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1.
An examination of previous morphological and molecular studies of strepsirhine systematics suggests a conflict between the two types of data. Cladistic analyses of morphological data have indicated that the Malagasy primate family Cheirogaleidae is the sister taxon of the Afro-Asian lorisiforms and that together, cheirogaleids and lorisiforms comprise a monophyletic clade that excludes the Malagasy lemuriforms. Molecular studies, on the other hand, have consistently found that cheirogaleids and lemuriforms together are monophyletic to the exclusion of lorisiforms. Both types of studies, however, have suffered from methodological weaknesses: the morphological studies looked at too few characters and the molecular studies looked at too few taxa. This study examines a large and diverse morphological data set as well as molecular data from a comprehensive sample of strepsirhine taxa. The data sets are considered independently and jointly. When they are analyzed independently, the morphological data give weak support, and the molecular data strong support, to the hypothesis of Malagasy primate monophyly. When the two data sets are combined in a single analysis, the results are decisive. The “total evidence” approach yields compelling support to the hypothesis that cheirogaleids and remaining Malagasy lemuriforms comprise a monophyletic assemblage that excludes lorisiforms. © 1994 Wiley-Liss, Inc.  相似文献   

2.
The phylogenetic relationships within the fungus gnat subfamily Mycetophilinae (Diptera) are addressed using a combined morphological and molecular approach. Twenty-four species, representing nine genera of the tribe Mycetophilini and 15 genera of the tribe Exechiini, were included in the study. Analyses include nucleotide sequences of mitochondrial (cytochrome oxidase I and 16S), and nuclear (18S and 28S rDNA) genes, in addition to 65 morphological characters. A combined parsimony analysis, including all characters, supports the monophyly of the subfamily Mycetophilinae and two of its tribes, Exechiini and Mycetophilini. There is also statistical support for a Mycetophila- group and a Phronia- group within the tribe Mycetophilini. The Phronia- group includes the genera Phronia , Macrobrachius and Trichonta . The Mycetophila- group includes the genera Mycetophila , Epicypta , Platurocypta , Sceptonia and Zygomyia . A Bayesian analysis based on the nucleotide sequences alone also support these clades within Mycetophilini except for the position of Dynatosoma which is recovered as the sister taxon to the Phronia- group. A somewhat different pattern, however, is observed for the tribe Exechiini – neither molecular data nor the combined data set support unambiguously any intergeneric relationships within Exechiini.  相似文献   

3.
Glass sponges (Class Hexactinellida) are important components of deep-sea ecosystems and are of interest from geological and materials science perspectives. The reconstruction of their phylogeny with molecular data has only recently begun and shows a better agreement with morphology-based systematics than is typical for other sponge groups, likely because of a greater number of informative morphological characters. However, inconsistencies remain that have far-reaching implications for hypotheses about the evolution of their major skeletal construction types (body plans). Furthermore, less than half of all described extant genera have been sampled for molecular systematics, and several taxa important for understanding skeletal evolution are still missing. Increased taxon sampling for molecular phylogenetics of this group is therefore urgently needed. However, due to their remote habitat and often poorly preserved museum material, sequencing all 126 currently recognized extant genera will be difficult to achieve. Utilizing morphological data to incorporate unsequenced taxa into an integrative systematics framework therefore holds great promise, but it is unclear which methodological approach best suits this task. Here, we increase the taxon sampling of four previously established molecular markers (18S, 28S, and 16S ribosomal DNA, as well as cytochrome oxidase subunit I) by 12 genera, for the first time including representatives of the order Aulocalycoida and the type genus of Dactylocalycidae, taxa that are key to understanding hexactinellid body plan evolution. Phylogenetic analyses suggest that Aulocalycoida is diphyletic and provide further support for the paraphyly of order Hexactinosida; hence these orders are abolished from the Linnean classification. We further assembled morphological character matrices to integrate so far unsequenced genera into phylogenetic analyses in maximum parsimony (MP), maximum likelihood (ML), Bayesian, and morphology-based binning frameworks. We find that of these four approaches, total-evidence analysis using MP gave the most plausible results concerning congruence with existing phylogenetic and taxonomic hypotheses, whereas the other methods, especially ML and binning, performed more poorly. We use our total-evidence phylogeny of all extant glass sponge genera for ancestral state reconstruction of morphological characters in MP and ML frameworks, gaining new insights into the evolution of major hexactinellid body plans and other characters such as different spicule types. Our study demonstrates how a comprehensive, albeit in some parts provisional, phylogeny of a larger taxon can be achieved with an integrative approach utilizing molecular and morphological data, and how this can be used as a basis for understanding phenotypic evolution. The datasets and associated trees presented here are intended as a resource and starting point for future work on glass sponge evolution.  相似文献   

4.
Dung beetle species belonging to the worldwide tribe Canthonini (Scarabaeidae) and occurring in Madagascar are all endemic to that island. The Malagasy Canthonini form three lineages, one of which is the group Longitarsi that includes five genera. The phylogenetic relationships of Malagasy Canthonini are not fully resolved and only few species of Longitarsi have been included in previous studies. Here we infer the phylogenetic relationships within the Longitarsi group using molecular data and together with morphological examination revise the systematics of the group. The five genera of the Longitarsi group form one monophyletic clade and thus we suggest the synonymization of the younger genera Sikorantus, Phacosomoides, Madaphacosoma and Aleiantus; with the oldest genus belonging to this clade Epactoides. We describe two new species: Epactoides jounii sp. n and Epactoides mangabeensis sp. n. Most of the species of Longitarsi inhabit the eastern rainforests, with very low local species diversity and highly restricted geographical ranges. In the group Longitarsi four species are wingless. The loss of wings has evolved at least twice, at high altitude along the mountain range.  相似文献   

5.
Using characters from mitochondrial DNA to construct maximum parsimony and maximum likelihood trees, we performed a phylogenetic analysis on representative species of 14 genera: 12 that belong to the treefrog family Rhacophoridae and two, Amolops and Rana, that are not rhacophorids. Our results support a phylogenetic hypothesis that depicts a monophyletic family Rhacophoridae. In this family, the Malagasy genera Aglyptodactylus, Boophis, Mantella, and Mantidactylus form a well-supported sister clade to all other rhacophorid genera, and Mantella is the sister taxon to Mantidactylus. Within the Asian/African genera, the genus Buergeria forms a well-supported clade of four species. The genera, except for Chirixalus, are generally monophyletic. An exception to this is that Polypedates dennysii clusters with species of Rhacophorus, suggesting that the taxonomy of the rhacophorids should be revised to reflect this relationship. Chirixalus is not monophyletic. Unexpectedly, there is strong support for Chirixalus doriae from Southeast Asia forming a clade with species of the African genus Chiromantis, suggesting that Chiromantis dispersed to Africa from Asia. Also, there is strong support for the sister taxon relationship of Chirixalus eiffingeri and Chirixalus idiootocus apart from other congeners.  相似文献   

6.
The molecular phylogenetics of decapod crustaceans has been based on sequence data from a limited number of genes. These have included rapidly evolving mitochondrial genes, which are most appropriate for studies of closely related species, and slowly evolving nuclear ribosomal RNA genes, which have been most useful for resolution of deep branches within the Decapoda. Here we examine the utility of the nuclear gene that encodes arginine kinase for phylogenetic reconstruction at intermediate levels (relationships among genera and families) within the decapod infraorder Brachyura (the true crabs). Analyses based on arginine kinase sequences were compared and combined with those for the mitochondrial cytochrome oxidase I gene. All of the genera in our taxon sample were resolved with high support with arginine kinase data alone. However, some of these genera were grouped into clades that are in conflict with recognized brachyuran families. A phylogeny based on cytochrome oxidase I was consistent with the arginine kinase phylogeny, but with weaker support. A recently proposed measure of phylogenetic informativeness indicated that arginine kinase was generally more informative than cytochrome oxidase I for relationships above the level of genus. Combined analysis of data from both genes provided strong support for clades that are in conflict with current assignments of genera to the families Epialtidae, Mithracidae, Pisidae, and Portunidae.  相似文献   

7.
The desert plated lizard ( Angolosaurus skoogi ), a 'sand sea' endemic of the northern Namib Desert, exhibits remarkable morphological convergence with other dune-dwelling lizards worldwide. This distinct ecomorphic condition sets Angolosaurus apart from the remaining genera in the family Gerrhosauridae. Indeed, a morphological phylogeny addressing generic relationships within the Cordyliformes (Cordylidae + Gerrhosauridae) identified Angolosaurus as the earliest diverging taxon among African gerrhosaurids. We re-evaluated the basal status of Angolosaurus , conducting a molecular phylogenetic analysis of the African and Madagascan gerrhosaurid genera. Our survey involved a comprehensive species-level comparison among the four nominal genera of mainland Africa ( Angolosaurus , Cordylosaurus , Tetradactylus and Gerrhosaurus ). Mitochondrial DNA sequence data from the cytochrome b , ND2, 12S and 16S rRNA genes were combined for analysis using both parsimony and maximum likelihood procedures. In contrast to the morphological hypothesis, our results do not depict Angolosaurus as the sister taxon to other African gerrhosaurids. Rather, the molecular analyses consistently place Angolosaurus within Gerrhosaurus , rendering the latter genus paraphyletic.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 78 , 253–261.  相似文献   

8.

Background  

Malagasy tenrecs belong to the Afrotherian clade of placental mammals and comprise three subfamilies divided in eight genera (Tenrecinae: Tenrec, Echinops, Setifer and Hemicentetes; Oryzorictinae: Oryzorictes, Limnogale and Microgale; Geogalinae: Geogale). The diversity of their morphology and incomplete taxon sampling made it difficult until now to resolve phylogenies based on either morphology or molecular data for this group. Therefore, in order to delineate the evolutionary history of this family, phylogenetic and dating analyses were performed on a four nuclear genes dataset (ADRA2B, AR, GHR and vWF) including all Malagasy tenrec genera. Moreover, the influence of both taxon sampling and data partitioning on the accuracy of the estimated ages were assessed.  相似文献   

9.
DNA sequences of the complete cytochrome b gene are shown to contain robust phylogenetic signal for the strepsirrhine primates (i.e., lemurs and lorises). The phylogeny derived from these data conforms to other molecular studies of strepsirrhine relationships despite the fact that uncorrected nucleotide distances are high for nearly all intrastrepsirrhine comparisons, with most in the 15%-20% range. Cytochrome b sequences support the hypothesis that Malagasy lemuriforms and Afro-Asian lorisiforms each comprise clades that share a sister- group relationship. A study (Adkins and Honeycutt 1994) of the cytochrome c oxidase subunit II (COII) gene placed one Malagasy primate (Daubentonia) at the base of the strepsirrhine clade, thereby suggesting a diphyletic Lemuriformes. The reanalysis of COII third- position transversions, either alone or in combination with cytochrome b third-position transversions, however, yields a tree that is congruent with phylogenetic hypotheses derived from cytochrome b and other genetic data sets.   相似文献   

10.
大蚊属Tipula Linnaeus,1758是大蚊科中种类最多的属,目前其单系性尚未得到全面验证.此外,长角大蚊亚属Tipula (Sivatipula) Alexander,1964因其极长的触角以及独有的精子泵结构,明显不同于大蚊属其他亚属,使其亚属的分类地位存在争议.本研究基于COI序列对19个大蚊属物种及5个其他属物种进行了系统发育分析,并计算了物种间的遗传距离.研究结果表明:(1)邻接树(NJ)和最大似然树(ML)均显示长角大蚊亚属与大蚊属其他亚属未形成单系,大蚊属的单系性没有得到支持;(2)基于遗传距离和系统发育分析并结合形态信息,结果显示长角大蚊亚属独立于大蚊属内其他亚属,应将其提升为属级分类单元.  相似文献   

11.
12.
Previous phylogenetic analyses of Ranunculales, which have mostly been focused on an individual family and were based on molecular data alone, have recovered three main clades within the order. However, support for relationships among these three clades was weak. Earlier hypotheses were often hampered by limited taxon sampling; to date less than one-tenth of the genera in the order have been sampled. In this study, we used a greatly enlarged taxon sampling (105 species, representing 99 genera of all seven families in the order). Our study is, furthermore, the first to employ morphology (65 characters) in combination with sequence data from four genomic regions, including plastid rbcL, matK and trnL-F, and nuclear ribosomal 26S rDNA to reconstruct phylogenetic relationships within Ranunculales. Maximum parsimony and Bayesian inference were performed on the individual and combined data sets. Our analyses concur with those of previous studies, but in most cases provide stronger support and better resolution for relationships among the three main clades retrieved. The first, comprised solely of the monogeneric family Eupteleaceae, is the earliest-diverging lineage. The second clade is composed exclusively of taxa of Papaveraceae, which is sister to the third clade, the core Ranunculales, comprising the other five families of the order. Circaeasteraceae and Lardizabalaceae form a strongly supported clade. Pteridophyllum is supported as sister to Hypecoum, contradicting the viewpoint that the former is the earliest-diverging genus in Papaveraceae. Glaucidium is basalmost in Ranunculaceae. Within this phylogenetic framework, the evolution of selected characters is inferred and diagnostic morphological characters at different taxonomic levels are identified and discussed. Based on both morphological and molecular evidence, a classification outline for Ranunculales is presented, including the proposal of two new subfamilies, Menispermoideae and Tinosporoideae in Menispermaceae and a new tribe, Callianthemeae, for the genus Callianthemum (Ranunculaceae).  相似文献   

13.
14.
In this paper we examine the phylogenetic relationships of the Octopoda utilizing molecular sequence data from the cytochrome c oxidase subunit I (COI) gene and compare results from analyses of molecular data with classifications and phylogenies based on previous morphological studies. Partial COI sequences (657 bp, excluding primers) were obtained from 28 species representing most of the diversity in the Order Octopoda, along with a sequence from the established sister taxon to the Octopoda, Vampyroteuthis infernalis. Our results exhibit a number of basic differences from inferences based on standard morphological data. We attempt to resolve these differences based on our confidence in various morphological features. An important finding is the failure of the molecular data to support the monophyly of the Octopodidae. This family contains over 90% of the species in the Suborder Incirrata and has always been difficult to define. Statistical tests constraining Octopodidae monophyly by use of parsimony and maximum-likelihood techniques suggest that all incirrates may be derived from octopodids.  相似文献   

15.
Phylogenetic relationships of the Malagasy and South Asian cichlids are investigated using nucleotide characters from two mitochondrial genes, a 544 bp region of the large ribosomal subunit (16S) and a 649 bp region of cytochrome c oxidase subunit I (COI). This is the first molecular analysis to include a thorough taxonomic sampling of all Malagasy-South Asian genera, and a near complete taxonomic inventory of all valid species. Parsimony analysis of the combined data set (1193 aligned nucleotide positions) results in a single, completely resolved phylogenetic hypothesis. Results of this analysis, and that based on more comprehensive taxonomic sampling across Cichlidae for 16S alone (554 bp for 73 taxa), indicate that the Malagasy cichlids are paraphyletic, whereas the Malagasy and South Asian cichlids comprise a monophyletic group. In both analyses, the African and Neotropical assemblages are monophyletic. The Malagasy-South Asian cichlids are not recovered as plesiomorphic members of the family in either analysis. Two major clades are recovered within the Malagasy-South Asian assemblage and given subfamilial rank, Etroplinae, comprising Paretroplus (Madagascar) and Etroplus (southern India and Sri Lanka), and Ptychochrominae, comprising Ptychochromis, Ptychochromoides, and Oxylapia, all endemic Malagasy genera. Placement of the endemic Malagasy genus Paratilapia is equivocal depending on the gene fragment(s) analyzed. Inter- and intrageneric relationships within Ptychochrominae and Etroplinae are presented and discussed. The hypothesis of relationships for Cichlidae based on nucleotide characters from 16S alone, arguably the most comprehensive and broadly sampled data set across all major geographic assemblages to date, is congruent with prevailing hypotheses regarding the sequence of Gondwanan fragmentation and a vicariance scenario to explain the current distribution of cichlid fishes.  相似文献   

16.
Notoriously slow rates of molecular evolution and convergent evolution among some morphological characters have limited phylogenetic resolution for the palm family (Arecaceae). This study adds nuclear DNA (18S SSU rRNA) and chloroplast DNA (cpDNA; atpB and rbcL) sequence data for 65 genera of palms and characterizes molecular variation for each molecule. Phylogenetic relationships were estimated with maximum likelihood and maximum parsimony techniques for the new data and for previously published molecular data for 45 palm genera. Maximum parsimony analysis was also used to compare molecular and morphological data for 33 palm genera. Incongruence among datasets was detected between cpDNA and 18S data and between molecular and morphological data. Most conflict between nuclear and cpDNA data was associated with the genus Nypa. Several taxa showed relatively long branches with 18S data, but phylogenetic resolution of these taxa was essentially the same for 18S and cpDNA data. Base composition bias for 18S that contributed to erroneous phylogenetic resolution in other taxa did not seem to be present in Palmae. Morphological data were incongruent with all molecular data due to apparent morphological homoplasy for Caryoteae, Ceroxyloideae, Iriarteae, and Thrinacinae. Both cpDNA and nuclear 18S data firmly resolved Caryoteae with Borasseae of Coryphoideae, suggesting that at least some morphological characters used to place Caryoteae in Arecoideae are homoplastic. In this study, increased character sampling seems to be more important than increased taxon sampling; a comparison of the full (65-taxon) and reduced (45- and 33-taxon) datasets suggests little difference in core topology but considerably more nodal support with the increased character sample sizes. These results indicate a general trend toward a stable estimate of phylogenetic relationships for the Palmae. Although the 33-taxon topologies are even better resolved, they lack several critical taxa and are affected by incongruence between molecular and morphological data. As such, a comparison of results from the 45- and 33-taxon trees offers the best available reference for phylogenetic inference on palms.  相似文献   

17.
Abstract Phylogenetic relationships among the genera of the large braconid wasp subfamily Microgastrinae were explored using DNA sequence data from the mitochondrial large ribosomal subunit (16S), nuclear large ribosomal subunit (28S) and mitochondrial cytochrome oxidase (COI) genes, along with morphological characters, both new and from previous studies. The taxonomic history of this group of wasps is reviewed, along with a critique of previous phylogenetic studies on the group. Molecular data were sampled from forty-six species representing twenty-six genera of microgastrines, plus three species representing the close outgroup taxa Cardiochilinae and Miracinae. Some 2300 base pairs of aligned sequence were obtained per taxon from the three genes. In addition, fifty-three morphological characters were coded for all known genera, including two undescribed genera, except Semionis Nixon (known from only a single male type specimen). Relationships among several groups of genera are clarified and challenge some major assumptions made in earlier classifications. In particular, it is clear that dependence on one or a few major morphological character systems oversimplifies relationships, and can lead to misleading results. Despite the large amount of data analysed, basal divergences within the subfamily remain poorly resolved and essentially unsupported in any rigorous statistical sense.  相似文献   

18.
The Archiborborinae is a diverse Neotropical subfamily of Sphaeroceridae, with many undescribed species. The existing generic classification includes three genera consisting of brachypterous species, with all other species placed in the genus Archiborborus. We present the first phylogenetic hypothesis for the subfamily based on morphological, molecular, and combined datasets. Morphological data include 53 characters and cover all valid described taxa (33 species in 4 genera) in the subfamily, as well as 83 undescribed species. Molecular data for five genes (mitochondrial 12S rDNA, cytochrome c oxidase subunit I, and cytochrome B, and nuclear alanyl-tRNA synthetase and 28S rDNA) were obtained for 21 ingroup taxa. Data support the separation of the Archiborborinae from the Copromyzinae, with which they were formerly combined. Analyses support consistent groups within the subfamily, but relationships between groups are poorly resolved. The validity of the brachypterous genera Penola Richards and Frutillaria Richards is supported. The former genus Archiborborus Duda is paraphyletic, and will be divided into monophyletic genera on the basis of this work. Aptery and brachyptery have evolved multiple times in the subfamily. Antrops Enderlein, previously including a single brachypterous species, is a senior synonym of Archiborborus.  相似文献   

19.
The phylogenetic relationships of 39 species of Eneopterinae crickets are reconstructed using four molecular markers (16S rRNA, 12S rRNA, cytochrome b, 18S rRNA) and a large morphological data set. Phylogenetic analysis via direct optimisation of DNA sequence data using parsimony as optimality criterion is done for six combinations of weighting parameter sets in a sensitivity analysis. The results are discussed in a twofold purpose: first, in term of significance of the molecular markers for phylogeny reconstruction in Ensifera, as our study represents the first molecular phylogeny performed for this insect suborder at this level of diversity; second, in term of corroboration of a previous phylogeny of Eneopterinae, built on morphological data alone. The four molecular markers all convey phylogenetic signal, although variously distributed on the tree. The monophyly of the subfamily, that of three over five tribes, and of 10 over 13 genera, are recovered. Finally, previous hypotheses on the evolution of acoustic devices and signals in the Eneopterinae clade are briefly tested, and supported, by our new data set.  相似文献   

20.
Total evidence: molecules, morphology, and the phylogenetics of cichlid fishes   总被引:10,自引:0,他引:10  
We present a most comprehensive phylogenetic analysis of the family Cichlidae. New data analyzed include mitochondrial 16S rRNA sequences and two nuclear loci (Tmo-M27 and Tmo-4C4) for a large taxonomic sampling with emphasis on South American species. We also incorporate a published morphological data set for a total evidence analysis. Character congruence among mitochondrial (74 taxa) and nuclear data (50 taxa) was high. However, partition-homogeneity tests suggest significant heterogeneity among molecular and morphological data. In agreement with results obtained from molecular data alone, total evidence analysis (1,460 characters for 34 taxa) supports a robust phylogenetic hypothesis for the family Cichlidae that is congruent with drift-vicariance events associated with the fragmentation of Gondwana. Our analyses confirm the placement of Malagasy/Indian cichlids as the most basal lineages, with a sister-group relationship to the monophyletic African and Neotropical clades. Total evidence suggests that the controversial African genus Heterochromis is at the base of the African radiation. Among more than 50 Neotropical genera analyzed, Retroculus is identified as the basal taxon, with successive branching of Cichla, Astronotus, geophagines (including crenicichlines) + chaetobranchines, and cichlasomines + heroines. Relative rate tests applied to mitochondrial DNA suggest significantly higher rates of genetic variation in Neotropical than in African taxa, and both mitochondrial and nuclear sequences show that rate heterogeneity among Neotropical lineages is confined to the geophagine cichlids.  相似文献   

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