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1.
Marine butterflyfishes (10 genera, 114 species) are conspicuously beautiful and abundant animals found on coral reefs worldwide, and are well studied due to their ecological importance and commercial value. Several phylogenies based on morphological and molecular data exist, yet a well-supported molecular phylogeny at the species level for a wide range of taxa remains to be resolved. Here we present a molecular phylogeny of the butterflyfishes, including representatives of all genera (except Parachaetodon) and at least one representative of all commonly cited subgenera of Chaetodon (except Roa sensuBlum, 1988). Genetic data were collected for 71 ingroup and 13 outgroup taxa, using two nuclear and three mitochondrial genes that total 3332 nucleotides. Bayesian inference, parsimony, and maximum likelihood methods produced a well-supported phylogeny with strong support for a monophyletic Chaetodontidae. The Chaetodon subgenera Exornator and Chaetodon were found to be polyphyletic, and the genus Amphichaetodon was not the basal sister group to the rest of the family as had been previously proposed. Molecular phylogenetic analysis of data from 5 genes resolved some clades in agreement with previous phylogenetic studies, however the topology of relationships among major butterflyfish groups differed significantly from previous hypotheses. The analysis recovered a clade containing Amphichaetodon, Coradion, Chelmonops, Chelmon, Forcipiger, Hemitaurichthys, Johnrandallia, and Heniochus. Prognathodes was resolved as the sister to all Chaetodon, as in previous hypotheses, although the topology of subgeneric clades differed significantly from hypotheses based on morphology. We use the species-level phylogeny for the butterflyfishes to resolve long-standing questions regarding the use of subgenera in Chaetodon, to reconstruct molecular rates and estimated dates of diversification of major butterflyfish clades, and to examine global biogeographic patterns.  相似文献   

2.
Reconstructing the evolution of complex bird song in the oropendolas   总被引:1,自引:0,他引:1  
The elaborate songs of songbirds are frequent models for investigating the evolution of animal signals. However, few previous studies have attempted to reconstruct historical changes in song evolution using a phylogenetic comparative approach. In particular, no comparative studies of bird song have used a large number of vocal characters and a well-supported, independently derived phylogeny. We identified 32 features in the complex vocal displays of male oropendolas (genera Psarocolius, Gymnostinops, and Ocyalus) that are relatively invariant within taxa and mapped these characters onto a robust molecular phylogeny of the group. Our analysis revealed that many aspects of oropendola song are surprisingly evolutionarily conservative and thus are potentially useful characters for reconstructing historical patterns. Of the characters that varied among taxa, nearly two thirds (19 of 29) showed no evidence of evolutionary convergence or reversal when mapped onto the tree, which was reflected in a high overall consistency index (CI = 0.78) and retention index (RI = 0.88). Some reconstructed patterns provided evidence of selection on these signals. For example, rapid divergence of the songs of the Montezuma oropendola, Gymnostinops montezuma, from those of closely related taxa suggests the recent influence of strong sexual selection. In general, our results provide insights into the mode of vocal evolution in songbirds and suggest that complex vocalizations can provide information about phylogeny. Based on this evidence, we use song characters to estimate the phylogenetic affinities of three oropendola taxa for which molecular data are not yet available.  相似文献   

3.
4.
The sequences of the internal transcribed spacer (ITS) region of 18S–26S nrDNA for a sample of 16 taxa from theInuleae s. str. and two outgroup taxa are analysed cladistically with PAUP. A consensus tree of the four most parsimonious cladograms is presented. Three different tests of cladogram stability are conducted (Bremer support, parsimony jackknifing and bootstrapping); all tests indicate a high degree of support for the basal nodes of the tree. The ITS phylogeny of the tribe is compared with previous hypotheses based on morphological data. The position ofAnisopappus as sister group to the rest of the tribe is supported by the molecular data, but the proposed subdivision ofInuleae s. str. into a paleate grade group and an epaleate clade is not. The interpretation of the character evolution of, e.g. receptacular paleae and pappus features within the tribe is discussed.  相似文献   

5.
This study presents a new phylogeny of erigonine spiders with emphasis on genera from the Neotropics. Thirty‐nine exemplar taxa representing mostly Neotropical genera were added to a global sample of 31 erigonine and 12 outgroup exemplar taxa analyzed in a previous study. These 82 taxa were coded for 176 (172 informative) mostly morphological characters. Eighty‐one characters were identical to or modified from the 73 (67 informative) characters included in a previous study; the remaining 95 characters are new. The complete data set includes 70 erigonine exemplars representing 65 genera, seven nonerigonine linyphiid exemplars, and five exemplars representing four araneoid families in the outgroup. Cladistic analysis resulted in a single most parsimonious tree (L =904, CI = 0.23, RI = 0.58; uninformative characters excluded: L = 900, CI = 0.23). This paper explores the implications of the new topology for the evolution of several characters of interest in erigonine evolution. The phylogeny implies that the desmitracheate condition is a synapomorphy of erigonines, with a reversal to the haplotracheate condition in one large clade within Erigoninae. We infer that the loss of the paracymbium in Neotropical erigonines occurred twice and may have progressed by different evolutionary pathways. Our phylogeny differs markedly from the previous cladistic hypothesis of erigonine relationships. We investigate how the addition of characters and taxa (alone and together) have altered the earlier hypothesis of erigonine phylogeny. We conclude that topological changes from the previous study to the current one are largely the result of adding and modifying characters, not adding taxa. Continuous Jackknife Function (CJF) analysis predicts that the inclusion of additional character data will continue to imply changes in the relationships among taxa in our analysis.  相似文献   

6.
Ribosomal RNA sequences and cladistic analysis were used to infer a phylogeny for eight bryophyte taxa. Portions of the cytoplasmic large (26S-like) and small (18S-like) subunit ribosomal RNA genes were sequenced for three marchantioid liverworts (Asterella, Conocephalum, and Riccia), three mosses (Atrichum, Fissidens, and Plagiomnium), and two hornworts (Phaeoceros and Notothylas). Cladistic analysis of these data suggests that the hornworts are the sister group to the mosses, the mosses and hornworts form a clade that is sister to the tracheophytes, and the liverworts form a clade sister to the other land plants. These results differ from previous cladistic analyses based on morphology, ultrastructure, and biochemistry, wherein the mosses alone are sister group to the tracheophytes. We conclude that cladistic analysis of molecular data can provide an independent data set for the study of bryophyte phylogeny, but the differences between the molecular and morphological results are a topic for further investigation.  相似文献   

7.
The ordinal level phylogeny of the Arachnida and the suprafamilial level phylogeny of the Opiliones were studied on the basis of a combined analysis of 253 morphological characters, the complete sequence of the 18S rRNA gene, and the D3 region of the 28S rRNA gene. Molecular data were collected for 63 terminal taxa. Morphological data were collected for 35 exemplar taxa of Opiliones, but groundplans were applied to some of the remaining chelicerate groups. Six extinct terminals, including Paleozoic scorpions, are scored for morphological characters. The data were analyzed using strict parsimony for the morphological data matrix and via direct optimization for the molecular and combined data matrices. A sensitivity analysis of 15 parameter sets was undertaken, and character congruence was used as the optimality criterion to choose among competing hypotheses. The results obtained are unstable for the high-level chelicerate relationships (except for Tetrapulmonata, Pedipalpi, and Camarostomata), and the sister group of the Opiliones is not clearly established, although the monophyly of Dromopoda is supported under many parameter sets. However, the internal phylogeny of the Opiliones is robust to parameter choice and allows the discarding of previous hypotheses of opilionid phylogeny such as the "Cyphopalpatores" or "Palpatores." The topology obtained is congruent with the previous hypothesis of "Palpatores" paraphyly as follows: (Cyphophthalmi (Eupnoi (Dyspnoi + Laniatores))). Resolution within the Eupnoi, Dyspnoi, and Laniatores (the latter two united as Dyspnolaniatores nov.) is also stable to the superfamily level, permitting a new classification system for the Opiliones.  相似文献   

8.
A recent total evidence analysis of the position of cetaceans(whales, dolphins and porpoises and extinct relatives) amongmammals indicated that the phylogeny of these taxa remains poorlyresolved. Molecular data show that 1) the order Artiodactyla(even-toed ungulates) is paraphyletic unless whales are includedwithin it and 2) that the traditional relationships of cladeswithin Artiodactyla are not supported. This controversy alsoaffects the position of a wholly extinct clade, Mesonychia,which has been argued to be the group of terrestrial mammalsmost closely related to whales. Here I update a previous totalevidence analysis by adding several hundred new informativemolecular characters from the literature. Even with the additionof these characters the phylogeny remains unresolved. All mostparsimonious trees, however, indicate a paraphyletic Artiodactylawith conflict existing over the exact sister taxon of Cetacea.Congruence between different equally parsimonious cladogramsand the stratigraphic record as measured using the modifiedManhattan Stratigraphic Measure shows that all of the competingtopologies, including those with a paraphyletic Artiodactyla,are significantly congruent with the stratigraphic record. Infossil taxa cladistic optimization can be used as an alternativeto "argument from design" (Lauder, 1996) to reconstruct behaviorand soft tissues that do not fossilize or osteological charactersthat have not preserved. In certain scenarios of cetacean phylogeny,optimization indicates that taxa such as the archaic whalesAmbulocetus and Pakicetus, and possibly mesonychians, are morecorrectly reconstructed without hair.  相似文献   

9.
The phylogeny of Crocodylia offers an unusual twist on the usual molecules versus morphology story. The true gharial (Gavialis gangeticus) and the false gharial (Tomistoma schlegelii), as their common names imply, have appeared in all cladistic morphological analyses as distantly related species, convergent upon a similar morphology. In contrast, all previous molecular studies have shown them to be sister taxa. We present the first phylogenetic study of Crocodylia using a nuclear gene. We cloned and sequenced the c-myc proto-oncogene from Alligator mississippiensis to facilitate primer design and then sequenced an 1,100-base pair fragment that includes both coding and noncoding regions and informative indels for one species in each extant crocodylian genus and six avian outgroups. Phylogenetic analyses using parsimony, maximum likelihood, and Bayesian inference all strongly agreed on the same tree, which is identical to the tree found in previous molecular analyses: Gavialis and Tomistoma are sister taxa and together are the sister group of Crocodylidae. Kishino-Hasegawa tests rejected the morphological tree in favor of the molecular tree. We excluded long-branch attraction and variation in base composition among taxa as explanations for this topology. To explore the causes of discrepancy between molecular and morphological estimates of crocodylian phylogeny, we examined puzzling features of the morphological data using a priori partitions of the data based on anatomical regions and investigated the effects of different coding schemes for two obvious morphological similarities of the two gharials.  相似文献   

10.
SYNOPSIS. Our interpretation of the evolution of development,morphology, and diversity of multicellular animals hinges ona clear understanding of the phylogenetic relationships of metazoans.Currently, the field of metazoan phylogeny is in a state offlux, with new hypotheses of metazoan relationships emergingfrom analyses of 18S rDNA sequence data. Some of these analyseshave been limited in the numbers of taxa analyzed, others, withnumerous taxa analyzed, have not resolved deep level branchingpatterns, and all are hampered by properties of the 18S geneitself. Corroboration of the results from 18S rDNA analysescan come from additional molecular data sets, such as highlyconserved nuclear coding genes, mitochondria gene order, orgene duplication events. The enormous task of data accumulationfor additional molecular data from many representative taxacan most efficiently be undertaken in a coordinated, collaborativeeffort among different lab groups. Ultimately, a combined analysisof several independent data sets will be possible and may providea more stable, robust phylogeny for the Metazoa.  相似文献   

11.
The phylogeny of the Tubificidae, and of most of its subfamilies and some of its genera, is revisited, on the basis of sequences of 18S ribosomal DNA in a selection of species. Forty-six new 18S sequences of Naididae (6), Tubificidae (37), Phreodrilidae (1), Lumbriculidae (1), and Enchytraeidae (1) are reported and aligned together with corresponding sequences of 21 previously studied taxa. The 18S gene of Insulodrilus bifidus provides the first molecular evidence that phreodrilids are closely related to tubificids, corroborating previous conclusions based on morphology. The data further support the monophyletic status of Tubificidae, provided that the "Naididae" is regarded a part of this family; "naidids" may not even constitute a monophyletic group. It is thus suggested that the family name Naididae is formally suppressed as a junior synonym of the Tubificidae. The 18S gene also resolves a number of relationships within the tubificids. Among the subfamilies, Tubificinae is supported, Rhyacodrilinae and Phallodrilinae are revealed as nonmonophyletic, and Limnodriloidinae remains unresolved. Most tubificid genera tested for monophyly are corroborated by the data, only one (Tubifex) is refuted, and two (Tubificoides and Limnodriloides) are unresolved from other taxa. It is concluded that it will be valuable to expand the taxonomic sampling for 18S rDNA in clitellates, and in annelids in general, as this is likely to improve the resolution at many levels. However, it will be equally important to combine the annelid 18S data with other gene sequences and nonmolecular characters, to estimate the phylogeny of these common and diverse worms with greater precision.  相似文献   

12.
The evolutionary history of Branchiopoda (Crustacea) traditionally has attracted considerable interest due to the diversity of the group. Recently molecular methods have been applied to the study of branchiopod systematics with some success, but central questions, such as the phylogenetic position of Laevicaudata and Notostraca, and the intrinsic cladoceran phylogeny, remain unanswered. We examined the phylogeny of Branchiopoda by using two genes, mitochondrial 16S rRNA and nuclear 28S rRNA, which previously have seen little use for inferring branchiopod phylogeny. The number of ingroup taxa included was 42, representing all eight extant branchiopod orders. The data were analyzed using parsimony, maximum likelihood, and Bayesian Inference of phylogeny. Some higher-level taxa were supported in all analyses of the combined data: Phyllopoda, Cladoceromorpha, Cladocera, and Gymnomera. Other higher-level taxa were not supported in any trees: Diplostraca and Conchostraca. A case is made for a possible diplostracan ingroup position of Notostraca based on our data and on previously published molecular and morphological evidence. The recent discovery of a Devonian branchiopod, which is morphologically an intermediate between a notostracan and a 'conchostracan', is congruent with a diplostracan ancestry of Notostraca.  相似文献   

13.
Variation in rates of molecular evolution now appears to be widespread. The demonstration that body size is correlated with rates of molecular evolution suggests that physiological and ecological factors may be involved in molecular rate variation, but large-scale comparative studies are still lacking. Here, we use complete cytochrome b sequences from 85 species of tube-nosed seabirds (order Procellariiformes) and 5 outgroup species of penguins (order Sphenisciformes) to test for an association between body mass and rates of molecular evolution within the former avian order. Cladistic analysis of the 90 sequences estimates a phylogeny largely consistent with the traditional taxonomy of the Procellariiformes. The Diomedeidae, Procellariidae, and Pelecanoididae are monophyletic, while the Hydrobatidae are basal and paraphyletic. However, the two subfamilies within the Hydrobatidae (Hydrobatinae and Oceanitinae) are monophyletic. A likelihood ratio test detects significant deviation from clocklike evolution in our data. Using a sign test for an association between body mass and branch length in the seabird phylogeny, we find that larger taxa tend to have shorter terminal branch lengths than smaller taxa. This observation suggests that rates of mitochondrial DNA evolution are slower for larger taxa. Rate calibrations based on the fossil record reveal concordant body size effects. We interpret these results as evidence for a metabolic rate effect, as the species in this order exhibit large differences in metabolic rates, which are known to be highly correlated with body mass in this group. Our results support previous findings of body size effects and show that this effect can be significant even within a single avian order. This suggests that even lineage-specific molecular clocks may not be tenable if calibrations involve taxa with different metabolic rates.   相似文献   

14.
Rubus is a taxonomically difficult group and cytological data are expected hopefully to gain insight into the relationships of the genus. In this study the chromosome numbers and karyotypes of 18 taxa from sect. Idaeobatus and 10 taxa from sect. Malachobatus were investigated. Among them, the chromosome numbers of 10 taxa and karyotypes of 26 taxa were reported for the first time and mixoploidy was observed new in the genus. The chromosomes are small in size with a length of less than 3 µm and metacentric (about 90%) or submetacentric. All taxa have karyotypes of “1A” except R. cockburnianus, R. innominatus and R. ellipticus var. obcordatus, which have karyotypes of “2A”. No aneuploids were found in all the 28 taxa studied. Plants of sect. Idaeobatus have diploids with 2n=2x=14, except R. idaeopsis (2n=3x=21) and R. parvifolius (A mixoploid of 2n=2x=14 and 2n=4x=28). However, plants of sect. Malachobatus have tetraploids with 2n=4x=28, except for R. buergeri with 2n=8x=56. In addition, conspicuous karyotype differences existed within the 18 taxa belonging to 11 of 7 subsections in sect. Idaeobatus, and the differences between some species within subsections are greater than that between subsections, while uniform karyotypes within subsections and variable karyotypes between subsections were observed in six of 13 subsections in sect. Malachobatus represented by 10 taxa. Systematic values of the cytological data were discussed for some cases when applicable to the two sections.  相似文献   

15.
Gastrotrichs are meiobenthic free-living aquatic worms whose phylogenetic and intra-group relationships remain unclear despite some attempts to resolve them on the base of morphology or molecules. In this study we analysed complete sequences of the 18S rRNA gene of 15 taxa (8 new and 7 published) to test numerous hypotheses on gastrotrich phylogeny and to verify whether controversial interrelationships from previous molecular data could be due to the short region available for analysis and the poor taxa sampling. Data were analysed using both maximum likelihood and Bayesian inference. Results obtained suggest that gastrotrichs, together with Gnathostomulida, Plathelminthes, Syndermata (Rotifera + Acanthocephala), Nemertea and Lophotrochozoa, comprise a clade Spiralia. Statistical tests reject phylogenetic hypotheses regarding Gastrotricha as close relatives of Nematoda and other Ecdysozoa or placing them at the base of bilaterian tree close to acoels and nemertodermatides. Within Gastrotricha, Chaetonotida and Macrodasyida comprise two well supported clades. Our analysis confirmed the monophyly of the Chaetonotidae and Xenotrichulidae within Chaetonida as well as Turbanellidae and Thaumastodermatidae within Macrodasyida. Mesodasys is a sister group of the Turbanellidae, and Lepidodasyidae appears to be a polyphyletic group as Cephalodasys forms a separate lineage at the base of macrodasyids, whereas Lepidodasys groups with Neodasys between Thaumastodermatidae and Turbanellidae. To infer a more reliable Gastrotricha phylogeny many species and additional genes should be involved in future analyses.  相似文献   

16.
Karyological information about Iberian Genista species is limited because of their wide geographical distribution. It is a major factor in the understanding of a genus whose genetic evolution is mostly related to aneuploidy and euploidy. The chromosome numbers of the following taxa have been counted: G. carpetana subsp. carpetana (n = 20), G. cinerascens (n = 12), G. micrantha (n = 18), G. mugronensis subsp. rigidissima (n = 18), G. ramosissima (2n = 48) and G. tinctoria (n = 24). The previously-assumed uniformity of chromosome number (n = 24) for all the subspecies of G. cinerea is supported here by data from subspp. murcica and speciosa. In G. florida, a new chromosome number, n = 23, has been found for both subspecies (florida and polygaliphylla). A discussion of the discrepancies between these data and previous ones is included. A new level of ploidy has been found in G. tuurnefortii subsp. tournefortii (n = 32). The data stress the necessity of obtaining chromosomal information from a number of plants of a taxon before its characteristic number is clear, and indicate that more chromosomal data will help the understanding of the cytological diversity within taxa in Genista.  相似文献   

17.
The phylogeny of Oedogoniales was investigated by using nuclear 18S rDNA sequences. Results showed that the genus Oedocladium, as a separated clade, was clustered within the clade of Oedogonium; whereas the genus Bulbochaete was in a comparatively divergent position to the other two genera. The relationship among the species of Oedogonium was discussed, focusing on ITS-2 phylogeny analyzed combining with some morphological characteristics. Our results showed that all the dioecious nannandrous taxa involved in this study were resolved into one clade, while all the monocious taxa were clustered into another clade as a sister group to the former. The report also suggests that the dioecious macrandrous taxa form a paraphyly and could be more basally situated than the dioecious nannandrous and the monoecious taxa by means of molecular phylogeny and morphotype investigations.  相似文献   

18.
This study investigated nudibranch phylogeny on the basis of 18S rDNA sequence data. 18S rDNA sequence data of 19 taxa representing the major living orders and families of the Nudibranchia were analyzed. Representatives of the Cephalaspidea, Anaspidea, Gymnomorpha, Prosobranchia, and Pulmonata were also sequenced and used as outgroups. An additional 28 gastropod sequences taken from GenBank were also included in our analyses. Phylogenetic analyses of these more than 50 gastropod taxa provide strong evidence for support of the monophyly of the Nudibranchia. The monophyly of the Doridoidea, Cladobranchia, and Aeolidoidea within the Nudibranchia are also strongly supported. Phylogenetic utility and information content of the 18S rDNA sequences for Nudibranchia, and Opisthobranchia in general, are examined using the program SplitsTree as well as phylogenetic reconstructions using distance and parsimony approaches. 0Results based on these molecular data are compared with hypotheses about nudibranch phylogeny inferred from morphological data.  相似文献   

19.

Background  

The phylogeny of Eumalacostraca (Crustacea) remains elusive, despite over a century of interest. Recent morphological and molecular phylogenies appear highly incongruent, but this has not been assessed quantitatively. Moreover, 18S rRNA trees show striking branch length differences between species, accompanied by a conspicuous clustering of taxa with similar branch lengths. Surprisingly, previous research found no rate heterogeneity. Hitherto, no phylogenetic analysis of all major eumalacostracan taxa (orders) has either combined evidence from multiple loci, or combined molecular and morphological evidence.  相似文献   

20.
In order to place a newly discovered species Antigracilus costatus gen. sp. n. from the Lower Cretaceous Yixian Formation (China) and to assess previously unplaced fossil taxa, we investigated the relationships of extant and extinct lineages of Histeridae based on three data sets: (i) 69 morphological characters belonging to 48 taxa (representing all 11 subfamilies and 15 of 17 tribes of modern Histeridae); (ii) partitioned alignment of 6030 bp from downloaded nucleotide sequences (28S, CAD, COI, 18S) of 50 taxa (representing 10 subfamilies and 15 of 17 tribes of modern Histeridae); and (iii) a combined morphological and molecular dataset for 75 taxa. Phylogenetic analyses of the morphology and combined matrices recovered the new Lower Cretaceous taxon as a sister group to remaining Histeridae and it is placed in †Antigracilinae subfam. n. †Antigracilinae constitutes the earliest record of Histeridae from the Lower Cretaceous Yixian Formation (∼125 Myr), backdating the minimum age of the family by 25 Myr from the earliest Cenomanian (~99 Myr) to the Barremian of the Cretaceous Period. Our molecular phylogeny supports Histeridae to be divided into seven different clades, with currently recognised subfamilies Abraeinae (sensu lato), Saprininae, Chlamydopsinae, and Histerinae (sensu lato) recovered as monophyletic, while Dendrophilinae, Onthophilinae, and Tribalinae are polyphyletic taxa. The Burmese amber species †Pantostictus burmanicus Poinar & Brown is placed as a sister group to the tribe Plegaderini (Abraeinae) and was assigned as a new tribe Pantostictini trib. n. Both molecular and combined phylogenies recovered the subfamilies Trypanaeinae and Trypeticinae deeply within the subfamily Abraeinae (sensu lato), and they are downgraded into Trypanaeini stat. n. and Trypeticini stat. n.  相似文献   

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