首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Ichneumonoid phylogeny is revised on the basis of morphological, palaeontological and molecular evidence. The only previous formal cladistic study of the phylogeny of the families of the superfamily Ichneumonoidea made many assumptions about what families lower taxa belonged to and was based on a very limited set of characters, nearly all of which were uninformative at family level. We have subdivided both Ichneumonidae and Braconidae into major groups, investigated several new character systems, reinterpreted some characters, scored several character states for extinct taxa by examining impression fossils using environment chamber scanning electron microscopy, and included data for a significant new subfamily of Braconidae from Cretaceous amber of New Jersey. Sixteen different variants of the data set were each subjected to parsimony analysis without weighting and with successive approximations weighting employing both maximum and minimum values of both the retention and rescaled consistency indices. Each analysis resulted in one of seven different strict consensus trees. Consensus trees based on subsets of these trees, selected on the basis of the optimal character compatibility index (OCCI), resulted in an eighth distinct tree. All trees had the Braconidae monophyletic with the Trachypetinae as the basal clade, and also had a clade comprising various arrangements of Apozyginae, the Rhyssalinae group, Aphidiinae and 'other cyclostomes', but relationships among the remaining braconid groups varied between trees. Only one of the consensus trees had the Ichneumonidae (including Tanychorella ) monophyletic. The Eoichneumonidae + Tanychora are the sister group the Braconidae in two of the consensus trees. Paxylommatinae were basal in the clade comprising the Eoichneumonidae + Tanychora and the Braconidae. The preferred tree, based on the highest OCCI was used for interpreting character state transitions.  相似文献   

2.
Entomopathogenic nematodes of the genus Steinernema are lethal parasites of insects that are used as biological control agents of several lepidopteran, dipteran and coleopteran pests. Phylogenetic relationships among 25 Steinernema species were estimated using nucleotide sequences from three genes and 22 morphological characters. Parsimony analysis of 28S (LSU) sequences yielded a well-resolved phylogenetic hypothesis with reliable bootstrap support for 13 clades. Parsimony analysis of mitochondrial DNA sequences (12S rDNA and cox 1 genes) yielded phylogenetic trees with a lower consistency index than for LSU sequences, and with fewer reliably supported clades. Combined phylogenetic analysis of the 3-gene dataset by parsimony and Bayesian methods yielded well-resolved and highly similar trees. Bayesian posterior probabilities were high for most clades; bootstrap (parsimony) support was reliable for approximately half of the internal nodes. Parsimony analysis of the morphological dataset yielded a poorly resolved tree, whereas total evidence analysis (molecular plus morphological data) yielded a phylogenetic hypothesis consistent with, but less resolved than trees inferred from combined molecular data. Parsimony mapping of morphological characters on the 3-gene trees showed that most structural features of steinernematids are highly homoplastic. The distribution of nematode foraging strategies on these trees predicts that S. hermaphroditum, S. diaprepesi and S. longicaudum (US isolate) have cruise forager behaviours.  相似文献   

3.
The genusLecanactis, with 24 species, has been phylogenetically analysed using cladistic parsimony methods and support tests. Morphological, anatomical and chemical data were used, comprising 38 characters. Twelve equally most parsimonious trees were obtained. The successive approximations character weighting method gave one most parsimonious tree. The ingroup,Lecanactis, is supported as monophyletic. Although parsimony jackknifing and Bremer support indicate that the trees are poorly supported, some groups are wholly or partly distinguished in both the strict consensus tree, the successive weighting tree and the Jac tree.  相似文献   

4.
The Lejeuneaceae are the largest family of the liverworts (Hepaticae), with almost a thousand species in 91 currently accepted genera. We analysed phylogenetic relationships of 69 genera, representing all major subfamilies and tribes recognized in the family, by using 49 informative morphological characters (31 gametophytic, 18 sporophytic), one chemical character, and applying equal and successive weighting of characters and parsimony analysis. In all trees recovered, the Lejeuneaceae were monophyletic with Nipponolejeunea (subfam. Nipponolejeuneoideae) forming the basalmost lineage. The remaining genera clustered in two major groups, the monophyletic Lejeuneoideae (52 genera) and the paraphyletic Ptychanthoideae (16 genera). Within each, several multigeneric lineages corresponding in part to previously described taxa were recovered: the Acrolejeuneinae and Ptychanthinae clades in the Ptychanthoideae, and the Brachiolejeuneinae, Lejeuneeae and Tuyamaella–Cololejeunea clades in the Lejeuneoideae. Bryopteris , a genus sometimes treated as a separate family, was nested in the Ptychanthinae clade. The Tuyamaella–Cololejeunea lineage corresponded with three previously recognized subfamilies (Cololejeuneoideae, Myriocoleoideae and Tuyamaelloideae) and contained genera with neotenic features, in two subclades. These features seemed to have originated by multiple heterochronic events: single origins were detected for 'protonemal neoteny' and 'primary neoteny', whereas 'secondary neoteny' probably evolved twice. Relationships within the large Lejeuneeae clade (43 genera) remained largely unresolved, although several putative lineages were detected in majority rule trees. Additional characters such as DNA sequences may provide better phylogenetic resolution in this group.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 391–410.  相似文献   

5.
The intrasubfamilial classification of Microdontinae Rondani (Diptera: Syrphidae) has been a challenge: until recently more than 300 out of more than 400 valid species names were classified in Microdon Meigen. We present phylogenetic analyses of molecular and morphological characters (both separate and combined) of Microdontinae. The morphological dataset contains 174 characters, scored for 189 taxa (9 outgroup), representing all 43 presently recognized genera and several subgenera and species groups. The molecular dataset, representing 90 ingroup species of 28 genera, comprises sequences of five partitions in total from the mitochondrial gene COI and the nuclear ribosomal genes 18S and 28S. We test the sister‐group relationship of Spheginobaccha with the other Microdontinae, attempt to elucidate phylogenetic relationships within the Microdontinae and discuss uncertainties in the classification of Microdontinae. Trees based on molecular characters alone are poorly resolved, but combined data are better resolved. Support for many deeper nodes is low, and placement of such nodes differs between parsimony and Bayesian analyses. However, Spheginobaccha is recovered as highly supported sister group in both. Both analyses agree on the early branching of Mixogaster, Schizoceratomyia, Afromicrodon and Paramicrodon. The taxonomical rank in relation to the other Syrphidae is discussed briefly. An additional analysis based on morphological characters only, including all 189 taxa, used implied weighting. A range of weighting strengths (k‐values) is applied, chosen such that values of character fit of the resulting trees are divided into regular intervals. Results of this analysis are used for discussing the phylogenetic relationships of genera unrepresented in the molecular dataset.  相似文献   

6.
Brachytheciaceae is often considered a taxonomically difficult group of mosses. For example, morphological variation has led to difficulty in generic delimitation. We used DNA sequence data (chloroplast psbT‐H and trnL‐F and nuclear ITS2) together with morphology (63 characters) to examine the relationships within this family. The combined unaligned length of the DNA sequences used in the phylogenetic analyses varied between 1277 and 1343 bp. For phylogeny reconstruction we performed direct optimization, as implemented in POY. Analyses were performed with three different gap costs and the morphological data partition was weighted both: (1) equal to gap cost, and (2) with a weight of one. The utility of sensitivity analysis has recently been cast into doubt; hence in this study it was performed only to explore the effects of weighting on homology statements and topologies and to enable more detailed comparisons between earlier studies utilizing the direct optimization method. The wide sequence length variation of non‐coding ITS2 sequences resulted in character optimizations (i.e., “alignments”) of very different lengths when various gap costs were applied. Despite this variation, the topologies of equally parsimonious trees remained fairly stable. The inclusion of several outgroups, instead of only one, was observed to increase the congruence between data sets and to slightly increase the resolution. An inversion event in the 9 bp loop region in the chloroplast psbT‐N spacer in mosses has been postulated to include only uninformative variation, thus possibly negatively impacting the phylogeny reconstruction. Despite this inversion, its variation within Brachytheciaceae was clearly congruent with information from other sources, but inclusion of these 9 bp in the analysis had only a minor effect on the phylogenetic results. In the most parsimonious topology, which was obtained with equal weighting of all data, Meteoriaceae and Brachytheciaceae were resolved as monophyletic sister groups, which had recently been suggested based on a few shared morphological characters. Our study revealed some new generic relationships within the Brachytheciaceae, which are discussed in light of the morphological characters traditionally used for generic delimitation.  相似文献   

7.
The most extensive combined phylogenetic analyses of the subclass Marchantiidae yet undertaken was conducted on the basis of morphological and molecular data. The morphological data comprised 126 characters and 56 species. Taxonomic sampling included 35 ingroup species with all genera and orders of Marchantiidae sampled, and 21 outgroup species with two genera of Blasiidae (Marchantiopsida), 15 species of Jungermanniopsida (the three subclasses represented) and the three genera of Haplomitriopsida. Takakia ceratophylla (Bryophyta) was employed to root the trees. Character sampling involved 92 gametophytic and 34 sporophytic traits, supplemented with ten continuous characters. Molecular data included 11 molecular markers: one nuclear ribosomal (26S), three mitochondrial genes (nad1, nad5, rps3) and seven chloroplast regions (atpB, psbT‐psbH, rbcL, ITS, rpoC1, rps4, psbA). Searches were performed under extended implied weighting, weighting the character blocks against the average homoplasy. Clade stability was assessed across three additional weighting schemes (implied weighting corrected for missing entries, standard implied weighting and equal weighting) in three datasets (molecular, morphological and combined). The contribution from different biological phases regarding node recovery and diagnosis was evaluated. Our results agree with many of the previous studies but cast doubt on some relationships, mainly at the family and interfamily level. The combined analyses underlined the fact that, by combining data, taxonomic enhancements could be achieved regarding taxon delimitation and quality of diagnosis. Support values for many clades of previous molecular studies were improved by the addition of morphological data. The long‐held assumption that morphology may render spurious or low‐quality results in this taxonomic group is challenged. The morphological trends previously proposed are re‐evaluated in light of the new phylogenetic scheme.  相似文献   

8.
It has been shown that increased character sampling betters the accuracy of phylogenetic reconstructions in the case of molecular data. A recently published analysis of avian higher-level phylogenetics based on 2954 morphological characters now provides an empirical example to test whether this is also true in the case of morphological characters. Several clades are discussed which are supported by multiple analyses of mutually independent molecular data (sequences of nuclear genes on different chromosomes and mitochondrial genes) as well as morphological apomorphies, but did not result from parsimony analysis of the large morphological data set. Incorrect character scorings in that analysis notwithstanding, it is concluded that in the case of morphological data, increased character sampling does not necessarily better the accuracy of a phylogenetic reconstruction. Because morphological characters usually have a strongly varying complexity, many simple and homoplastic characters may overrule fewer ones of greater phylogenetic significance in large data sets, thus producing a low ratio of phylogenetic signal to 'noise' in the data.  相似文献   

9.
A phylogenetic analysis of the leafhopper genus Apogonalia was conducted based on a matrix of 40 terminal taxa and 147 morphological characters. The analysis yielded 1391 equally most‐parsimonious trees, which do not support the monophyly of Apogonalia in the strict consensus. A successive weighting procedure yielded 62 trees in which the genus appeared as a monophyletic group. The strict consensus of these 62 trees is almost entirely dichotomous, showing only two polytomies. The test of phylogenetic integrity was applied for distinct variations of three species: A. germana, A. sanguinipes, and A. histrio. Only for the first species was the conjecture that its variations belong to the same entity corroborated. The best‐supported clade within Apogonalia, which has several synapomorphies and high branch support indices, comprises nine Antillean endemic species. This distributional pattern probably was originated by vicariance in the Late Cretaceous, when the Proto‐Antillean archipelago was pushed north‐eastward by the Caribbean Plate to become the modern Greater Antilles. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163 , 548–570.  相似文献   

10.
The positioning of the Pentastomida among the Metazoa has provoked many debates up to the present. On the other hand, the internal relationships among the pentastomid subgroups have received much less attention in the past. We provide the first phylogenetic analyses under Hennigian principles. Thirty-two morphological characters were selected from the primary literature, analyzed manually, and then with the program Hennig86. Four most parsimonious trees were obtained; these were analyzed by successive weighting and reduced to 1 consensus cladogram 380 steps long, with a consistency index of 0.98 and a retention index of 0.99. Characters were also analyzed as unordered, producing results that were congruent with the previous analyses. The internal groups were ordered according to the following system: (Heymnonsicambria + Haffnericambria + Backlericambria (Cephalobaenida (Railietiellida nov. (Reighardiida nov. (Porocephalida (Linguatuloidea (Linguatulidae + Subtriquetridae) + Porocephaloidea (Sebekidae + Porocephalidae))))))). This phylogenetic system is largely congruent with the first modern taxonomic arrangement proposed for the Pentastomida.  相似文献   

11.
The phylogenetic relationships of spionid genera are estimated from parsimony analyses of morphological characters, with Trochochaetidae, Poecilochaetidae and Uncispionidae as outgroups. A first analysis of currendy recognised genera proved inconclusive and even exclusion of six of the most polymorphic genera resulted in 13 305 equally parsimonious trees and a fully collapsed consensus tree. A second analysis using only the type species of each genus, yielded four equally parsimonious trees; reduced to two after successive weighting. The topologies of these two trees indicated division of the family into four main groups: (1) Aonidella and Xandaros; (2) Prionospio (sensu fato)-complex, Laonice, Spiophanes and Aonides; (3) a large assemblage of genera, including Polydora-{senm late), Scolelepis, Malacoceros and Spio; (4) Atherospio, Pseudatherospio and Pygospiopsis. Earlier literature classifications of the group are evaluated and compared with die new results.  相似文献   

12.
An adequate stratigraphic record can not only aid in both cladistic and stratophenetic reconstruction of phytogenies, but can also serve in estimating the temporal consistency of the resulting phylogenetic trees. For hypothetical data sets, cladistically constructed trees can be as consistent with the temporal distribution of sampled populations or species as those constructed stratophenetically. Empirical testing in taxonomic groups with sufficiently dense fossil records is needed to show whether, and under what conditions, this potential can be realized. A stratophenetic tree and cladistic trees based on several approaches to character weighting were constructed for Caribbean Neogene species of the bryozoan Metrarabdotos with multiple‐character data from closely spaced sequential populations. The modular morphology and highly punctuated evolutionary pattern of these species blur the distinction between continuous and discrete characters, so that all available characters are potentially of equal significance in establishing phytogenies, rather than just those with discrete states conventionally used in cladistic analysis. However, only the cladistic trees generated with all characters weighted to emphasize contribution to species discrimination have temporal consistencies that are clearly significant statistically and approach that of the stratophenetic tree in magnitude. These results provide a start toward establishing general guidelines for cladistic analysis of taxa with stratigraphie records too sparse for stratophenetic reconstruction.  相似文献   

13.
Abstract— Protein variation among 37 species of carcharhiniform sharks was examined at 17 presumed loci. Evolutionary trees were inferred from these data using both cladistic character and a distance Wagner analysis. Initial cladistic character analysis resulted in more than 30 000 equally parsimonious tree arrangements. Randomization tests designed to evaluate the phylogenetic information content of the data suggest the data are highly significantly different from random in spite of the large number of parsimonious trees produced. Different starting seed trees were found to influence the kind of tree topologies discovered by the heuristic branch swapping algorithm used. The trees generated during the early phases of branch swapping on a single seed tree were found to be topologically similar to those generated throughout the course of branch swapping. Successive weighting increased the frequency and the consistency with which certain clades were found during the course of branch swapping, causing the semi-strict consensus to be more resolved. Successive weighting also appeared resilient to the bias associated with the choice of initial seed tree causing analyses seeded with different trees to converge on identical final character weights and the same semi-strict consensus tree.
The summary cladistic character analysis and the distance Wagner analysis both support the monophyly of two major clades, the genus Rhizoprionodon and the genus Sphyrna. . The distance Wagner analysis also supports the monophyly of the genus Carcharhinus . However, the cladistic analysis suggests that Carcharhinus is a paraphyletic group that includes the blue shark Prionace glauca .  相似文献   

14.
15.
Aphids of the tribe Eriosomatini are typically associated with the tree genera Ulmus and Zelkova as the primary host, on which they induce several types of leaf gall. To elucidate evolutionary changes in the aphid–host associations and gall morphology, phylogenetic relationships were inferred using 36 species (28 in the ingroup) and based on 52 morphological characters. Phylogenetic analysis with equal character weighting led to hundreds of most‐parsimonious trees, and the strict consensus of these was poorly resolved. However, the successive weighting of characters yielded three most‐parsimonious trees. The strict consensus of these supported the monophyly of the Eriosomatini and the monophyly of most genera. Reconstruction of the aphid–host associations on the consensus tree indicated that the ancestral Eriosomatini were associated with Zelkova and that the association with Ulmus evolved twice independently. Ancestral reconstruction suggests that galls of the leaf‐roll type are ancestral to those of the completely and incompletely closed pouch type, and that each type of pouch galls evolved independently. It is suggested that despite early diversification of the Eriosomatini on Zelkova species, Zelkova‐associated eriosomatines had become extinct or survived as relict parthenogens on the secondary host due to the elimination of Zelkova in most regions since the late Tertiary. In contrast, two large genera in the Eriosomatini, Eriosoma and Tetraneura, are associated with the largest elm section Ulmus whose elements are distributed widely in Eurasia, including boreal regions. Therefore, the available evidence suggests that the present species diversity and distribution patterns of the eriosomatines have been largely affected by the diversification and extinction of their host plants during the late Tertiary and Quaternary.  相似文献   

16.
A cladistic analysis of Orchidaceae was undertaken for 98 genera using 71 morphological apomorphies based on a reconsideration of previous character analyses and newly discovered variation. The equally weighted analysis found 60 000 most parsimonious trees with low consistency (CI = 0.29) but high retention (RI = 0.83). The strict consensus reveals a significant amount of structure, and most traditionally recognized subfamilies are supported as monophyletic, including the Apostasioideae, Cypripedioideae, Spiranthoideae, and Epidendroideae. Orchidoideae in the broad sense are paraphyletic, giving rise to spiranthoids. Vanilloids are sister to epidendroids, although exhibiting several states otherwise found only in clearly basal groups, such as Apostasioideae. The nonvandoid epidendroids are poorly resolved, due to a high degree of homoplasy. The vandoids appear to be monophyletic, contrary to recent molecular evidence, possibly due to repeated parallel development of the vandoid character suite. The importance of vegetative characters as evidence putatively independent from floral features is demonstrated in the placement of Tropidia. Implied weighting analysis of these data resulted in similar patterns at high levels, although the Orchidoideae and Spiranthoideae may each be monophyletic and the nonvandoid epidendroids are more resolved. The high degree of structure implied in previous orchid classifications must be reconsidered, given the poor resolution at lower levels in the present trees.  相似文献   

17.
Abstract— A cladistic analysis of the "green ash" eucalypts, informal subgenus " Monocalyptus ", is presented- As a first step, ordination methods of principal coordinates analysis and multidimensional scaling delineated some terminal taxa. The cladistic analysis, applying parsimony methods to the unweighted data set, yielded 25 equally parsimonious trees, each with a consistency index of 0.57.
Farris' successive approximations approach to character weighting produced one tree with a consistency index of 0.74.
An informal classification of the group, superseries Eucalyptus , is based on that cladogram. The biogeographic history of superseries Eucalyptus is interpreted from the cladogram as having been caused by lour vicariant events in southeastern Australia, in combination with a suite of ecological features that overlie the biogeographic area-pattern.  相似文献   

18.
The evolutionary relationships among most (143 genera) of the currently recognized genera of the braconid wasp subfamily Doryctinae were investigated using maximum parsimony analysis, employing 100 characters from external morphology and four additional, less well‐studied character systems (male genitalia, ovipositor structure, venom apparatus and larval cephalic structure). We investigated the ‘performance’ of characters from external morphology and the other character systems and the effects of abundant missing entries by comparing the data decisiveness, retention and consistency indices of four different character partitions. The results indicate that the performances of the different partitions are not related to the proportions of missing entries, but instead are negatively correlated to their proportion of informative characters, suggesting that the morphological information in this group is subject to high levels of homoplasy. The external morphological partition is significantly incongruent with respect to a data set comprising the other character systems based on the ILD test. Analyses supported neither the monophyly of the large tribes Doryctini and Hecabolini, nor the monophyly of the Spathiini and Heterospilini. Relationships obtained from successive approximation weighting analysis for the complete data differ considerably from the currently accepted tribal and subtribal classifications. The only exceptions were the Ypsistocerini and the Ecphylini, whose recognized members were recovered in single clades. A close relationship between the Binaerini and Holcobraconini, and also Monarea, is consistently supported by venom apparatus and ovipositor structure characters but is not indicated by external morphological data. Low bootstrap values obtained for most of the recovered clades in all analyses do not allow us to propose a meaningful reclassification for the group at this time. A complete list of the recognized genera and their synonymies is given. © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society, 2004, 142 , 369–404.  相似文献   

19.
The phylogenetic relationships among the loliginid squids, a species-rich group of shallowwater muscular squids, have been investigated recently using several approaches, including allozyme electrophoresis and analyses of morphological and DNA sequence data, yet no consensus has been reached. This study examines the effects of combining multiple data sets (morphology, allozymes and DNA sequence data from two mitochondrial genes) on estimates of loliginid phylogeny. Various data combinations were analysed under three maximum parsimony weighting schemes: equal weights for all characters, successive approximations and implicit weights parsimony. When feasible, support for branches within trees was assessed with nonparametric bootstrapping and decay analysis. Some ingroup relationships were consistent across all analyses, but relationships among outgroup taxa and basal ingroup taxa varied. Combining data increased bootstrap support for several nodes. Methods that downweight highly variable characters (i.e. successive approximations and implicit weights parsimony) produced very similar trees which included two major clades: a clade consisting of all species sampled from American waters (except Sepioteuthis ), and a clade of several east Atlantic species ( Loligo forbesi Steenstrup, Loligo vulgaris Lamarck and Loligo reynaudi d'Orbigny) plus several Indo-West Pacific species in the genera Uroteuthis and Loliolus. The Sepioteuthis species occupied a basal position within Loliginidae, but Sepioteuthis itself was not always monophyletic. The position of a clade of a few Lolliguncula species and Loligo (Alloteuthis) also varied across analyses. A new loliginid classification is proposed based on these findings.  相似文献   

20.
A cladistic analysis of the order Marchantiales based on morphological characters (43 characters) did not agree with the classification in current use. Molecular sequences of nuclear-encoded 26S rRNA genes of seven species of the order and two out-groups (1254–1299 bp) were analysed to solve this contradiction. Results between morphologial and sequence data are conflicting. The combination of the two data sets shows that a weighting of the morphological data corresponding to equal contributions of the two sets resolves contradiction. We demonstrate that the structure of two data sets can be compatible even if the resultant trees are incongruent. Addition of a few compatible data (for instance, via character weighting) can result in congruent trees. The taxonomic incongruence we observed could illustrate a case of too limited molecular sampling.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号