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1.
The phylogeny of the fungus gnat tribe Exechiini (Diptera: Mycetophilidae) is reconstructed based on the combined analysis of five nuclear (18S, two parts of 28S, CAD, EF1α) and two mitochondrial (12S, COI) gene markers. According to known fossil record, and recent higher‐level phylogenies, the tribe constitutes the most apomorphic, distinctly monophyletic clade of the family Mycetophilidae. The tribe originated in the Paleogene and apparently quickly diversified in the Neogene with an unusual rapid radiation of complex male terminalia. Earlier attempts to reconstruct the phylogeny of the tribe, based on both morphology and molecular methods, have not yielded reliable hypotheses, neither in terms of resolution nor in terms of support for major clades. Increased taxon sampling and wider gene sampling have been suggested to achieve better phylogenetic resolution. Aiming at this, we present new phylogenies, for the first time with all known genera and subgenera of Exechiini represented. While many terminal intergeneric relationships are well supported, both in maximum likelihood and in Bayesian analyses, most of the major, deeper clades remain poorly supported. We suggest that a rapid radiation event close to the root may be causing the low resolution at this level in the phylogeny. This contrasts parallel phylogenies of the older subfamilies and tribes of the family Mycetophilidae, where traditional clades have usually been recovered with high support. Further in‐depth studies into the evolutionary history of the tribe are needed to enlighten and coalesce the specific phenomena driving their unique morphological, genetic and phylogeographic histories.  相似文献   

2.
The first comprehensive phylogenetic analyses of the most diverse subfamily of plant bugs, Mirinae, is presented in this study, for 110 representative taxa based on total evidence analysis. A total of 85 morphological characters and 3898 bp of mitochondrial (16S, COI) and nuclear (18S, 28S) sequences were analysed for each partitioned and combined dataset based on parsimony, maximum likelihood and Bayesian inference. Major results obtained in this study include monophyly of the tribe Mecistoscelini. The largest tribe, Mirini, was recovered as polyphyletic, and Stenodemini was recovered as paraphyletic. The clade of Stenodemini + Mecistoscelini is the sister group of the remaining Mirinae. The monophyly of two complexes composed of superficially similar genera were tested; the Lygus complex was recovered as nonmonophyletic, and the Adelphocoris–Creontiades–Megacoelum complex was confirmed to be monophyletic. The generic relationships of the main clades within each tribe based on the phylogeny, as well as their supported morphological characters, are discussed.  相似文献   

3.
A comprehensive higher‐level phylogeny of diving beetles (Dytiscidae) based on larval characters is presented. Larval morphology and chaetotaxy of a broad range of genera and species was studied, covering all currently recognized subfamilies and tribes except for the small and geographically restricted Hydrodytinae, where the larva is unknown. The results suggest several significant conclusions with respect to the systematics of Dytiscidae including the following: monophyly of all currently recognized subfamilies, although Dytiscinae when considered in a broad context is rendered paraphyletic by Cybistrinae; currently recognized tribes are monophyletic except for Agabini, Hydroporini and Laccornellini; inter‐subfamily and inter‐tribe relationships generally show weak support, except for a few well supported clades; three distinct clades are recognized within Dytiscinae [Dytiscini sensu lato (i.e. including the genera Dytiscus Linnaeus and Hyderodes Hope), Hydaticini sensu lato, and Cybistrini]; and recognition of Pachydrini as a distinct tribe. Other less robust results include: Methlini sister to the rest of Hydroporinae; relative basal position of Laccornini, Hydrovatini and Laccornellini within Hydroporinae; close relationship of Agabinae and Copelatinae; Matinae nested deep within Dytiscidae, as sister to a large clade including Colymbetinae, Coptotominae, Lancetinae and Dytiscinae sensu lato; the sister‐group relationship of Agabetini and Laccophilini is confirmed. The results presented here are discussed and compared with previous phylogenetic hypotheses based on different datasets, and the evolution of some significant morphological features is discussed in light of the proposed phylogeny. All suprageneric taxa are diagnosed, including illustrations of all relevant synapomorphies, and a key to separate subfamilies and tribes is presented, both in traditional (paper) format and as an online Lucid interactive identification key.  相似文献   

4.
Melastomataceae is a tropical family of 4500–5000 species divided into nine tribes. The largest tribe, Miconieae, is composed of approximately 2200 species in 30 genera and is found exclusively in the Neotropics. Previous phylogenetic analyses of the Miconieae have suggested that many of the genera are derived from a paraphyletic Miconia. However, these analyses only included six species of the large genus Leandra, so its phylogenetic affinities remained unclear. As currently defined Leandra is characterized by acute petals and terminal inflorescences, but some species of Miconia, Clidemia and Ossaea also have these characters. In this study, we present an analysis of nrITS sequence data for a sample of 63 species of Leandra. The genus is clearly resolved as polyphyletic, but some distinct and well‐supported clades exist. Some of these partially correspond to sections recognized in the nineteenth century by Cogniaux, or to geographic distribution. The distribution of seed structure characters is better correlated with the phylogeny than traditional characters, such as petal morphology. Seed appendages in Leandra have evolved independently at least four times. © The Willi Hennig Society 2007.  相似文献   

5.
The phylogeny of the green algal Order Dasycladales was inferred by maximum parsimony and Bayesian analyses of chloroplast‐encoded rbcL sequence data. Bayesian analysis suggested that the tribe Acetabularieae is monophyletic but that some genera within the tribe, such as Acetabularia Lamouroux and Polyphysa Lamouroux, are not. Bayesian analysis placed Halicoryne Harvey as the sister group of the Acetabularieae, a result consistent with limited fossil evidence and monophyly of the family Acetabulariaceae but was not supported by significant posterior probability. Bayesian analysis further suggested that the family Dasycladaceae is a paraphyletic assemblage at the base of the Dasycladales radiation, casting doubt on the current family‐level classification. The genus Cymopolia Lamouroux was inferred to be the basal‐most dasycladalean genus, which is also consistent with limited fossil evidence. Unweighted parsimony analyses provided similar results but primarily differed by the sister relationship between Halicoryne Lamouroux and Bornetella Munier‐Chalmas, thus supporting the monophyly of neither the families Acetabulariaceae nor Dasycladaceae. This result, however, was supported by low bootstrap values. Low transition‐to‐transversion ratios, potential loss of phylogenetic signal in third codon positions, and the 550 million year old Dasycladalean lineage suggest that dasyclad rbcL sequences may be saturated due to deep time divergences. Such factors may have contributed to inaccurate reconstruction of phylogeny, particularly with respect to potential inconsistency of parsimony analyses. Regardless, strongly negative g1 values were obtained in analyses including all codon positions, indicating the presence of considerable phylogenetic signal in dasyclad rbcL sequence data. Morphological features relevant to the separation of taxa within the Dasycladales and the possible effects of extinction on phylogeny reconstruction are discussed relative to the inferred phylogenies.  相似文献   

6.
Some of the morphological characters used in Porifera taxonomy have often been shown to be inconsistent. In the present study, we tested the phylogenetic coherence of currently used taxonomic characters of the calcarean genus Clathrina. For this, 20 species of Clathrina and three other calcinean genera (Ascandra, Guancha, and Leucetta) were sequenced for the ITS and D2 region of the 28S ribosomal DNA. Maximum‐likelihood and maximum‐parsimony algorithms were used to reconstruct phylogenetic trees. Deep divergences were observed in our tree and Clathrina was shown to be paraphyletic. The major split in our topology showed a clear‐cut distinction between sponges with and without tetractine spicules. Moreover, a group of yellow‐coloured Clathrina was clearly separated from the remaining white‐coloured species. Our results show that the presence of diactines, water‐collecting tubes, the degree of cormus anastomosis, and actine shapes do not correlate with the major clades of the calcinean phylogeny. On the other hand, the presence of tripods, the absence of tetractines, and the presence of spines in the apical actine of tetractines seem to be good synapomorphies for clades in our tree. Our results demonstrate that skeleton characters can be reliably used in higher level taxonomy in Clathrinida. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163 , 1026–1034.  相似文献   

7.
The Menispermaceae family contains ca. 72 genera with 450 species that are almost entirely tropical. Its phylogeny at the tribal level has never been examined using molecular data. Here we used DNA sequences of the chloroplast matK gene and trnL-F regions, and the nuclear ITS region to study the delimitation and position of the tribe Menispermeae within the family and its subtribal monophyletic groups. Family-wide phylogenetic analyses of the chloroplast data produced two strongly supported clades. The first clade contains two subclades: Coscinieae including Arcangelisia and Anamirta, and Tinosporeae sensu lato including Fibraureae, supported by morphological characters, such as traits of the cotyledon, stylar scar and embryo. The second clade consists of the tribes Menispermeae sensu DC. and Tiliacoreae Miers. All our analyses surprisingly recognized that tribe Menispermeae is not monophyletic unless tribe Tiliacoreae is included, suggesting that characters of cotyledon and stylar scar are very important for the infrafamilial classification, and that endosperm presence vs. absence was over-emphasized in traditionally tribal division of the family. Our topologies indicate a secondary loss of endosperm. The monophyly of two subtribes of the tribe Menispermeae, Stephaniinae and Cissampelinae, is supported by the cpDNA and ITS data, as well as by morphological characters, including aperture types and shapes, and colpal membrane features of pollen grains, and sepal number of male flowers. The Cocculinae was recognized as a paraphyletic group containing the remaining genera of the tribe Menispermeae.  相似文献   

8.
Leucophyllum is one of the most remarkable endemic genera of North American deserts, with its simultaneous bloom of showy purple flowers. With Eremogeton and probably Capraria it forms part of tribe Leucophylleae. Leucophyllum has 16 species distributed mostly throughout the Chihuahuan and Tehuacán deserts. The three genera were sampled to investigate the phylogenetic relationships among them and to test the monophyly of Leucophyllum, based on plastid DNA (trnL‐F, rps16) and nuclear ribosomal (nr)DNA (internal transcribed spacer) sequences. Bayesian inference and maximum‐likelihood analyses confirmed that tribe Leucophylleae is monophyletic and formed by the three Neotropical genera. Separate (plastid DNA and nrDNA) and combined analyses retrieved Leucophyllum as paraphyletic, with L. mojinense as the sister species to the rest of the species in the tribe and Capraria spp. nested in one of two clades of Leucophyllum. Further monographic work is needed to identify the defining characters and limits of the genera, but we suggest that L. mojinense, with its different vegetative architecture, distinctive flowers and dissimilar distribution could be placed in its own genus. Each of the two clades in Leucophyllum could be considered a genus in its own right, and Capraria and Eremogeton can be recognized as independent genera, as they are at present. Leucophyllum ambiguum, the type species of the genus, belongs to one of the clades so the species of the other could be considered members of a new genus. The only diagnostic character detected at present is a ventricose corolla tube in one of the clades in Leucophyllum and a pressed corolla tube in the other. © 2013 The Linnean Society of London  相似文献   

9.
Tiger beetles are a remarkable group that captivates amateur entomologists, taxonomists and evolutionary biologists alike. This diverse clade of beetles comprises about 2300 currently described species found across the globe. Despite the charisma and scientific interest of this lineage, remarkably few studies have examined its phylogenetic relationships with large taxon sampling. Prior phylogenetic studies have focused on relationships within cicindeline tribes or genera, and none of the studies have included sufficient taxon sampling to conclusively examine broad species patterns across the entire subfamily. Studies that have attempted to reconstruct higher‐level relationships of Cicindelinae have yielded conflicting results. Here, we present the first taxonomically comprehensive molecular phylogeny of Cicindelinae to date, with the goal of creating a framework for future studies focusing on this important insect lineage. We utilized all available published molecular data, generating a final concatenated dataset including 328 cicindeline species, with molecular data sampled from six protein‐coding gene fragments and three ribosomal gene fragments. Our maximum‐likelihood phylogenetic inferences recover Cicindelinae as sister to the wrinkled bark beetles of the subfamily Rhysodinae. This new phylogenetic hypothesis for Cicindelinae contradicts our current understanding of tiger beetle phylogenetic relationships, with several tribes, subtribes and genera being inferred as paraphyletic. Most notably, the tribe Manticorini is recovered nested within Platychilini including the genera Amblycheila Say, Omus Eschscholtz, Picnochile Motschulsky and Platychile Macleay. The tribe Megacephalini is recovered as paraphyletic due to the placement of the monophyletic subtribe Oxycheilina as sister to Cicindelini, whereas the monophyletic Megacephalina is inferred as sister to Oxycheilina, Cicindelini and Collyridini. The tribe Collyridini is paraphyletic with the subtribes Collyridina and Tricondylina in one clade, and Ctenostomina in a second one. The tribe Cicindelini is recovered as monophyletic although several genera are inferred as para‐ or polyphyletic. Our results provide a novel phylogenetic framework to revise the classification of tiger beetles and to encourage the generation of focused molecular datasets that will permit investigation of the evolutionary history of this lineage through space and time.  相似文献   

10.
The Augochlorini Beebe is a New World tribe of bees comprising 663 described species. Relationships among the genera of this monophyletic tribe remain uncertain. Here I provide a comprehensive phylogeny using morphological and molecular information. In all, 54 Augochlorini species plus 16 outgroups and 3017 molecular and 105 morphological characters were analysed. Sequences for four genes were analysed using Bayesian inference, maximum likelihood and parsimony. Morphological characters were taken from a literature review and analysed alone and in combination with molecular data using parsimony. The monophyly of Augochlorini and most genera is confirmed, with divergence of the main lineages of the tribe around 55–20 Ma. Seven clades were supported by most analyses and are here treated as genus‐level groups, as follows (combined analysis topology): (Corynura group, (Chlerogella group, (Rhinocorynura group, (Augochloropsis, (Megaloptidia group, (Neocorynura group, (Augochlora group, Megalopta group))))))). According to this topology, dim‐light foraging and cleptoparasitism arose three times in the tribe. According to my hypothesis, the diversification of Augochlorini may have begun as a response to vicariant events, including the split of the Neotropical/Andean regions and marine transgressions in the Amazon region.  相似文献   

11.
Phytophagous ladybird beetles of the tribe Epilachnini are a cosmopolitan, species‐rich group of significant economic importance as pests of agricultural crops. The tribe is well characterized morphologically and clearly monophyletic, but very little is known about its internal phylogenetic relationships and their genus‐level taxonomy. In order to infer the evolutionary history of Epilachnini, test its monophyly and provide a phylogeny‐based classification, we assembled a comprehensive dataset, consisting of four DNA markers (18S and 28S rRNA and 16S, COI mtDNA) and a matrix of 104 morphological characters for 153 species of Epilachnini representing all previously recognised genera, ~11% of the known species, and 14 outgroup taxa. Molecular, morphological and combined datasets were analysed using maximum likelihood, parsimony and Bayesian inference. Bayes factors and Approximately Unbiased tests (AU) were used to compare alternative phylogenetic hypotheses of unconstrained and backbone‐constrained analysis. Only 14 of the 25 included genera were recovered monophyletic, as originally defined. Afidentula Kapur, Afidenta Dieke, Afissula Kapur, Epilachna Chevrolat, Henosepilachna Li Toxotoma Weise and Mada Mulsant are shown to be poly‐ or paraphyletic; Chnootriba Chevrolat, Subafissa Bielawski, Lalokia Szawaryn & Tomaszewska and Papuaepilachna Szawaryn & Tomaszewska form monophyletic groups within larger clades of genus level. All of these genera are redefined here. The two largest genera of Epilachnini, Epilachna Chevrolat and Henosepilachna Li were represented by multiple monophyletic clades, which we described as new genera: Chazeauiana Tomaszewska & Szawaryn gen.n. ; Diekeana Tomaszewska & Szawaryn gen.n .; Fuerschia Tomaszewska & Szawaryn gen.n. and Ryszardia Tomaszewska & Szawaryn gen.n . The following new synonyms are proposed: Afissa Dieke (=Afissula Kapur); Henosepilachna Li in Li & Cook (=Subafissa Bielawski); Papuaepilachna Szawaryn & Tomaszewska (=Lalokia Szawaryn & Tomaszewska). This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:440E7FA4‐C859‐47E0‐8335‐30D478CBA8FA .  相似文献   

12.
Phylogenetic analyses of 33 genera of Rubiaceae were performed using morphological and a few chemical characters. Parsimony analysis based on 29 characters resulted in eight equally parsimonious trees, with a consistency index of 0.40 and a retention index of 0.69. These results were compared to a phylogenetic analysis of the same genera based on chloroplast DNA restriction site data. There are discrepancies between the two analyses, but if we consider groupings reflected in the present classification there is much congruency. With the exception of four genera, all the genera are positioned in the same group of taxa in the two analyses. Clades of taxa representing three of the four subfamilies (~the Antirheoideae, ~the Rubioideae, and the ~Ixoroideae) are monophyletic, while the fourth subfamily Cinchonoideae is shown to be paraphyletic. Both analyses support a widened tribe Chiococceae, including the former subtribe Portlandiinae (Condamineeae). Furthermore, in both analyses the tribe Hamelieae is placed outside the subfamily Rubioideae where it is now housed. In search for the most plausible sister group to the Rubiaceae, the genus Cinchona (Rubiaceae) was analyzed together with 13 genera of the Loganiaceae, Nerium (Apocynaceae), and Exacum (Gentianaceae). Cornus (Comaceae), Olea (Oleaceae), and these two genera together were used as outgroups. The analysis, including 25 characters, 16 taxa, and with Cornus and Olea together as an outgroup, resulted in four equally parsimonious trees, with a consistency index of 0.53 and a retention index of 0.62. The non-Loganiaceae taxa Cinchona (Rubiaceae), Nerium (Apocynaceae), and Exacum (Gentianaceae) were all found to have their closest relatives within the Loganiaceae indicating that the Loganiaceae are paraphyletic and ought to be reclassified. As a result of the morphological data the most plausible sister group to the Rubiaceae is the tribe Gelsemieae of the Loganiaceae.  相似文献   

13.
We present here the first molecular phylogeny of tribe Diseae (Orchidoideae: Orchidaceae). Nuclear ribosomal ITS1, 5.8S rDNA, and ITS2 sequences were compared for 30 Diseae, 20 Orchideae, and four Cranichideae and Diurideae outgroups. ITS - rDNA sequences exhibited a transition:transversion ratio of 1.3 and extensive ITS length polymorphism. Phylogenetic analyses using maximum parsimony identified seven major core orchidoid groups. The branching order of the five Diseae and two Orchideae clades was weakly supported but indicated paraphyly of Diseae, with Disperis sister to the rest, followed by successive divergence of Brownleea, Disinae, Coryciinae sensu stricto (s.s.), Satyriinae, and terminated by Orchidinae plus Habenariinae. Within the monophyletic Disinae, Herschelia and Monadenia were nested within a paraphyletic Disa and clustered with D. sect. Micranthae. Within monophyletic Satyriinae, Satyridium rostratum plus Satyrium bicallosum was sister to the rest of Satyrium, and then Satyrium nepalense plus S. odorum was distinct from a cluster of six species. Coryciinae are paraphyletic because Disperis is sister to all other core orchidoids. Coryciinae s.s. are sister to Satyriinae plus Orchideae, with Pterygodium nested within Corycium. Maximum likelihood analysis supported possible affinities among Disinae, Brownleeinae, and Coryciinae but did not support monophyly of Diseae or an affinity between Disinae and Satyriinae. Morphological characters are fully congruent with the well-supported groups identified in the ITS phylogeny.  相似文献   

14.
The relationships among the genera and tribal groupings of Riodininae with five forewing radial veins, and between these and tribes with four forewing radial veins, were examined using a phylogenetic analysis. Using the type species from all sixteen genera in the tribal groupings Eurybiini, Mesosemiini and incertae sedis (a presumed paraphyletic group of loosely related genera), and representatives from the four forewing radial‐veined riodinine tribes, thirty‐five new and traditional characters were coded from adult ecology, wing venation and pattern, the adult head and body, male and female genitalia, and early stage ecology and morphology. The majority of characters are illustrated. Phylogenetic analysis of these data produced five equally most parsimonious cladograms using equal weights and after successive weighting. The strict consensus of these confirms the monophyly of Eurybiini and Mesosemiini as currently conceived, but also indicates several higher‐level relationships not previously hypothesized. Mesosemiini is here more broadly defined to also include the entire incertae sedis section, and the tribe is divided into Mesosemiina, for the previously delimited Mesosemiini plus Eunogyra and Teratophthalma, and Napaeina, subtr.n. for the incertae sedis section minus these two genera. The following hypothesis of relationships is tentatively proposed for the basal clades of Riodininae: Mesosemiini + (Eurybiini + remainder of Riodininae). These new hypotheses, and the characters supporting them, are discussed and compared with those previously proposed.  相似文献   

15.
The tribe Abrotrichini (five genera and 14 living species) is a small clade within the speciose subfamily Sigmodontinae (Rodentia, Cricetidae), representing one of the extant successful radiations of mammals at southern high latitudes of the Neotropics. Its distribution is mostly Andean, reaching its greatest diversity in southern Argentina and Chile. We evaluate the phylogenetic relationships within this tribe through parsimony and Bayesian approaches based on 99 morphological characters (including 19 integumental characters, 38 skull characters, 31 dental characters, three postcranial skeletal characters, seven from the male accessory glands and phallus and one from the digestive system) and six molecular markers (one mitochondrial and five nuclear). We include representatives of all, except one, of the currently recognized species of living Abrotrichini plus one fossil form. Based on total evidence, we recovered a primary division between the genus Abrothrix and a group including the long‐clawed Abrotrichini, Chelemys, Geoxus, Notiomys and Pearsonomys. Both clades are recognized and named here as subtribes. The large degree of morphological variation observed within Abrothrix suggests that species in the genus fall into four groups, which we recognize as subgenera. In addition, the two known species of Chelemys do not form a monophyletic group, and Geoxus was recovered as paraphyletic with respect to Pearsonomys. To reconcile classification and phylogenetics, we describe a new genus for Chelemys macronyx and include Pearsonomys as a junior synonym of Geoxus. Our results highlight the importance of both morphology and molecules in resolving the phylogenetic relationships within this tribe. Based on biogeographical analyses, we hypothesize that Abrotrichini originated in south‐western South America by vicariance and then diversified mostly by successive dispersal events.  相似文献   

16.
Deparia, including the previously recognized genera Lunathyrium, Dryoathyrium (=Parathyrium), Athyriopsis, Triblemma, and Dictyodroma, is a fern genus comprising about 70 species in Athyriaceae. In this study, we inferred a robust Deparia phylogeny based on a comprehensive taxon sampling (~81% of species) that captures the morphological diversity displayed in the genus. All Deparia species formed a highly supported monophyletic group. Within Deparia, seven major clades were identified, and most of them were characterized by inferring synapomorphies using 14 morphological characters including leaf architecture, petiole base, rhizome type, soral characters, spore perine, and leaf indument. These results provided the morphological basis for an infra‐generic taxonomic revision of Deparia.  相似文献   

17.
Aim To establish the phylogeny and geographical origin of the genera of the diving beetle tribe Hyphydrini in order to investigate the origin of differences in geographical range size, intrageneric species‐richness and morphological disparity. In particular, we tested the hypothesis that the geographically restricted, species‐poor and morphologically deviating genera found in the Cape Region of South Africa are a paraphyletic pool of ‘primitive’ Hyphydrini, from which the morphologically more uniform, species‐rich and geographically widespread genera have originated. Location Worldwide, with special reference to the Cape Region of South Africa. Methods We constructed a genus‐level molecular phylogeny of 10 of the 14 known genera of Hyphydrini, including the five endemic to the Cape Region, using sequences from four gene fragments (two mitochondrial, rrnL and cox1; and two nuclear, 18S rRNA and histone 3, c. 2200 bp). Phylogenies were built with Bayesian methods, and linearized using penalized likelihood. Morphological disparity was characterized by correspondence analysis of a data matrix of 21 binary characters. We compare morphological disparity among groups using distance to the global and local centroids and the total range of morphospace occupied. Geographical range was estimated using the number of 6° longitude × 8° latitude Universal Transverse Mercator squares known to contain any species of each genus. Results Hyphydrini is made up of four well supported clades of similar relative genetic divergence: (1) Hyphydrus (Old World plus Australasia, 133 species), (2) the five endemic genera of the Cape Region, sister to Hovahydrus (Madagascar) (10 species), (3) Desmopachria (America, 92 species), and (4) two Oriental genera (Microdytes and Allopachria, 68 species). The morphological disparity within the Cape Region lineage has apparently increased with time, with the two genera closest to the global centroid paraphyletic and basal with respect to the three more recent, morphologically deviating genera. Differences in the number of species between each of the four lineages were not significant. The correlation between the number of species in each lineage and geographical range extent was highly significant, with the low species number of the Cape Region (six) well within the 95% confidence interval of the regression. Main conclusions Contrary to expectations, the species‐poor, morphologically deviating endemic genera of the Cape Region are not a ‘primitive’ relictual pool from which the widespread, species‐rich and morphologically uniform genera have originated. The morphological disparity within the Cape lineage has increased with time, and the apparent lack of species‐level diversification disappears when species–area relationships are considered. A major unanswered question is why one of the four main lineages of Hyphydrini has remained restricted to a very reduced area (the Cape Region), but despite this evolved the highest degree of morphological diversity seen in the tribe.  相似文献   

18.
We present a comprehensively sampled three‐gene phylogeny of the monophyletic Forcipulatacea, one of three major lineages within the crown‐group Asteroidea. We present substantially more Southern Hemisphere and deep‐sea taxa than were sampled in previous molecular studies of this group. Morphologically distinct groups, such as the Brisingida and the Zoroasteridae, are upheld as monophyletic. Brisingida is supported as the derived sister group to the Asteriidae (restricted), rather than as a basal taxon. The Asteriidae is paraphyletic, and is broken up into the Stichasteridae and four primary asteriid clades: (1) a highly diverse boreal clade, containing members from the Arctic and sub‐Arctic in the Northern Hemisphere; (2) the genus Sclerasterias; (3) and (4) two sister clades that contain asteriids from the Antarctic and pantropical regions. The Stichasteridae, which was regarded as a synonym of the Asteriidae, is resurrected by our results, and represents the most diverse Southern Hemisphere forcipulatacean clade (although two deep‐sea stichasterid genera occur in the Northern Hemisphere). The Labidiasteridae is artificial, and should be synonymized into the Heliasteridae. The Pedicellasteridae is paraphyletic, with three separate clades containing pedicellasterid taxa emerging among the basal Forcipulatacea. Fossils and timing estimates from species‐level phylogeographic studies are consistent with prior phylogenetic hypotheses for the Forcipulatacea, suggesting diversification of basal taxa in the early Mesozoic, with some evidence for more widely distributed ranges from Cretacous taxa. Our analysis suggests a hypothesis of an older fauna present in the Antarctic during the Eocene, which was succeeded by a modern Antarctic fauna that is represented by the recently derived Antarctic Asteriidae and other forcipulatacean lineages. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 162 , 646–660.  相似文献   

19.
Recent molecular studies have elucidated the phylogeny of Compositae tribe Arctotideae, and found it to contain two, well supported, monophyletic subtribes, Arctotidineae and Gorteriinae, as well as some polyphyletic and problematic genera. On the basis of this new information, it may now be possible to identify diagnostic characters and synapomorphies to support the groupings defined within Arctotideae. Pollen characters have been shown to be particularly variable in Compositae. This paper aims to investigate the utility of those characters in the context of recent molecular phylogenies, in order to determine synapomorphic and diagnostic characters in Arctotideae. The pollen of each genus is described, illustrated with scanning electron micrographs, and optimised on a phylogeny of the tribe. Many pollen characters were found to be very informative when considered in the context of the current best estimate of phylogenetic relationships. Pollen morphology provides synapomorphies for clades at a number of hierarchical levels within Arctotideae, including the two subtribes, Arctotidinae and Gorteriinae, the grouping of Eremothamnus and Hoplophyllum, and smaller clades. It also supports the exclusion of Platycarpha from the tribe. The plesiomorphic palynological state for the tribe is discussed. Particular attention is paid to the evolution of different patterns of lophae (surface ridges). A single origin for the lophate condition is proposed as the most parsimonious mode of evolution in Arctotideae.  相似文献   

20.
The neotropical butterfly genus Hamadryas Hübner comprises 20 species that exhibit an intriguing variation in their natural history traits. Although revised in 1983, no phylogenetic hypothesis was presented: the first phylogenetic hypothesis is estimated here based on 93 characters and including species from the three other genera in the tribe Ageroniini. The phylogeny is used to test the monophyly of the genus, establish the sister group of Hamadryas and identify its apomorphies. The tree allows the inference of patterns of character change in sound production and sexual dimorphism. Implied weights show that Hamadryas is monophyletic and corroborate Ectima Doubleday as a sister genus. Previously suggested subgenera for Hamadryas were non‐monophyletic, with the exception of the laodamia clade, supported by the presence of a complete sterigma. Sound production is inferred to be a derived condition in Hamadryas that has been lost in the laodamia clade. This, plus the presence of androconial organs and sexual dimorphism in the laodamia clade, suggests a shift in sexual recognition signalling. Furthermore, the phylogeny indicates that the colour pattern of males in the laodamia clade is novel, supporting a Darwinian origin of sexual dimorphism.  相似文献   

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