, Asia, Europe, South America, Atlantic Ocean. Methods We used parsimony and partitioned Bayesian methods to analyse data from five nuclear genes to generate a phylogeny for the New World sphaerodactyl geckos and their close Old World relatives. We used dispersal–vicariance analysis to determine ancestral area relationships among clades, and divergence times were estimated from the phylogeny using nonparametric rate smoothing. Results We recovered a monophyletic group containing the New World sphaerodactyl genera, Coleodactylus, Gonatodes, Lepidoblepharis, Pseudogonatodes and Sphaerodactylus, and the Old World Gekkotan genera Aristelliger, Euleptes, Quedenfeldtia, Pristurus, Saurodactylus and Teratoscincus. The dispersal–vicariance analysis indicated that the ancestral area for this clade was North Africa and surrounding regions. The divergence between the New World spaherodactyl geckos and their closest Old World relative was estimated to have occurred c. 96 Myr bp . Main conclusions Here we provide the first molecular genetic phylogenetic hypothesis of the New World sphaerodactyl geckos and their closest Old World relatives. A combination of divergence date estimates and dispersal–vicariance analysis informed a biogeographical scenario indicating that the split between the sphaerodactyl geckos and their African relatives coincided with the Africa/South America split and the opening of the Atlantic Ocean. We resurrect the family name Sphaerodactylidae to represent the expanded sphaerodactyl clade.  相似文献   

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Ranunculaceae are a nearly cosmopolitan plant family with the highest diversity in northern temperate regions and with relatively few representatives in the tropics. As a result of their position among the early diverging eudicots and their horticultural value, the family is of great phylogenetic and taxonomic interest. Despite this, many genera remain poorly sampled in phylogenetic studies and taxonomic problems persist. In this study, we aim to clarify the infrageneric relationships of Clematis by greatly improving taxon sampling and including most of the relevant subgeneric and sectional types in a simultaneous dynamic optimization of phenotypic and molecular data. We also investigate how well the available data support the hypothesis of phylogenetic relationships in the family. At the family level, all five currently accepted subfamilies are resolved as monophyletic. Our analyses strongly imply that Anemone s.l. is a grade with respect to the Anemoclema Clematis clade. This questions the recent sinking of well‐established genera, including Hepatica, Knowltonia and Pulsatilla, into Anemone. In Clematis, 12 clades conceptually matching the proposed sectional division of the genus were found. The taxonomic composition of these clades often disagrees with previous classifications. Phylogenetic relationships between the section‐level clades remain highly unstable and poorly supported and, although some patterns are emerging, none of the proposed subgenera is in evidence. The traditionally recognized and horticulturally significant section Viorna is both nomenclaturally invalid and phylogenetically unsupported. Several other commonly used sections are likewise unjustified. Our results provide a phylogenetic background for a natural section‐level classification of Clematis.  相似文献   

17.
Previous molecular phylogenetic analyses have demonstrated that Saxifragaceae sensu lato are polyphyletic, with component lineages scattered throughout the eudicots. As part of our effort to elucidate the relationships of members of Engler and Prantl's Saxifragaceae s. l., we undertook a molecular systematic study of subfamily Brexioideae, which comprises three genera:Brexia, Ixerba, andRoussea. Not all taxonomic treatments have concurred, however, in placing these genera together. To elucidate relationships among these three genera as well as their relationships to other angiosperms we constructed large data sets ofrbcL, 18S rDNA, andrbcL + 18S rDNA sequences. Our phylogenetic analyses indicate clearly that Brexioideae are polyphyletic.Brexia is part of a celastroid clade that also includesParnassia, Lepuropetalon, and Celastraceae.Ixerba appears as sister to a large eurosid I clade;Roussea appears as part of Asterales. Molecular data, therefore, indicate that Brexioideae are a polyphyletic assemblage and component genera should ultimately be incorporated into other groups. Our studies continue to demonstrate the polyphyly not only Saxifragaceae s. l., but also of its constituent subfamilies.The first author would like to dedicate this paper to Kurt Schuchart, a good friend who passed away during this research.  相似文献   

18.
A comprehensive molecular phylogeny of lowland antpittas in the genera Hylopezus and Myrmothera indicated that Hylopezus, as currently defined, is paraphyletic with respect to Myrmothera and Grallaricula. Specifically, both species now placed in Myrmothera, Hylopezus dives, Hylopezus fulviventris and Hylopezus berlepschi form a strongly supported clade that is sister to a clade comprised by Hylopezus perspicillatus, Hylopezus auricularis, Hylopezus ochroleucus, Hylopezus whittakeri, Hylopezus paraensis, Hylopezus macularius, and Hylopezus dilutus. Furthermore, Hylopezus nattereri is sister to a clade glade grouping Myrmothera, Hylopezus, and Grallaricula, representing the most divergent lineage in this complex. Our approach to assess diagnosability and define generic boundaries among these taxa integrates phylogenetic relationships with morphological and acoustic traits. Given that phenotypic and ecological differences do not warrant merging H. nattereri into any other genus, and because there is no generic name available for H. nattereri, we describe herein a new genus for this Atlantic Forest endemic lineage, Cryptopezus gen. n. We also redefine generic limits in Myrmothera and Hylopezus to have a taxonomic classification concordant with their phylogenetic relationships.  相似文献   

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Five cyanobacterial strains exhibiting Nostoc-like morphology were sampled from the biodiversity hotspots of the northeast region of India and characterized using a polyphasic approach. Molecular and phylogenetic analysis using the 16S rRNA gene indicated that the strains belonged to the genera Amazonocrinis and Dendronalium. In the present investigation, the 16S rRNA gene phylogeny clearly demarcated two separate clades of Amazonocrinis. The strain MEG8-PS clustered along with Amazonocrinis nigriterrae CENA67, which is the type strain of the genus. The other three strains ASM11-PS, RAN-4C-PS, and NP-KLS-5A-PS clustered in a different clade that was phylogenetically distinct from the Amazonocrinis sensu stricto clade. Interestingly, while the 16S rRNA gene phylogeny exhibited two separate clusters, the 16S–23S ITS region analysis did not provide strong support for the phylogenetic observation. Subsequent analyses raised questions regarding the resolving power of the 16S–23S ITS region at the genera level and the associated complexities in cyanobacterial taxonomy. Through this study, we describe a novel genus Ahomia to accommodate the members clustering outside the Amazonocrinis sensu stricto clade. In addition, we describe five novel species, Ahomia kamrupensis, Ahomia purpurea, Ahomia soli, Amazonocrinis meghalayensis, and Dendronalium spirale, in accordance with the International Code of Nomenclature for algae, fungi, and plants (ICN). Apart from further enriching the genera Amazonocrinis and Dendronalium, the current study helps to resolve the taxonomic complexities revolving around the genus Amazonocrinis and aims to attract researchers to the continued exploration of the tropical and subtropical cyanobacteria for interesting taxa and lineages.  相似文献   

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