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1.
In this study we investigated the phylogenetic relationships within the ‘higher land birds’ by parsimony analysis of nucleotide DNA sequences obtained from the two nuclear, protein-coding genes, c- myc and RAG-1. Nuclear genes have not previously been used to address this phylogenetic question. The results include high jackknife support for a monophyletic Apodiformes (including the Trochilidae). This arrangement was further supported by the observation of an insertion of four amino acids in the c- myc gene in all apodiform taxa. Monophyly was also inferred for each of the two piciform groups Galbulae and Pici. Within Pici, the Capitonidae was found to be paraphyletic, with the New World barbets more closely related to the Ramphastidae than to the Old World barbets. Another clade with high jackknife support consists of the Upupidae, Phoeniculidae and Bucerotidae. The families Momotidae and Todidae, and Coraciidae and Brachypteraciidae, respectively, also form well supported monophyletic clades. The results are inconclusive regarding the monophyly of the orders Coraciiformes and Piciformes, respectively.  相似文献   

2.
For a nearly complete set of species of Erythronium (Liliaceae), we examined two plastid loci (the rps16 intron and the 5′ trnK intron, excluding the matK exon), one nuclear locus (nrITS) and morphology to evaluate species relationships and that of Erythronium to Amana, the putatively most closely allied genus. A matrix of morphological characters was developed through observation of around 900 living and herbarium specimens; evolution of these was examined using character optimization on the combined (total‐evidence) tree. Parsimony methods were used to examine the morphological and molecular data sets produced, both separately and in combination, with Bayesian methods also used on the molecular data sets. These established that the genus is probably sister to Amana (although most analyses placed Amana inside Erythronium) and that Tulipa is sister to the pair of Erythronium and Amana. Within Erythronium, there are three strongly supported geographically distinct clades: (1) Eurasian and (2) eastern and (3) western North American. Separation of species in these three clades is less clear, particularly among the western North American taxa. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, ●●, ●●–●●.  相似文献   

3.
Analyses of rRNA and rDNA among Metazoa result in a hypothesis of a sistergroup relationship of Brachiopoda and certain spiralian taxa, whereas analyses of morphological data imply that Brachiopoda show affinities to Deuterostomia within the Radialia. Regarding Brachiopoda as a derived spiralian taxon must be followed by a reinterpretation of the evolution of distinct brachiopod morphological characters—like cleavage pattern, coelom or larva. The experimental insertion of a monophyletic taxon consisting of Brachiopoda and Phoronida into a widely accepted phylogenetic tree of Spiralia leads to the hypothesis that at least trimeric organization, mesosomal tentacular apparatus and heterogeneously assembled metanephridia are products of convergent evolution in Brachiopoda plus Phoronida and Deuterostomia. The hypothesis of a radialian nature of Brachiopoda and Phoronida, as implied by morphological data, remains as the most parsimonious possibility to explain the evolution of seven regarded characters (cleavage pattern, larva, tentacular apparatus, coelom, metameric segmentation, metanephridia and chaetae) in Brachiopoda. Due to the conflicting results of both methods a hitherto undetected systematical problem is discussed possibly hindering data comparability. If the course of evolution can principally be inferred from the information preserved in recent and fossil animals, the results should be congruent in the analyses of both, molecular and morphological data.  相似文献   

4.
Abstract. Because the taxonomy of marine sponges is based primarily on morphological characters that can display a high degree of phenotypic plasticity, current classifications may not always reflect evolutionary relationships. To assess phylogenetic relationships among sponges in the order Verongida, we examined 11 verongid species, representing six genera and four families. We compared the utility of morphological and molecular data in verongid sponge systematics by comparing a phylogeny constructed from a morphological character matrix with a phylogeny based on nuclear ribosomal DNA sequences. The morphological phylogeny was not well resolved below the ordinal level, likely hindered by the paucity of characters available for analysis, and the potential plasticity of these characters. The molecular phylogeny was well resolved and robust from the ordinal to the species level. We also examined the morphology of spongin fibers to assess their reliability in verongid sponge taxonomy. Fiber diameter and pith content were highly variable within and among species. Despite this variability, spongin fiber comparisons were useful at lower taxonomic levels (i.e., among congeneric species); however, these characters are potentially homoplasic at higher taxonomic levels (i.e., between families). Our molecular data provide good support for the current classification of verongid sponges, but suggest a re-examination and potential reclassification of the genera Aiolochroia and Pseudoceratina . The placements of these genera highlight two current issues in morphology-based sponge taxonomy: intermediate character states and undetermined character polarity.  相似文献   

5.
Morphological and molecular phylogenetic studies show that there is a close relationship between Coffea and Psilanthus. In this study we reassess species relationships based on improved species sampling for Psilanthus, including P. melanocarpus, a species that shares morpho‐taxonomic characters of both genera. Analyses are performed using parsimony and Bayesian inference, on sequence data from four plastid regions [trnL–F intron, trnL–F IGS, rpl16 intron and accD–psa1 intergenic spacer (IGS)] and the internal transcribed spacer (ITS) region of nuclear ribosomal DNA (ITS 1/5.8S/ITS 2). Several major lineages with geographical coherence, as identified in previous studies based on smaller and larger data sets, are supported. Our results also confirm previous studies showing that the level of sequence divergence between Coffea and Psilanthus species is negligible, particularly given the much longer branch lengths separating other genera of tribe Coffeeae. There are strong indications that neither Psilanthus nor Coffea is monophyletic. Psilanthus melanocarpus is nested with the CoffeaPsilanthus clade, which means that there is only one critical difference between Coffea and Psilanthus; the former has a long‐emergent style and the latter a short, included style. Based on these new data, in addition to other systematically informative evidence from a broad range of studies, and especially morphology, Psilanthus is subsumed into Coffea. This decision increases the number of species in Coffea from 104 to 124, extends the distribution to tropical Asia and Australasia and broadens the morphological characterization of the genus. The implications for understanding the evolutionary history of Coffea are discussed. A group of closely related species is informally named the ‘Coffea liberica alliance’. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 167 , 357–377.  相似文献   

6.
《Mycoscience》2014,55(6):456-461
Two new species, Melanoleuca leucopoda and M. porphyropoda, are described based on collections made from Shenyang City, Liaoning Province, China. Melanoleuca leucopoda is mainly characterized by its whitish stipe with fibrils and oblong spores with elongated warts. Melanoleuca porphyropoda differs from all other Melanoleuca species in lacking cystidia and in having decurrent gills and a purplish stipe. The sequences of internal transcribed spacer regions (ITS1-5.8S-ITS2) of Melanoleuca species were analyzed and the results indicated that two new species clustered into two clades and differed from the other species of the genus. The combination of morphological and molecular data confirmed that the two fungi are new species. The morphological similarity of the new species to other species of Melanoleuca and the systematic position of the two species based on molecular data are also discussed.  相似文献   

7.
8.
Phylogenetic relationships are complex within the Lithospermeae, a large subgroup of the Boraginaceae s.str. The relationships of New World Lasiarrhenum, Macromeria, Nomosa, Onosmodium, Perittostoma, and Psilolaemus to subcosmopolitan and much larger Lithospermum have not been critically investigated in the recent past. No molecular data on the phylogeny of these genera and Lithospermum have so far been published. We investigated the relationships within Lithospermeae using three loci (nuclear ITS plus 5.8S rRNA, chloroplast trnL-F-spacer, and trnS-G-spacer) and micromorphological character traits (pollen, nutlets). Lithospermum s.l. constitutes the sistergroup of Asian Ulugbekia and is monophyletic only when its American segregates “Macromeria”, monotypic Nomosa, and Onosmodium are included. Both the African and the South American species groups of Lithospermum are monophyletic, but North American representatives are not resolved in a single clade. Morphological characters that have been considered as important for generic delimitation in the past (such as large, yellow corollas without faucal scales, particular pollen types, coarsely veined leaves, shrubby habit) have evolved in at least two only distantly related lineages within Lithospermum s.l. The reduction of American “Macromeria”, Nomosa, and Onosmodium as well as Asian Ulugbekia under Lithospermum is proposed to render the latter monophyletic. This redefined Lithospermum s.l. appears to have undergone a type of recent “island radiation” in the Americas, reflected in a morphological diversity far exceeding that found in the Old World.  相似文献   

9.
The endemic elaphoglossoid ferns, Elaphoglossum dimorphum, E. nervosum and Microstaphyla furcata of St Helena, form a closely related group within section Lepidoglossa when analysed phylogenetically using sequences from the chloroplast trnL intron (partial) and trnL-F intergenic spacer. Microstaphyla furcata, traditionally placed in its own genus, is clearly shown to belong to Elaphoglossum confirming the previous transfer of this species to Elaphoglossum as E. bifurcatum. There is hardly any trnL-F sequence divergence between the species, in fact sequences of E. nervosum and E. dimorphum are identical. These results are consistent with the possible origin of E. dimorphum as a hybrid between E. bifurcatum and E. nervosum or with the view that the three species are the result of a recent radiation. The potential conflict between phylogenetic and morphological distinctness in determining species conservation priorities is discussed.  相似文献   

10.
Metalasia is a genus in tribe Gnaphalieae (Asteraceae), endemic to South Africa and with its main distribution in the Cape Floristic Region. The genus comprises 57 species and, with a number of closely related genera, it constitutes the ‘Metalasia clade’. A species‐level phylogenetic analysis is presented, based on DNA sequences from two nuclear (internal and external transcribed spacer: ITS, ETS) and two plastid (psbA‐trnH, trnL‐trnF) regions together with morphological data. Analyses combining molecular and morphological data attempt not only to resolve species interrelationships, but also to detect patterns in character evolution. Phylogenetic analyses corroborate our earlier study and demonstrate that Metalasia is formed of two equally sized, well‐supported sister groups, one of which is characterized by papillose cypselas. The results differ greatly from earlier hypotheses based on morphology alone, as few morphological characters support the phylogenetic patterns obtained. The two clades of Metalasia do, however, appear to differ in distribution, corresponding to the different rainfall regimes of South Africa. Analyses show a few taxa to be problematic; one example is the widely distributed M. densa which appears to be an intricate species complex. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174 , 173–198.  相似文献   

11.
Generic boundaries among the genera Cheilosporum, Haliptilon, and Jania—currently referred to the tribe Janieae (Corallinaceae, Corallinales, Rhodophyta)—were reassessed. Phylogenetic relationships among 42 corallinoidean taxa were determined based on 26 anatomical characters and nuclear SSU rDNA sequence data for 11 species (with two duplicate plants) referred to the tribe Corallineae and 15 species referred to the tribe Janieae (two species of Cheilosporum, seven of Haliptilon, and six of Jania, with five duplicate plants). Results from our approach were consistent with the hypothesis that the tribe Janieae is monophyletic. Our data indicate, however, that Jania and Haliptilon as currently delimited are not monophyletic, and that Cheilosporum should not be recognized as an independent genus within the Janieae. Our data resolved two well‐supported biogeographic clades for the included Janieae, an Indian‐Pacific clade and a temperate North Atlantic clade. Among anatomical characters, reproductive structures reflected the evolution of the Janieae. Based on our results, three genera, Cheilosporum, Haliptilon, and Jania, should be merged into a single genus, with Jania having nomenclatural priority. We therefore propose new combinations where necessary of some species previously included in Cheilosporum and Haliptilon.  相似文献   

12.
Major aspects of lorisid phylogeny and systematics remain unresolved, despite several studies (involving morphology, histology, karyology, immunology, and DNA sequencing) aimed at elucidating them. Our study is the first to investigate the evolution of this enigmatic group using molecular and morphological data for all four well-established genera: Arctocebus, Loris, Nycticebus, and Perodicticus. Data sets consisting of 386 bp of 12S rRNA, 535 bp of 16S rRNA, and 36 craniodental characters were analyzed separately and in combination, using maximum parsimony and maximum likelihood. Outgroups, consisting of two galagid taxa (Otolemur and Galagoides) and a lemuroid (Microcebus), were also varied. The morphological data set yielded a paraphyletic lorisid clade with the robust Nycticebus and Perodicticus grouped as sister taxa, and the galagids allied with Arctocebus. All molecular analyses maximum parsimony (MP) or maximum likelihood (ML) which included Microcebus as an outgroup rendered a paraphyletic lorisid clade, with one exception: the 12S + 16S data set analyzed with ML. The position of the galagids in these paraphyletic topologies was inconsistent, however, and bootstrap values were low. Exclusion of Microcebus generated a monophyletic Lorisidae with Asian and African subclades; bootstrap values for all three clades in the total evidence tree were over 90%. We estimated mean genetic distances for lemuroids vs. lorisoids, lorisids vs. galagids, and Asian vs. African lorisids as a guide to relative divergence times. We present information regarding a temporary land bridge that linked the two now widely separated regions inhabited by lorisids that may explain their distribution. Finally, we make taxonomic recommendations based on our results.  相似文献   

13.
The present study, based on sequences of cpDNA (trnL-F & psbA-trnH) and nrDNA (ITS) and morphology, examined the evolutionary relationships in Blumea and its position among related genera. The results confirmed that the closest relatives of Blumea are Caesulia, Duhaldea and Pentanema p.p., and showed that the monotypic genera Blumeopsis and Merrittia are nested within Blumea. In Blumea s.l., two major, well-supported clades were recognised and a single species, the widespread Blumea balsamifera, that could not be placed with certainty relative to the two main clades. The two main clades differ in habit, ecology and distribution. The Blumea densiflora clade contains shrubs and subshrubs of evergreen forests, distributed from continental Asia to New Guinea and Polynesia, whereas the Blumea lacera clade is a widespread paleotropical group that comprises mostly annual, weedy herbs of open forests and fields.  相似文献   

14.
Six species from the species-rich taxon Tisbe (Copepoda, Harpacticoida) were selected that could be reared in the laboratory as mass cultures. Phylogenetic relationships among these species were assessed by morphological studies of adults and larvae, DNA restriction site polymorphisms, allozymic, immunological distance, and lipid composition. Limits of scope and practicability of these analyses became apparent, as well as their potential and importance for future work in zoological systematics.  相似文献   

15.
Phylogenetic relationships in a group of 21 African rodent species designated as the Praomys group (Murinae) were investigated using morphological characters and sequence data from the complete mitochondrial cytochrome b gene and nuclear IRBP gene fragment (840bp). The molecular results confirm the monophyly of the Praomys group, including the species Malacomys verschureni, while the other Malacomys species appear very divergent. The basal relationships within the Praomys group are poorly resolved, suggesting a rapid radiation at about 7-9 million years ago based on genetic divergence rates calibrated from the fossil record. Discrepancies between molecular and morphological results probably reflect of numerous convergences as well as variations in the rates of morphological evolution among lineages. Reconstructions of the ancestral character states suggest a savannah origin for the Praomys group, along with some morphological traits conserved by stasis in savannah taxa. At the same time, forest taxa seem to be characterized by an accelerated morphological evolution, with acquisition of convergent adaptive characters.  相似文献   

16.
The land snail genus Mandarina has undergone extensive radiation within the Bonin Islands in the west Pacific. The preferred above-ground vegetation heights of sympatric species were clearly different. They separated into arboreal, semi-arboreal, exposed ground and sheltered ground ecotypes. Shells of species with different ecotypes differ markedly, but shells of species with the same ecotype are very similar to each other. Shell morphologies of some phylogenetically distantly related species with the same ecotype were indistinguishable. Character evolution estimated parsimoniously using a phylogenetic tree suggests that the speciation among sympatric species is accompanied by ecological and morphological diversification. In addition, species coexistence of Mandarina is related to niche differentiation. The above findings suggest that ecological interactions among species contribute to the ecological and morphological diversification and radiation of these land snails in this depauperate environment.  相似文献   

17.
The endemic land snail species Mandarina hahajimana has undergone extensive habitat and morphological diversification within the Hahajima islands in the Bonin archipelago. This species has diversified into populations with ground, arboreal and semi-arboreal life histories. In addition, arboreal populations and semi-arboreal populations show diversification in preferences of species and positions of the tree on which they are found. Shell morphologies of M. hahajimana exhibit remarkable geographical variation, and they have a clear relationship with their life histories. The morphological variation of M. hahajimana results from adaptation to different lifestyles. The habitats of these populations influence the relationships with other species of Mandarina coexisting with M. hahajimana. This suggests that the morphological and ecological divergence within M. hahajimana has been induced by competitive interaction with other species of Mandarina. Character displacement may have played an important role in promoting adaptive radiation of Mandarina in the Bonin Islands.  相似文献   

18.
To investigate the phylogenetic and phylogeographical relationships of arvicolines, we use several Western European ground voles. More particularly, our study is focused on Microtus ( Terricola ) savii and M. ( T. ) pyrenaicus . These two allopatric species are usually considered as having originated from the same ancestor, possibly M . ( T. ) mariaclaudiae . We propose molecular and morphological approaches: nucleotidic data from the mitochondrial cytochrome b and 12S rRNA genes and global morphological analyses from the first lower molar. Four other Terricola species ( multiplex , lusitanicus , duodecimcostatus , subterraneus ) were added to the data set for both analyses, and two other vole species ( Clethrionomys glareolus and Chionomys nivalis ) as outgroup to the molecular analysis, and five fossil populations to the morphological one. Palaeontological data are also widely taken into account. Both molecular and morphological analyses indicate that intra- Terricola relationships reflect the present-day geographical distribution of our data set species. Our results show that M. ( T. ) savii and M. ( T. ) pyrenaicus are from separate speciation events leading to two different biogeographical groups, respectively the Alpine–Italian group and the French–Iberian group, the latter being much more homogeneous. These speciation events could be related to Quaternary climatic changes, which induced southward migration, leading first to M. ( T. ) savii and second to M. ( T. ) pyrenaicus . The classical hypothesis of a geographical speciation for these two taxa from M. ( T. ) mariaclaudiae is invalid. However, the morphological data suggest a potential phylogenetic relationship between M. ( T. ) mariaclaudiae (ancestor) and M. ( T. ) pyrenaicus (descendant).  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 309–323.  相似文献   

19.
Many arctic‐alpine plant genera have undergone speciation during the Quaternary. The bases for these radiations have been ascribed to geographic isolation, abiotic and biotic differences between populations, and/or hybridization and polyploidization. The Cordilleran Campanula L. (Campanulaceae Juss.), a monophyletic clade of mostly endemic arctic‐alpine taxa from western North America, experienced a recent and rapid radiation. We set out to unravel the factors that likely influenced speciation in this group. To do so, we integrated environmental, genetic, and morphological datasets, tested biogeographic hypotheses, and analyzed the potential consequences of the various factors on the evolutionary history of the clade. We created paleodistribution models to identify potential Pleistocene refugia for the clade and estimated niche space for individual taxa using geographic and climatic data. Using 11 nuclear loci, we reconstructed a species tree and tested biogeographic hypotheses derived from the paleodistribution models. Finally, we tested 28 morphological characters, including floral, vegetative, and seed characteristics, for their capacity to differentiate taxa. Our results show that the combined effect of Quaternary climatic variation, isolation among differing environments in the mountains in western North America, and biotic factors influencing floral morphology contributed to speciation in this group during the mid‐Pleistocene. Furthermore, our biogeographic analyses uncovered asynchronous consequences of interglacial and glacial periods for the timing of refugial isolation within the southern and northwestern mountains, respectively. These findings have broad implications for understanding the processes promoting speciation in arctic‐alpine plants and the rise of numerous endemic taxa across the region.  相似文献   

20.
The gadoid fishes Theragra finnmarchica from the coast of northern Norway and Theragra chalcogramma from the north‐east Pacific could not be taxonomically discriminated by sequencing the mitochondrial cytochrome c oxidase I (COI) gene. However, the taxa differed in 10 of 42 non‐osteological and in four of 17 osteological characters. Ontogenetic changes were found for 16 of the examined non‐osteological characters. Five taxon‐specific characters, unaffected by ontogenetic scaling, were examined by discriminant analysis. A 100% correct classification was obtained from a discriminant function based on number of pyloric caeca and number of gill rakers on the upper part of the gill arch. However, all examined characters overlapped between the two taxa, except the number of pyloric caeca. On the basis of their genetic similarity and slight morphological differences, T. finnmarchica should be considered a junior synonym of T. chalcogramma.  相似文献   

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