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1.
Phylogenetic analysis of higher-level relationships of Odonata   总被引:3,自引:1,他引:2  
Abstract. This is the most comprehensive analysis of higher‐level relationships in Odonata conducted thus far. The analysis was based on a detailed study of the skeletal morphology and wing venation of adults, complemented with a few larval characters, resulting in 122 phylogenetically informative characters. Eighty‐five genera from forty‐five currently recognized families and subfamilies were examined. In most cases, several species were chosen to serve as exemplars for a given genus. The seven fossil outgroup taxa included were exemplar genera from five successively more distant odonatoid orders and suborders: Tarsophlebiidae (the closest sister group of Odonata, previously placed as a family within ‘Anisozygoptera’), Archizygoptera, Protanisoptera, Protodonata and Geroptera. Parsimony analysis of the data, in which characters were treated both under equal weights and implied weighting, produced cladograms that were highly congruent, and in spite of considerable homoplasy in the odonate data, many groupings in the most parsimonious cladograms were well supported in all analyses, as indicated by Bremer support. The analyses supported the monophyly of both Anisoptera and Zygoptera, contrary to the well known hypothesis of zygopteran paraphyly. Within Zygoptera, two large sister clades were indicated, one comprised of the classical (Selysian) Calopterygoidea, except that Amphipterygidae, which have traditionally been placed as a calopterygoid family, nested within the other large zygopteran clade comprised of Fraser's ‘Lestinoidea’ plus ‘Coenagrionoidea’ (both of which were shown to be paraphyletic as currently defined). Philoganga alone appeared as the sister group to the rest of the Zygoptera in unweighted cladograms, whereas Philoganga + Diphlebia comprised the sister group to the remaining Zygoptera in all weighted cladograms. ‘Anisozygoptera’ was confirmed as a paraphyletic assemblage that forms a ‘grade’ towards the true Anisoptera, with Epiophlebia as the most basal taxon. Within Anisoptera, Petaluridae appeared as the sister group to other dragonflies.  相似文献   

2.
Squamate phylogeny and the relationships of snakes and mosasauroids   总被引:1,自引:0,他引:1  
Cladistic analysis of extant and fossil squamates (95 characters, 26 taxa) finds the fossil squamate, Coniasaurus Owen, 1850, to be the sister-group of the Mosasauroidea (mosasaurs and aigialosaurs). This clade is supported in all 18 shortest cladograms (464 steps; CI 0.677; HI 0.772) by nine characters of the dermatocranium, maxilla, and mandible. A Strict Consensus Tree of the 18 shortest trees collapses to a basal polytomy for most major squamate clades including the clade (Coniasaurus, Mosasauroidea). A Majority Rule Consensus Tree shows that, in 12 of 18 shortest cladograms, the clade Coniasaurus- Mosasauroidea is the sister-group to snakes (Scolecophidia (Alethinophidia, Dinilysia); this entire clade, referred to as the Pythonomorpha ([[Scolecophidia [Alethinophidia, Dinilysia]], [Coniasaurus, Mosasauroidea]]) is the sister-group to all other scleroglossans. Pythonomorpha is supported in these 12 cladograms by nine characters related to the lower jaw and cranial kinesis. In 6 of 18 shortest cladograms, snakes are the sister-group to the clade (Amphisbaenia (Dibamidae (Gekkonoidea, Eublepharidae))). None of the cladograms support the hypothesis that coniasaurs and mosasauroids are derived varanoid anguimorphs. Two additional analyses were conducted: (1) manipulation and movement of problematic squamate clades while constraining ‘accepted’ relationships; (2) additional cladistic analyses beginning with extant taxa, and sequentially adding fossil taxa. From Test I, at 467 steps, Pythonomorpha can be the sister-group to the Anguimorpha, Scincomorpha, ‘scinco-gekkonomorpha’ [scincomorphs, gekkotans, and amphibaenids-dibamids]. At 471 steps Pythonomorpha can be placed within Varanoidea. Treating only mosasauroids and coniasaurs as a monophyletic group: 469 steps, mosasauroids and coniasaurs as sister-group to Anguimorpha; 479 steps, mosasauroids and coniasaurs nested within Varanoidea. Test II finds snakes to nest within Anguimorpha in a data set of only Mosasauroidea + Extant Squamates; the sistergroup to snakes + anugimorphs is (Amphisbaenia (Dibarnidae (Gekkonoidea, Eublepharidae))). No one particular taxon is identified as a keystone taxon in this analysis, though it appears truc that fossil taxa significantly alter the structure of squamate phylogenetic trees.  相似文献   

3.
 This paper deals with the use of cladistic methods and cladograms in phylogeny reconstruction in plant groups containing numerous taxa. How accurate are the cladograms as to details? Accuracy tests at the level of details require an independently known phylogeny, which excludes most plant groups, but such tests can be carried out in domesticated and experimental plant groups which have documented pedigrees. Four such tests are known and are presented here: a new case in Gilia and three previously published cases in Avena, Hordeum, and Helianthus. The four cases include domesticated and experimental plants, use of morphological and molecular evidence, and presence of dichotomous as well as reticulate phylogenies. The cladograms of the four plant groups all differ in significant details from the known pedigrees. These results are discussed in relation to problems of interpretation of cladograms. Received March 21, 2000 Accepted August 16, 2001  相似文献   

4.
The phylogeny of Phytosciara Frey, Prosciara Frey, Dolichosciara Tuomikoski (together forming Phytosciara sensu Tuomikoski), Lobosciara Steffan and Bradysia Winnertz was studied by parsimony analysis using the computer programs Pee‐Wee and NONA. The analysis was based on sixty‐four morphological characters from adult males, coded for thirty‐nine ingroup and two outgroup terminals. Three cladograms of the maximum fit (Pee‐Wee) and one of the minimum length (NONA) were obtained, some of them with polytomies. Many characters showed much homoplasy in the cladograms. The solution by the fittest cladograms was chosen as the main hypothesis of the phylogeny. Of the groups studied, only Lobosciara appeared monophyletic. The relationships of the taxa in their now revised monophyletic sense are: Dolichosciara + (Lobosciara + ((‘Prosciara’ fuscina group + ‘P’. vulcanata) + (‘P’. mima group + ((‘P’. perfida + (Bradysia + Phytosciara)) + Prosciara)))). Phytosciara Frey, Prosciara, Dolichosciara and Lobosciara in their revised concepts are regarded as genera.  相似文献   

5.
ON CONSENSUS, COLLAPSIBILITY, AND CLADE CONCORDANCE   总被引:1,自引:0,他引:1  
Abstract — Consensus in cladistics is reviewed. Consensus trees, which summarize the agreement in grouping among a set of cladograms, are distinguished from compromise trees, which may contain groups that do not appear in all the cladograms being compared. Only a strict or Nelson tree is an actual consensus. This distinction has implications for the concept of support for cladograms: only those branches supported under all possible optimizations are unambiguously supported. We refer to such cladograms as strictly supported, in contrast to the semistrictly (ambiguously) supported cladograms output by various current microcomputer programs for cladistic analysis. Such semistrictly supported cladograms may be collapsed, however, by a variety of options in various programs. Consideration of collapsibility and optimization on multifurcations leads to some conclusions on the use of consensus. Consensus tree length provides information about character conflict that occurs between, not within, cladograms. We propose the clade concordance index, which employs the consensus tree length to measure inter-cladogram character conflict for all characters among a set of cladograms.  相似文献   

6.
The genus Rheumatobates comprises thirty‐seven species and subspecies of New World water striders belonging to subfamily Rhagadotarsinae. Among species, males vary dramatically in the degree and nature of modifications of the antennae, three pairs of legs and abdominal and genital segments. Characters describing this modification have traditionally been used to differentiate and group species. The general assumption has been that modified species belong to one group and unmodified species to another. These two ‘species groups’ are subdivided into ‘subgroups’, but little effort has been made to resolve relationships among them. We conduct the first numerical cladistic analysis of Rheumatobates using a data set comprised of 102 characters, primarily describing modification of male external morphology. To address concerns about the inclusion of characters to be optimized on the phylogeny, characters describing modification of antennae and hind legs were included and then excluded in separate analyses. A preferred phylogeny was chosen from the four equally parsimonious cladograms found after successive reweighting of characters. There was good resolution at all levels of the phylogeny. Most of the major clades and terminal relationships were moderately to strongly supported, whereas the basal relationships were less well supported. The general assumption that unmodified and modified species form two monophyletic groups was not supported. However, traditionally recognized ‘subgroups’ within the modified species group were largely upheld. The analysis also suggested several major clades and relationships among these clades that were not previously recognized. The exclusion of characters describing modification of antennae and hind legs did not change the resolved major clades of the reconstructed phylogeny.  相似文献   

7.
Edgecombe, G.D. 2010. Palaeomorphology: fossils and the inference of cladistic relationships. —Acta Zoologica (Stockholm) 91 : 72–80 Twenty years have passed since it was empirically demonstrated that inclusion of extinct taxa could overturn a phylogenetic hypothesis formulated upon extant taxa alone, challenging Colin Patterson’s bold conjecture that this phenomenon ‘may be non‐existent’. Suppositions and misconceptions about missing data, often couched in terms of ‘wildcard taxa’ and ‘the missing data problem’, continue to cloud the literature on the topic of fossils and phylogenetics. Comparisons of real data sets show that no a priori (or indeed a posteriori) decisions can be made about amounts of missing data and most properties of cladograms, and both simulated and real data sets demonstrate that even highly incomplete taxa can impact on relationships. The exclusion of fossils from phylogenetic analyses is neither theoretically nor empirically defensible.  相似文献   

8.
PACT: an efficient and powerful algorithm for generating area cladograms   总被引:2,自引:1,他引:1  
Aim To introduce and describe the functioning of a new algorithm, phylogenetic analysis for comparing trees (PACT), for generating area cladograms that provide accurate representation of information contained in taxon–area cladograms. Methods PACT operates in the following steps. Convert all phylogenies to taxon–area cladograms. Convert all taxon–area cladograms to Venn diagrams. Choose any taxon–area cladogram from the set of taxon–area cladograms to be analysed and determine its elements. This will be the template area cladogram. Select a second taxon–area cladogram. Determine its elements. Document which elements in the second tree occur in the template tree (denoted by ‘Y’) and which do not (denoted by ‘N’). Each ‘Y’ indicates a match with previous pattern and these are combined. Each ‘N’ is a new element and is attached to the template area cladogram at the node where it is linked with a Y. This requires two rules: (1) ‘Y + Y = Y’ (combine common elements) as long as they are connected at the same node; and (2) ‘Y + N = YN’ (add novel elements to the template area cladogram at the node where they first appear). Once the novel elements in the second taxon–area cladogram have been added to the template area cladogram, see if any of them can be further combined. This requires three additional rules: (1) ‘Y(Y? = Y(Y?’ (do not combine Y's if they are attached at different nodes on the template area cladogram); (2) ‘Y + YN = YN’ (Y is part of group YN); and (3) ‘YN + YN = YNN’ (Y is the same for each, but each N is different). Repeat for all available taxon–area cladograms. Results Three exemplars demonstrate that PACT provides the most accurate area cladograms for vicariance‐driven biotic diversification, dispersal‐driven biotic diversification and taxon pulse‐driven biotic diversification. PACT can also be used as an a priori method of biogeographical analysis. Main conclusions PACT embodies all the strong points and none of the weaknesses of previously proposed methods of historical biogeography. It is most useful as an a posteriori method, but it is also superior to all previous a priori methods because it does not specify costs, or weights or probabilities, or likelihoods of particular biogeographical processes a priori and is thus sensitive to clade‐specific historical contingencies.  相似文献   

9.
A parsimony‐based phylogenetic analysis of eighty‐three morphological characters of adults and immatures of seventy representatives of the tribes and subfamilies of Membracidae and two outgroup taxa was conducted to evaluate the status and relationships of these taxa. Centrotinae apparently gave rise to Nessorhinini and Oxyrhachini (both formerly treated as subfamilies, now syn.n. and syn.reinst., respectively, of Centrotinae). In contrast to previous analyses, a clade comprising Nicomiinae, Centronodinae, Centrodontinae, and the unplaced genera Holdgatiella Evans, Euwalkeria Goding and Antillotolania Ramos was recovered, but relationships within this clade were not well resolved. Nodonica bispinigera, gen.n. and sp.n., is described and placed in Centrodontini based on its sister‐group relationship to a clade comprising previously described genera of this tribe. Membracinae and Heteronotinae were consistently monophyletic. Neither Darninae nor Smiliinae, as previously defined, was monophyletic on the maximally parsimonious cladograms, but constraining both as monophyletic groups required only one additional step. The monophyly of Stegaspidinae, including Deiroderes Ramos (unplaced in Membracidae), was supported on some but not all equally parsimonious cladograms. More detailed analyses of individual subfamilies, as well as morphological data on the undescribed immatures of several membracid tribes and genera, will be needed to elucidate relationships among tribes and genera. A key to the subfamilies and tribes is provided.  相似文献   

10.
Using a set of cranial morphometric characters, trends of variation in multivariate fluctuating asymmetry were evaluated and compared in populations of African fruit bats Rousettus egyptiacus and Eidolon helvum from the Gulf of Guinea islands, and the adjacent mainland. Levels of asymmetry were compared across populations and species, and significant differences were found in both comparisons. Differences coincided with species‐specific patterns of morphological and genetic differentiation. Concordance of correlation matrices of asymmetry was also compared. Results were significant; concordance is hypothesized to be a by‐product of developmental processes that produce the ‘fox‐like’ morphology shared by these species. Consistency of asymmetry patterns suggests that the developmental pathway producing it is highly canalized. A prediction of the above hypothesis is that a radical change in the ‘fox‐like’ structural pattern would result in breakage of the asymmetry parameter associated with it.  相似文献   

11.
Amino acid sequence data are available for ribulose biphosphate carboxylase, plastocyanin, cytochrome c, and ferredoxin for a number of angiosperm families. Cladistic analysis of the data, including evaluation of all equally or almost equally parsimonious cladograms, shows that much homoplasy (parallelisms and reversals) is present and that few or no well supported monophyletic groups of families can be demonstrated. In one analysis of nine angiosperm families and 40 variable amino acid positions from three proteins, the most parsimonious cladograms were 151 steps long and contained 63 parallelisms and reversals (consistency index = 0.583). In another analysis of six families and 53 variable amino acid positions from four proteins, the most parsimonious cladogram was 161 steps long and contained 50 parallelisms and reversals (consistency index = 0.689). Single changes in both data matrices could yield most parsimonious cladograms with quite different topologies and without common monophyletic groups. Presently, amino acid sequence data are not comprehensive enough for phylogenetic reconstruction among angiosperms. More informative positions are needed, either from sequencing longer parts of the proteins or from sequencing more proteins from the same taxa.  相似文献   

12.
We investigated evolutionary relationships among orders in phylum Rotifera and among species in genus Notholca (Rotifera) by computing parsimonious cladograms. All of the most-parsimonious cladograms generated for the ordinal level confirm the view that class Monogononta, superclass Eurotatoria, and phylum Rotifera are monophyletic. Species within the genus Notholca were separated into six groups (clades), but some species have been defined based on highly variable characters not reliably studied using cladistics. Therefore, phenetic studies are warranted, especially for species possessing caudal processes.  相似文献   

13.
The genus Nuphar consists of yellow-flowered waterlilies and is widely distributed in north-temperate bodies of water. Despite regular taxonomic evaluation of these plants, no explicit phylogenetic hypotheses have been proposed for the genus. We investigated phylogenetic relationships in Nuphar using morphology and sequences of the chloroplast gene matK and of the internal transcribed spacer (ITS) regions of nuclear ribosomal DNA. Two major lineages within Nuphar are consistently resolved with the morphological and molecular data sets. One lineage comprises New World taxa and the other represents a primarily Old World lineage. Relationships within the major lineages were poorly resolved by morphology and ITS, yet certain relationships were elucidated by all analyses. Most notable is the strong support for a monophyletic lineage of dwarf taxa and the alliance of the North American N. microphylla with the Eurasian taxa. Minor discordance between the independent cladograms is accounted for by hybridization. The common taxonomic practice of uniting all North American and Eurasian taxa under one species is not supported phylogenetically.  相似文献   

14.
The ever-larger data matrices resulting from continuing improvements in DNA sequencing techniques require faster and more efficient methods of phylogenetic analysis. Here we explore a promising new method, parsimony jackknifing, by analyzing a matrix comprising 2538 sequences of the chloroplast generbcL. The sequences included cover a broad taxonomic range, from cyanobacteria to flowering plants. Several parsimony jackknife analyses were performed, both with and without branch-swapping and multiple random addition sequences: 1) including all positions; 2) including only first and second codon positions; 3) including only third positions; and 4) using only transversions. The best resolution was obtained using all positions. Removal of third positions or transitions led to massive loss of resolution, although using only transversions somewhat improved basal resolution. While branch-swapping improved both resolution and the support found for several groups, most of the groups could be recovered by faster simple analyses. Designed to eliminate groups poorly supported by the data, parsimony jackknifing recognizes 1400 groups on the basis of allrbcL positions. These include major taxa such as green plants, land plants, flowering plants, monocots and eudicots. We include appendices of supported angiosperm families, as well as larger groups.  相似文献   

15.
The Briza complex comprises 23 species from South America, Mesoamerica and Europe. They constitute a monophyletic group because of the tendency of the spikelets to be dorsiventrally compressed. A cladistic analysis of the complex was performed using 32 characters from morphology. The terminal taxa were the species of the genera Briza, Calotheca, Microbriza, Poidium and Rhomboelytrum. Dactylis and Arrhenatherum were chosen to root the cladograms. Results of the cladistic analysis of the complex provide support for the ideas of Nicora and Rugolo (1981, Darwiniana 23(1), 279–309): Briza, Calotheca, Microbriza, Poidium and Rhomboelytrum are supported as monophyletic groups. Within Briza, only the Chascolytrum group appears monophyletic, while the Briza and Uniolae groups are paraphyletic. Poidium ambiguum, sometimes placed in Poa, is considered here as Poidium.  相似文献   

16.
Several recent studies using analyses of morphological characters have addressed the interrelationships of Osteoglossomorpha, a group that sometimes is considered the living sister group of all other living teleosts. Many characters used in these studies were found to be poorly defined, to be coded incorrectly or illogically, or to display more variation than was described. The goal of this study is to address these concerns and contribute generally to knowledge of the morphology and systematic relationships of osteoglossomorphs. Analysis of 72 characters (65 informative) scored for 20 genera resulted in two most parsimonious cladograms (171 steps, CI = 0.6433, CI = 0.6139 excluding uninformative characters, HI = 0.3977, HI = 0.3861 excluding uninformative characters; RI = 0.7782; RC = 0.5006). Osteoglossomorpha is supported by both synapomorphies and homoplasies, although its monophyly was not truly tested in this analysis (only a single outgroup, Elops , was included in the analysis). The only difference in the topologies of these cladograms is in the position of ?Lycoptera (recovered as either the sister group of all other osteoglossomorphs sampled or of ?Eohiodon +Hiodon ). ?Ostariostoma is recovered as the sister group of all non‐hiodontiform osteoglossomorphs. Mormyrids are the sister group of notopterids + osteoglossids. This clade has not been found in other recent analyses. Mormyrids and notopterids usually are considered more closely related to each other than to any other group; characters not included here support this relationship and future consideration of these characters must be made. Although almost completely dichotomous, many nodes of the resulting trees lack rigorous support. For example, ?Palaeonotopterus is interpreted as the sister group of all mormyrids sampled, although for this taxon only 22% of characters could be scored. © 2003 The Linnean Society of London. Zoological Journal of the Linnean Society , 2003, 137 , 1?100.  相似文献   

17.
Phylogenetic relationships among five cockroach families (Cryptocercidae, Polyphagidae, Blattidae, Blattellidae and Blaberidae) using seventeen species, were estimated based on the DNA sequences of the mitochondrial cytochrome oxidase subunit II (COII) gene. A cladogram inferred using the neighbour‐joining method indicated that Polyphagidae and Cryptocercidae are closely related to each other, and that these two groups are a sister group to the remaining cockroach families. The monophyly of this clade, however, was not strongly supported in terms of bootstrap percentages. Blaberidae and Blattellidae were shown to be sister groups as previously proposed, with Blattidae as a sister group to that clade. Non‐weighted and weighted parsimony analyses were also performed following analyses of nucleotide substitution patterns that indicated saturation of the COII gene among these taxa had occurred. These parsimonious cladograms suggested that Polyphagidae was the basal family, and Polyphaginae, including Cryptocercus as proposed by Grandcolas 1994a ), was not monophyletic. The inferred relationships among cockroach families (Polyphagidae, Cryptocercidae + (Blattidae + (Blattellidae + Blaberidae))) is partly in agreement with some previously published analyses. Additionally, based on molecular data, Asian and American Cryptocercus are suggested to have diverged from one another before the Oligocene (~20 mya).  相似文献   

18.
The phylogenetic position of the most speciose meiofaunal polychaete family, Nerillidae, has remained contentious. Recent hypotheses have generally focused on the fact that Nerillidae shares with Aciculata (a major polychaete subgroup) features such as compound chaetae, ventral buccal organ and short ventrolateral palps. Here we present the first phylogenetic analysis of Aciculata, together with Nerillidae, combining morphological and molecular data. We also include Aberrantidae, previously referred to or placed near to spiomorph polychaetes, but recently referred to Aciculata, possibly close to Nerillidae. The data sets of 24 terminals contain 53 morphological characters and nearly complete sequences of 18S rRNA. The sequences were analysed simultaneously with the morphological data by direct optimization in the program POY with a variety of parameter settings (costs of gaps: transversions: transitions). The various settings resulted in markedly different phylogenetic hypotheses, but on the basis of congruence (ILD) the results of two parameter settings were chosen. In all analyses, the three included nerillid species constituted a monophyletic group. Only two analyses provided fully resolved cladograms. The morphological analysis gave poor resolution and the position of the nerillids was equivocal. The two molecular‐based cladograms (minimizing ILD) were also poorly resolved, but one provided a position for nerillids next to Eunice pennata and Nothria conchilega, from the subgroup Eunicida within Aciculata. The two cladograms of the combined analyses (minimizing ILD) were fully resolved and placed nerillids in a terminal position next to Aberranta sp., within a clade of eunicidan species. The study showed that the analytical conditions for the homology assignment of 18S rRNA strongly influenced the phylogenetic results. The various previous proposals on the phylogenetic position of the Nerillidae are reviewed, some of which are in accordance with the results of the present study.  相似文献   

19.
Abstract. Myrmecia Fabricius is revised at species-group level. Nine groups are recognized: those of M.aberrans, M.cephalotes, M.gulosa, M.mandibularis, M.nigrocincta, M.picta, M.pilosula, M.tepperi and M. urens. A key to the species groups is provided, and worker diagnoses, illustrations and species lists are given for each. Eight groups are constituted much as in the previous classification of John Clark, but defined using new characters. Phylogenetic relationships are investigated, with six cladograms derived from four sets of data, each with a different outgroup. The most plausible cladograms suggest that: (1) the aberrans group is the sister group to the others; (2) the pilosula, tepperi and mandibularis groups constitute a monophyletic assemblage, though monophyly of the first two is not confirmed; (3) the gulosa, nigrocincta, urens and picta groups constitute a monophyletic assemblage, though monophyly of the picta group is not confirmed; (4) the phylogenetic position of the cephalotes group is unclear.  相似文献   

20.
Paleontological fit of different kinds of cladograms is considered using the ghost range method, the ghost range being the time gap between dates of supposed and paleontologically confirmed appearance of a taxon. The absolute and relative length of total ghost ranges in the published morphological and molecular cladograms and, in some cases, traditional (‘intuitive’) cladograms were calculated. Orders of winged insects as well as families of some of these orders were the terminal taxa of the cladograms (in all, 42 cladograms for 14 sets of terminal taxa). A new index is proposed to assess the relative amount of ghost ranges: GRI = 1-L0/LM, where L0 is the sum of ghost ranges in a particular cladogram and LM is the maximum possible sum of ghost ranges in a cladogram with the same set of terminal taxa. As in the previous studies (Rasnitsyn, 2000, 2005), calculations showed the intuitive cladograms to be clearly superior to both molecular and morphological ones in their stratigraphic fit. Another result, namely that molecular cladograms showed no advantage over morphological cladistics, was unexpected and apparently unexplainable. Additionally, the hypothesis of character devaluation resulting from computerized cladistic procedures (Rasnitsyn, 2002) was directly supported for the first time by our calculations.  相似文献   

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