Showing papers on "Genus published in 2008"

Phylogenetic heterogeneity of the genus Bacillus revealed by comparative analysis of small-subunit-ribosomal RNA sequences

Abstract: The small-subunit rRNA sequences of 51 species of Bacillus were determined by reverse transcription to elucidate the phylogenetic structure of the genus. Comparative analysis of the sequence data revealed five phylogenetically distinct clusters. Group 1 (Bacillus sensu stricto) included B. subtilis the type species of the genus and 27 other species. Group 2 consisted of B. sphaericus and five other bacilli and Sporosarcina ureae clustered within the confines of this group. Group 3 consisted of a phylogenetically coherent group of 10 species whereas groups 4 and 5 comprised two and three species respectively. It is evident that the genus Bacillus in genetically extremely heterogeneous and requires extensive taxonomic revision. The rRNA structures defined in the present study will provide a firm basis for the division of Bacillus into several phylogenetically distinct genera.

DNA barcodes and cryptic species of skipper butterflies in the genus Perichares in Area de Conservación Guanacaste, Costa Rica

Abstract: DNA barcodes can be used to identify cryptic species of skipper butterflies previously detected by classic taxonomic methods and to provide first clues to the existence of yet other cryptic species. A striking case is the common geographically and ecologically widespread neotropical skipper butterfly Perichares philetes (Lepidoptera, Hesperiidae), described in 1775, which barcoding splits into a complex of four species in Area de Conservacion Guanacaste (ACG) in northwestern Costa Rica. Three of the species are new, and all four are described. Caterpillars, pupae, and foodplants offer better distinguishing characters than do adults, whose differences are mostly average, subtle, and blurred by intraspecific variation. The caterpillars of two species are generalist grass-eaters; of the other two, specialist palm-eaters, each of which feeds on different genera. But all of these cryptic species are more specialized in their diet than was the morphospecies that held them. The four ACG taxa discovered to date belong to a panneotropical complex of at least eight species. This complex likely includes still more species, whose exposure may require barcoding. Barcoding ACG hesperiid morphospecies has increased their number by nearly 10%, an unexpectedly high figure for such relatively well known insects.

Biology and recent developments in the systematics of Phoma, a complex genus of major quarantine significance

Abstract: Species of the coelomycetous genus Phoma are ubiquitously present in the environment, and occupy numerous ecological niches. More than 220 species are currently recognised, but the actual number of taxa within this genus is probably much higher, as only a fraction of the thousands of species described in literature have been verified in vitro. For as long as the genus exists, identification has posed problems to taxonomists due to the asexual nature of most species, the high morphological variability in vivo, and the vague generic circumscription according to the Saccardoan system. In recent years the genus was revised in a series of papers by Gerhard Boerema and co-workers, using culturing techniques and morphological data. This resulted in an extensive handbook, the ?Phoma Identification Manual? which was published in 2004. The present review discusses the taxonomic revision of Phoma and its teleomorphs, with a special focus on its molecular biology and papers published in the post-Boerema era.

The genus Hyalomma Koch, 1844: v. re-evaluation of the taxonomic rank of taxa comprising the H. (Euhyalomma) marginatum koch complex of species (Acari: Ixodidae) with redescription of all parasitic stages and notes on biology

Abstract: The systematic morphology of species within the Hyalomma (Euhyalomma) marginatum Koch complex of ticks is illustrated and their relationships within this assemblage are discussed. Traditionally this group comprises the extremely polymorphic species Hyalomma (Euhyalomma) marginatum Koch, 1844 subdivided into four subspecies, namely H. (E.) marginatum marginatum Koch, 1844; H (E.) marginatum rufipes Koch, 1844; H (E.) marginatum isaaci Sharif, 1928 and/H. (E.) marginatum turanicum Pomerantzev, 1946. A fifth member of the association, namely H (E.) glabrum Delpy, 1949, has recently been re-instated as a full species. The taxonomic rank of the first mentioned four ticks is herein raised to species level. Details on the repositories of type specimens, synonyms, descriptions, variability, hosts, geographic distribution, and disease relationships of these four ticks are provided, and all their developmental stages are illustrated.

Phylogeny in cryptic weevils: molecules, morphology and new genera of western Palaearctic Cryptorhynchinae (Coleoptera : Curculionidae)

Abstract: A phylogeny is presented for the western Palaearctic representatives of the weevil subfamily Cryptorhynchinae using a combination of phenotypic and genotypic characters. This phylogeny is the first for the extremely species-rich Cryptorhynchinae to use molecular data (mitochondrial CO1 and 16S as well as nuclear ribosomal 28S). The results of this study show the need for molecular tools within this morphologically cryptic group of weevils and provide a scaffold based on which genus assignment can be tested. The present study mostly corroborates the current subdivision into genera (but many of the subgeneric groups are questioned). Three new genera are described: Montanacalles gen. nov. (type species: Kyklioacalles nevadaensis Stuben, 2001), Coloracalles gen. nov. (type species: Acalles humerosus Fairmaire, 1862) and Elliptacalles gen. nov. (type species: Acalles longus Desbrochers, 1892). Relevant external characters and the male genitalia of all discussed taxa are illustrated. Three species are transferred to different genera: Kyklioacalles aubei (Boheman, 1837) (formerly: Acalles), Ruteria major (Solari A. & F., 1907) and Ruteria minosi (Bahr & Bayer, 2005) (both formerly Echinodera).

Phylogeny of Miconia (Melastomataceae): Patterns of Stamen Diversification in a Megadiverse Neotropical Genus

Abstract: Phylogenetic relationships within Miconia and other genera in the Neotropical tribe Miconieae were investigated using a maximum parsimony analysis of nuclear internal transcribed spacer and ndhF nucleotide sequences. Included were all sections in Miconia (212 species, ∼20% of the genus) and 12 of the 15 remaining genera assigned to the tribe (an additional 239 species). Given the tribe’s reputation for problematic generic distinctions, it was not surprising that most traditionally recognized taxonomic groups—both genera and sections—were shown to be polyphyletic or paraphyletic. Nevertheless, Miconia is composed of several distinct monophyletic groups, with a large majority of the species belonging to only four clades. Some of these groups represent parts of sections proposed in the last revision of the genus, but most of the diversification seems to have occurred in geographical areas that are more restricted than would have been predicted by the distribution of these sections. Moreover, parallel evoluti...

Coleofasciculus gen. nov. (cyanobacteria): morphological and molecular criteria for revision of the genus microcoleus gomont(1).

Abstract: Species currently classified within the cyanobacterial genus Microcoleus were determined to fall into two distinct clades in a 16S rDNA phylogeny, one containing taxa within the Oscillatoriaceae, the other containing taxa within the Phormidiaceae. The two lineages were confirmed in an analysis of the 16S-23S internal transcribed spacer (ITS) region sequences and secondary structures. The type species for Microcoleus is M. vaginatus Gomont, and this taxon belongs in the Oscillatoriaceae. Consequently, Microcoleus taxa in the Phormidiaceae must be placed in separate genera, and we propose the new genus Coleofasciculus to contain marine taxa currently placed in Microcoleus. The type species for Coleofasciculus is the well-studied and widespread marine mat-forming species Microcoleus chthonoplastes (Mert.) Zanardini ex Gomont. Other characters separating the two families include type of cell division and thylakoid structure.

Evolutionary relationships in the showy mistletoe family (Loranthaceae).

Abstract: Loranthaceae (73 genera and ca. 900 species) comprise mostly aerial hemiparasitic plants. Three monotypic genera considered relicts are root parasites. The family is diverse in tropical areas, but representatives are also found in temperate habitats. Previous classifications were based on floral and inflorescence morphology, karyological information, and biogeography. The family has been divided into three tribes: Nuytsiae, Elytrantheae (subtribes Elytranthinae and Gaiadendrinae), and Lorantheae (subtribes Loranthinae and Psittacanthinae). Nuytsiae and Elytrantheae are characterized by a base chromosome number of x = 12, whereas subtribes Loranthinae (x = 9) and Psittacanthinae (x = 8) numbers are derived via aneuploid reduction. To elucidate the phylogeny of the family, we analyzed sequences from five genes (nuclear small and large subunit rDNA and the chloroplast genes rbcL, matK, and trnL-F) representing most genera using parsimony, likelihood, and Bayesian inference. The three root parasites, Nuytsia, Atkinsonia, and Gaiadendron, are supported as successive sister taxa to the remaining genera, resulting in a monophyletic group of aerial parasites. Three major clades are resolved each corresponding to a subtribe. However, two South American genera (Tristerix and Notanthera) and the New Zealand genus Tupeia, which were previously classified in subtribe Elytranthinae, are weakly supported as part of a clade representing the South American subtribe Psittacanthinae.

Taxonomic and ecologic problems in the genus Lepraria (Stereocaulaceae, lichenised Ascomycota)

Abstract: A comparative review of 58 Lepraria species and 2 varieties is provided together with species descriptions and a key. Lecanora leuckertiana is transferred to Lepraria. The following taxa are included: Lepraria achariana, L. adhaerens, L. alpina var. alpina, L. alpina var. zeorinica, L. atlantica, L. atrotomentosa, L. aurescens, L. bergensis, L. borealis, L. caesiella, L. caesioalba var. caesioalba, L. caesioalba var. groenlandica, L. celata, L. coriensis, L. crassissima, L. diffusa, L. eburnea, L. ecorticata, L. elobata, L. friabilis, L. gelida, L. goughensis, L. granulata, L. humida, L. impossibilis, L. incana, L. isidiata, L. jackii, L. lanata, L. lecanorica, L. leprolomopsis, L. leuckertiana, L. lobata, L. lobificans, L. membranacea, L. multiacida, L. neglecta, L. neojackii, L. nigrocincta, L. nivalis, L. normandinoides, L. nylanderiana, L. obtusatica, L. pallida, L. pulchra, L. rigidula, L. salazinica, L. santamonicae, L. santosii, L. sipmaniana, L. squamatica, L. straminea, L. sylvicola, L. texta, L. toensbergiana, L. toilenae, L. umbricola, L. usnica, L. vouauxii, L. xerophila. Additionally some previously published but unnamed taxa by different authors are discussed.

Relationships in the barley genus (Hordeum): an electrophoretic examination of proteins

Abstract: The relationships between all known Hordeum species except H. guatemalense were inferred from the electrophoresis of the six enzyme systems Got, 6-Pgd, Mdh, Idh, a-and B-amylases. A total of eleven loci were scored for in these systems. Maximum likelihood clusters and Wagner networks calculated from the electrophoretic data divided the genus into three groups, viz. the “H. vulgare group”, the “H. marinum group” and the “H. pubiflorum group”. Only one of these groups was recognized in the morphological sectioning of the genus. Most of the polyploid cytotypes in the genus seemed to have originated as alloploids. Phylogenetic links between diploid and polyploid taxa are suggested from the enzyme phenotypes. An evolutionary theory for the genus Hordeum is proposed, with two centres of differentiation, in South-West Asia and South America, respectively.

Importance of Leaf Epidermal Characters in the Asteraceae Family

Abstract: A comparative study of the leaf epidermis of twelve species in the Compositae (Asteraceae) family was undertaken in order to document characters that are important in the taxonomy of the family. It was observed that trichomes can be successfully used for the delimitation of genera within the family. Within each species however, there are varied assortment of trichomes with occasional transitions among them. Launaea taraxacifolia was unique in being the only species without any trichome. Stellate trichome type and K-shaped or tetraradiate trichomes were observed in Tridax procumbens only. The genus Vernonia can be delimited from the other genera by the possession of T - shaped trichomes which are absent in the other genera, while amoeboid-shaped trichomes can be found in the genus Chromolaena only. Within the same genus, the species can also be delimited on the basis of possession of unique trichome types, for example in the genera Vernonia and Emilia. Cuticular striations occur in only two species out of the twelve studied, on the abaxial surface of V. amygdalina and on both surfaces of Bidens pilosa. Four stomatal types were recorded for the family, anomocytic, brachyparacytic, anisocytic and diacytic. Stomatal type was observed to delimit not only at generic level, but also at specific or species level. Ageratum conyzoides and Synedrella nodiflora are the only two species with occasional diacytic stomatal types. Results of the statistical correlation analysis for stomatal size and stomatal index at the 0.05 and 0.01 levels revealed high positive correlation for species in the same tribe, as well as for species in different tribes affirming close interrelationship and overlap of the values of stomatal indices and sizes within the family. Foliar anatomical characters that justify the separation of Vernonia amygdalina and Vernonia cinerea into separate tribes are highlighted.

Assigning morphological variants of Fucus (Fucales, Phaeophyceae) in Canadian waters to recognized species using DNA barcoding

Abstract: The intertidal brown algal genus Fucus (Phaeophyceae) consists of individuals with a generally dichotomously branched habit Morphological variability within species, combined with morphological si

Phylogenetic Relationships and Taxonomic Status Of the Paleoendemic Fagaceae Of Western North America: Recognition Of A New Genus, Notholithocarpus

Abstract: We investigated the phylogenetic relationships and taxonomic status of the castaneoid component (Lithocarpus and Chrysolepis) of the family Fagaceae that is endemic to the California Floristic Province (CA-FP). Over 7800 basepairs of nuclear and chloroplast DNA were analyzed in 17 taxa representing the breadth of phylogenetic diversity in the family. The genus Lithocarpus, as currently defined, is clearly polyphyletic due to the inclusion of L. densiflorus. Here, we designate this taxon as a new genus, Notholithocarpus, which can be recognized morphologically by its relatively small, subprolate pollen. Notholithocarpus is more closely related to Quercus, Castanea, and Castanopsis; Chrysolepis was resolved as the sister group to Lithocarpus sensu stricto. These results indicate that Notholithocarpus does not possess true ‘flower cupules,’ which define Lithocarpus sensu stricto, but like the oaks, the single flower per cupule is derived through the abortion of lateral flowers within each cupule. Fu...

Adaptation in the genus phylloscopus

Abstract: SUMMARY The paper describes variation among species of the genus Phylloscopus in weight, relative wing-, tail-, tarsus-, and bill-length, tail/wing ratio and degree of roundness of the wing, wing formula, emargination, and plumage colour. This variation is compared with differences in niche preference within the genus, and relationships between niche, feeding strategies, and morphology are suggested. It is concluded that evolution within the genus has taken place mainly through the development of different feeding strategies, to suit the structural properties of different niches, without altering the range of size of the prey. The genus Sylvia is treated briefly in order to provide comparison, and other genera of Sylviinae are discussed where parallel adaptation seems likely.

A phylogenetic perspective on 160 years of troubled taxonomy of Niphargus (Crustacea: Amphipoda)

Abstract: Niphargus is the largest genus of freshwater amphipods. Its systematics from the species to the family level has always been problematic. This study is the first comprehensive phylogenetic treatment of the chiefly subterranean group in 160 years of its taxonomic history. It includes 103 niphargid species plus outgroups, representing about one-third of all nominal species. The samples originated mainly from type localities or adjacent sites and covered most of the morphological variability of the genus. Character sampling included nuclear 28S and mitochondrial 12S rDNA sequences, and 122 morphological characters. Quantitative morphological traits were coded using two alternative methods. The first one searches for gaps in the variability range of each character, while the second one uses absolute differences between the standardized raw data as weights. Different data sets yielded alternative topologies. All data support the monophyly of Niphargidae, while Niphargopsis— another niphargid genus — was consistently nested within Niphargus, loosing justification for its separate status. We predict a similar fate for all or most of the remaining six small niphargid genera, which were not yet scrutinized phylogenetically. Different topologies agreed in species composition of five large, well-supported clades, although the hierarchic relationships between them remain unresolved. These clades reject all previously proposed taxonomic subdivisions of Niphargus, implying a high degree of morphological homoplasy that renders any morphology-based groups questionable. The clade members are distributed within well-established zoogeographical regions that do not exceed 1300 km across the longest diagonal. These results provide a framework for future studies on niphargid systematics, the evolution of endemism and cryptic diversity in subterranean environments, the mechanisms leading to exceptional morphological heterogeneity, historical biogeography, and applied ecological issues.

Species-genus ratios reflect a global history of diversification and range expansion in marine bivalves

Abstract: The distribution of marine bivalve species among genera and higher taxa takes the form of the classic hollow curve, wherein few lineages are species rich and many are species poor. The distribution of species among genera (S/G ratio) varies with latitude, with temperate S/G9s falling within the null expectation, and tropical and polar S/G9s exceeding it. Here, we test several hypotheses for this polar overdominance in the species richness of small numbers of genera. We find a significant positive correlation between the latitudinal range of a genus and its species richness, both globally and within regions. Genus age and species richness are also positively related, but this relationship breaks down when the analysis is limited to genera endemic to climate zones or with narrow latitudinal ranges. The data suggest a link between speciation and range-expansion, with genera expanding out of the tropical latitudinal bins tending to speciate more prolifically, both globally and regionally. These genera contain more species within climate zones than taxa endemic to that zone. Range expansion thus appears to be fundamentally coupled with speciation, producing the skewed distribution of species among genera, both globally and regionally, whereas clade longevity is achieved through extinction—resistance conferred by broad geographical ranges.

Global diversity of water mites (Acari, Hydrachnidia; Arachnida) in freshwater

Abstract: The Hydrachnidia (water mites) represent the most important group of the Arachnida in fresh water. Over 6,000 species have been described worldwide, representing 57 families, 81 subfamilies and more than 400 genera. The article analyzes extant water mite diversity and biogeography. Data on distribution and species richness of water mites are substantial but still far from complete. Many parts of the world are poorly investigated, Oriental and Afrotropical regions in particular. Moreover, information among different freshwater habitats is unbalanced with springs and interstitial waters disproportionately unrepresented. Therefore, more than 10,000 species could be reasonably expected to occur in inland waters worldwide. Based on available information, the Palaearctic region represents one of the better investigated areas with the highest number of species recorded (1,642 species). More than 1,000 species have been recorded in each of the Neotropical (1,305 species) and Nearctic regions (1,025 species). Known species richness is lower in Afrotropical (787 species) and Australasian (694 species) regions, and lowest in the Oriental region (554 species). The total number of genera is not correlated with species richness and is distinctly higher in the Neotropical (164 genera); genus richness is similar in the Palaearctic, Nearctic and Australasian regions (128–131 genera) and is lower in the Afrotropical and Oriental regions with 110 and 94 genera, respectively. A mean number of about three genera per family occur in the Palaeartic, Nearctic and Oriental while an average of more than four genera characterizes the families of Australasian and Afrotropical regions and more than five genera those of the Neotropical. Australasian fauna is also characterized by the highest percentage of endemic genera (62%), followed by Neotropical (50.6%) and Afrotropical (47.2%) regions. Lower values are recorded for the Palaearctic (26.9%), Oriental (24.4%) and Nearctic (21.4%). The Palaearctic and Nearctic have the highest faunistic similarity, some minor affinities are also evident for the generic diversification of Holarctic and Oriental families. The faunas of Southern Hemisphere bioregions are more distinct and characterized by the presence of ancient Gondwanan clades with a regional diversification particularly evident in the Neotropics and Australasia. This scenario of water mite diversity and distribution reflect the basic vicariance pattern, isolation, phylogenetic diversification, recent climatic vicissitudes and episodes of dispersal between adjacent land masses together with extant ecological factors can be evoked to explain distribution patterns at a global scale.

DNA barcoding of a large genus, Aspalathus L. (Fabaceae)

Abstract: The DNA barcode potential of three regions (the nuclear ribosomal ITS and the plastid psbA-trnH and trnT-trnL intergenic spacers) was investigated for the plant genus Aspalathus L. (Fabaceac: Crotalarieae). Aspalathus is a large genus (278 species) that revealed low levels of DNA variation in phylogenetic studies. In a 51-species dataset for the psbA-trnH and ITS regions, 45%, and 16% of sequences respectively were identical to the sequence of at least one other species, with two species undiscriminated even when the two regions were combined. In contrast, trnT-trnL, discriminated between all species in this dataset. In a larger ITS and trnT-trnL dataset. including a further 82 species. 7 species in five pairwise comparisons remained Undiscriminated when the two regions were combined. Four of the five pairs of species not discriminated by sequence data were readily distinguished using a combination of qualitative and quantitative morphological data. The difficulty of barcoding in this group is increased by the presence of intraspecific variation in all three regions studied. In the case of psbA-trnH, three intraspecific samples had a sequence identical to at least one other species. Overall, psbA-trnH. currently a candidate for plant barcoding, was the least discriminatory region in our study.