Abundance and characteristics of Pisolithus ectomycorrhizas in New Zealand geothermal areas

Pisolithus is restricted in New Zealand to geothermal areas where it associates with Kunzea ericoides var. microflora (prostrate kanuka) and occasionally Leptospermum scoparium. Here we describe for the first time the ectomycorrhizal morphotypes of three New Zealand Pisolithus species and report the frequency and abundance of these morphotypes against other mycorrhizal fungi associated with these hosts in New Zealand geothermal areas. The three Pisolithus species form typical ectomycorrhizal associations with Kunzea ericoides var. microflora, and one also was observed forming typical ectomycorrhizal associations with Leptospermum scoparium. Although the morphotypes from the three Pisolithus species share many morphological and anatomical characteristics, they vary with regard to the abundance of rhizomorphs. The common occurrence of Pisolithus fruiting bodies at the geothermal sites was matched by frequent and abundant Pisolithus ectomycorrhizas. Pisolithus ectomycorrhizas were frequent (100% of soil cores) and abundant (between 55 and 88% of ectomycorrhizal tips) associates of prostrate kanuka in hot (50 C at 8 cm depth), highly acidic and N depleted soils. The levels of arbuscular mycorrhizal colonization of prostrate kanuka were lower than on K. ericoides and L. scoparium on cooler soils. The stressful conditions where prostrate kanuka dominates probably favor Pisolithus over the mycorrhizal fungi occurring in cooler geothermal areas. Questions about how several genetically similar Pisolithus species co-occur on prostrate kanuka in geothermal areas without mutual competitive exclusion are discussed.     

DNA-based taxonomy for associating adults and larvae in multi-species assemblages of chafers (Coleoptera: Scarabaeidae)

DNA sequences provide a universal character system in taxonomy for associating all developmental stages of organisms, but ambiguity arises due to genetic variation within species. The problem is compounded where target groups are less well studied or incompletely represented in DNA databases. Here we investigate the utility of DNA for larval-adult species associations within chafer (Coleoptera: Scarabaeidae) communities from four sites in the tropical lowlands of Nepal. We sequenced ca. 1600 bp of mitochondrial cox1 and rrnL and 700 bp of nuclear 28S rRNA from 250 larval and adult specimens. Individuals were grouped into putative species using statistical parsimony analysis and population aggregation analysis (PAA), whereby specimens from each locality were grouped according to the presence of diagnostic nucleotides. In addition, species membership was determined based on shifts in branching rates on clock-constrained trees to detect the putative transition from speciation to population coalescence patterns. Using these two methods we delineated between 48 and 56 groups, of which 16-20 were composed of larval and adult individuals. Nuclear and mtDNA-based groups were highly congruent; variation of 28S rRNA within groups was very low, while one widespread 28S rRNA genotype was universally found in a paraphyletic group of five mtDNA clusters. Linnean names could be assigned to 19 groups, and hence between 86.1% and 92.7% of larval specimens could be associated to species by their membership in clearly delineated groups that contained fully identified adults. The remaining larvae were delineated as five species, four of which could be assigned to Anomala or Adoretus based on their phylogenetic position. We conclude that the sequence variation was highly structured in this complex assemblage of chafers and that any given individual (larva or adult) can be readily associated with a particular DNA group using the criterion of diagnos ability. The association of different developmental stages therefore becomes a matter of determining the extent of the DNA-based groups, rather than matching of sequences from adult and larval individuals. This indicates the need for a purely sequence-based taxonomic system when associating different life stages via DNA.     

贵州蚋属一新种(双翅目：蚋科)

记述采自贵州雷公山的蚋属一新种, 显著蚋Simulium (Simulium) prominentum, 新种。根据其蛹和幼虫的特征显著而命名, 对其幼期形态进行描述并与其近缘种作分类讨论。     

Genetic differentiation in relation to marine landscape in a broadcast-spawning bivalve mollusc (Placopecten magellanicus)

Marine bivalves are sessile or sedentary as adults but have planktonic larvae which can potentially disperse over large distances. Consequently larval transport is expected to play a prominent role in facilitating gene flow and determining population structure. The sea scallop (Placopecten magellanicus) is a dioecious species with high fecundity, broadcast spawning and a c. 30-day planktonic larval stage, yet it forms discrete populations or 'beds' which have significantly different dynamics and characteristics. We analysed variation at six microsatellite loci in 12 locations throughout the geographic range of the species from Newfoundland, Canada, to New Jersey, USA. Significant differentiation was present and the maximum pairwise theta value, between one of the Newfoundland samples in the north and a sample from the southern portion of the range, was high at 0.061. Other proximate pairs of samples had no detectable genetic differentiation. Mantel tests indicated a significant isolation by distance, but only when one of the populations was excluded. A landscape genetic approach was used to detect areas of low gene flow using a joint analysis of spatial and genetic information. The two major putative barriers inferred by Monmonier's algorithm were then used to define regions for an analysis of molecular variance (amova). That analysis showed a significant but low percentage (1.2%) of the variation to be partitioned among regions, negligible variation among populations within regions, and the majority of the variance distributed between individuals within populations. Prominent currents were concordant with the demarcation of the regions, while a novel approach of using particle tracking software to mimic scallop larval dispersal was employed to interpret within-region genetic patterns.     

Morphological variability and genetic identity in Rhinoestrus spp. causing horse nasal myiasis

Larvae of Rhinoestrus purpureus (Brauer) and Rhinoestrus usbekistanicus Gan (Diptera: Oestridae) cause nasal myiases of equids. During a recent epidemiological survey in southern Italy some morphological and taxonomical doubts arose concerning the identification of Rhinoestrus third stage larvae on the basis of the features of the posterior spiracles and the distribution of dorsal spines on the third segment. Four different morphotypes were retrieved: R. usbekistanicus-like, R. purpureus-like and two morphotypes with shared features. The genes encoding for the mitochondrial cytochrome oxidase I (COI) and for the ribosomal subunits 16S and 28S of the four morphotypes of Rhinoestrus were investigated to determine whether they belonged to a single taxon or they displayed genetic differences indicative of more than one species. The three genes showed a very low level of sequence variation (COI 0-0.43%, 16S 0-1.45%, 28S 0-0.23%) falling within the intraspecific ranges previously described for Oestridae species. Finally, the peritreme features and the spinulation of the third segment of the four morphotypes examined could not be used to differentiate the two species.     

云南蚋属一新种：双翅目：蚋科

本文描述在云南省采获的谭氏蚋新种Simulium tanae sp.nov.各期虫态标本。新种幼虫的亚頦与头囊腹面缺刻,蛹鳃呼吸丝组成与苏联蚋科志中的淡额蚋Simulium nlleri Friederichs和河蚋Simulium zalertum Edw.近似;茧的形态又近似于二齿吉蚋Gnus bidentatum Shirkl,但是雄的生殖器和雌的口器形态特征与上述种类差别较明显,因此鉴定为新种。新种模式标本保存于云南省流行病研究所。     

Electrophoretic examination of the population structure of brown trout, Salmo trutta L., from the Lough Neagh catchment, Northern Ireland

Samples of brown trout, Salmo trutia L., from 34 locations throughout the Lough Neagh system in north-east Ireland were electrophoretically examined for genetic variation at 28 enzyme loci. Patterns of allelic variation at 12 polymorphic loci indicated the existence of genetic differentiation within as well as among several river systems, suggesting the existence of multiple brown trout populations. Significant gene frequency differences were detected over distances as little as 3 km, demonstrating the propensity of this species for microgeographic genetic differentiation. This was confirmed by a hierarchical analysis of genetic variance, some 35% of among-sample variance being distributed within tributaries. Within Lough Neagh itself significant genetic differentiation was detected between two morphotypes (dollaghan and salmon-trout) and for one of these (dollaghan) among samples from different years and from different areas of the lough. This suggests the existence of genetically differentiated subpopulations of originating from separate river catchments.     

Morphological and genetic evidence supports the existence of two species in the genus Ophelia (Annelida, Polychaeta) from the Western Mediterranean

About 900 individuals of the intertidal polychaete Ophelia cf. bicornis were collected at four sandy beaches in Corsica, ten in Sardinia and one in Tuscany (Western Mediterranean). They were analysed morphologically and genetically to clarify the taxonomic status of the littoral species of Ophelia in the study area and to assess the population genetic structuring. Two morphotypes were distinguished on the basis of the number of nephridiopore pairs (five or six). Genetic distances, F -statistics and analysis of molecular variance based on eight allozyme genetic markers were consistent in showing the two morphotypes to separate at species level. Thus, the two morphotypes which most authors have included in O. bicornis s.l. are not one morphologically variable taxon, but instead constitute two valid species, namely O. bicornis Savigny, 1818, with six pairs of nephridiopores, and O. barquii Fauvel, 1927, with five pairs of nephridiopores. Mechanisms of ecological speciation in a background of gene flow can be taken into account to explain the origin of the two species. Moderate genetic differentiation was found among populations within each species, suggesting that dispersal may not be effective over large distances, or that local selection plays an important role in population differentiation.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 83 , 101–113.     

Germination Ecophysiology of the Mesic Deciduous Forest Herb Polemonium reptans var. reptans (Polemoniaceae)

Abstract Seeds of Polemonium reptans var. reptans , a perennial herb of mesic deciduous forests in eastern North America, mature in late May-early June, and a high percentage of them are dormant. Seeds afterripened (came out of dormancy) during summer when kept in a nylon bag under leaves in a nonheated greenhouse or on wet soil in a 30/15°C incubator. The optimum temperature for germination of nondormant seeds was a simulated October (20/10°C) regime. In germination phenology studies in the nonheated greenhouse, 20–30% of the seeds that eventually germinated did so in October, and the remainder germinated the following February and March. Since low (5°C) winter temperatures promote some afterripening (ca. 50%) and do not cause nondormant seeds to re-enter dormancy, seeds that fail to germinate in autumn may germinate in spring. Thus, the taxon has very little potential to form a persistent seed bank. The large spatulate embryos and ability of seeds to afterripen at high temperatures means that seeds of P. reptans var. reptans have nondeep physiological dormancy, unlike many herbaceous woodland species, which have morphophysiological dormancy.     

贵州蚋属一新种 (双翅目：蚋科)

 记述采自贵州雷公山的蚋属一新种, 显著蚋Simulium (Simulium) prominentum, 新种 。根据其蛹和幼虫的特征显著而命名, 对其幼期形态进行描述并与其近缘种作分类讨论。     

New Material of Carex Subgenus Vignea from China

In addition, two new sections, Echinochlomorphae Y. L. Chang and Thomsonianae Y. L. Chang, two new combinations, C. duriuscula subsp. rigescens (Franch.) S. Y. Liang et Y. C. Tang (=C. stenophylla var. rigescens Franch.) and C. rochebrunii Franch. Subsp. reptans (Franch.) S. Y. Liang et Y. C. Tang (=C. remotae L. var. reptans Franch.) are made, and C. stenophylloides V. Krecz. is reduced to C. duriuscula subsp. stenophylloides (V. Krecz.) S. Y. Liang et Y. C.Tang.     

var1 Gene on the mitochondrial genome of Torulopsis glabrata

We have cloned and sequenced a region of the Torulopsis glabrata mitochondrial genome homologous to the Saccharomyces cerevisiae var1 gene (var1Sc). An open reading frame that could encode a protein of 339 amino acids was found with 72.7% amino acid and 85.3% nucleotide sequence homology to the S. cerevisiae var1 gene. The T. glabrata gene (var1Tg) is transcribed yielding two stable RNAs, a more abundant 13.5 S RNA and a less abundant 18 S species. We have also identified a candidate for a T. glabrata var1 protein among mitochondrial translation products labeled in isolated mitochondria. The var1Tg gene is even more A + T-rich (93%) than var1Sc (89.6%) and has conserved the strong codon bias of var1Sc. Major differences between the two sequences were found. Significant among these are that no GC clusters are found in var1Tg and the sequences surrounding each of the sites where known polymorphisms exist in var1Sc have deletions at the corresponding sites in var1Tg. These data are discussed with respect to possible origins of these var1 genes and translocation of GC clusters in S. cerevisiae mitochondrial DNA.     

Molecular phylogeny of the Sphaerophorus globosus species complex

The Sphaerophorus globosus complex (Lecanorales, lichenized Ascomycota) shows a large morphological variation, and three relatively distinct morphotypes can be distinguished in parts of the distribution area. Here, we utilize a multigene‐based maximum‐parsimony approach (nITS+ LSU rDNA, mtSSU rDNA, β‐tubulin, and actin) to investigate whether these morphotypes constitute distinct species. The results show that there are at least two well‐supported monophyletic groups that we interpret as phylogenetic species within the S. globosus complex. These species do not completely correspond to the predefined morphotypes. One group, an apparently undescribed species, contains noncoralloid specimens from the North American Pacific Northwest. The other group, S. globosus, consists of two well‐supported monophyletic groups: one contains coralloid epiphytic specimens from the North American Pacific Northwest that are morphologically indistinguishable from epiphytic specimens from Europe and are presently interpreted as belonging to the same species and the other is morphologically variable and contains terrestrial specimens from Europe, North America, and southernmost South America and coralloid epiphytic and epilithic specimens from Europe. The results suggest that the population in southernmost South America originated by long‐distance dispersal from arctic populations in the Northern Hemisphere.     

A reliable DNA barcode reference library for the identification of the North European shelf fish fauna

Valid fish species identification is an essential step both for fundamental science and fisheries management. The traditional identification is mainly based on external morphological diagnostic characters, leading to inconsistent results in many cases. Here, we provide a sequence reference library based on mitochondrial cytochrome c oxidase subunit I (COI) for a valid identification of 93 North Atlantic fish species originating from the North Sea and adjacent waters, including many commercially exploited species. Neighbour‐joining analysis based on K2P genetic distances formed nonoverlapping clusters for all species with a ≥99% bootstrap support each. Identification was successful for 100% of the species as the minimum genetic distance to the nearest neighbour always exceeded the maximum intraspecific distance. A barcoding gap was apparent for the whole data set. Within‐species distances ranged from 0 to 2.35%, while interspecific distances varied between 3.15 and 28.09%. Distances between congeners were on average 51‐fold higher than those within species. The validation of the sequence library by applying BOLDs barcode index number (BIN) analysis tool and a ranking system demonstrated high taxonomic reliability of the DNA barcodes for 85% of the investigated fish species. Thus, the sequence library presented here can be confidently used as a benchmark for identification of at least two‐thirds of the typical fish species recorded for the North Sea.     

Description and genetic characterisation of Hysterothylacium (Nematoda: Raphidascarididae) larvae parasitic in Australian marine fishes

Nematodes belonging to the genus Hysterothylacium (family Raphidascarididae) infect various species of marine fish in both the larval and adult stages. Humans can be accidentally infected upon eating infected seafood. In spite of their importance, relatively little is known of their occurrence and systematics in Australia. An examination of various species of marine teleosts in Australian waters revealed a high prevalence of Hysterothylacium larval types. In the present study, seven previously undescribed Hysterothylacium larval morphotypes (V to VII and IX to XII) were discovered. In total we found 10 different morphotypes and we genetically characterised nine morphotypes identified. A morphological dichotomous identification key has been established to differentiate these morphotypes. Since some larvae of Hysterothylacium from marine fishes cannot be differentiated morphologically from other nematode larvae, such as Paraheterotyphlum, Heterotyphlum, Iheringascaris and Lapetascaris, the first and second internal transcribed spacers (ITS-1 and ITS-2) of nuclear ribosomal DNA (rDNA) of these larvae were characterised to confirm their taxonomic status. This genetic characterisation implied that some distinct morphotypes belong to different developmental stages of the same species. In addition, it revealed that some morphotypes can comprise distinct genotypes. No match was found between ITS-1 and ITS-2 sequences obtained from larvae in the present study and those from adults available in the GenBank, highlighting the lack of knowledge on occurrence of adult nematodes infecting Australian fish.     

Population genetic structure of a widespread coniferous tree, Taxodium distichum [L.] Rich. (Cupressaceae), in the Mississippi River Alluvial Valley and Florida

Studies of genetic variation can elucidate the structure of present and past populations as well as the genetic basis of the phenotypic variability of species. Taxodium distichum is a coniferous tree dominant in lowland river flood plains and swamps of the southeastern USA which exhibits morphological variability and adaption to stressful habitats. This study provides a survey of the Mississippi River Alluvial Valley (MAV) and Florida to elucidate their population structure and the extent of genetic differentiation between the two regions and sympatric varieties, including bald cypress (var. distichum) and pond cypress (var. imbricatum). We determined the genotypes of 12 simple sequence repeat loci totaling 444 adult individuals from 18 natural populations. Bayesian clustering analysis revealed high levels of differentiation between the MAV and the Florida regions. Within the MAV region, there was a significant correlation between genetic and geographical distances. In addition, we found that there was almost no genetic differentiation between the varieties. Most genetic variation was found within individuals (76.73?%), 1.67?% among individuals within population, 15.36?% among populations within the regions, and 9.23?% between regions within the variety. Our results suggest that (1) the populations of the MAV and the Florida regions are divided into two major genetic groups, which might originate from different glacial refugia, and (2) the patterns of genetic differentiation and phenotypic differentiation were not parallel in this species.     

Phenotypic Variation among and within Three Peppers Species (<i>Capsicum</i>) from Mexico

The phenotypic variation and its distribution among species, morphotypes, and among and within populations was estimated in 71 populations pertaining to 15 morphotypes of three domesticated species of Capsicum from Mexico. Collections were made in the states of Sinaloa, Nayarit, Oaxaca, Tabasco, and Yucatán in two agroecosystems: Backyard-garden and monoculture. Fifteen phenotypic characteristics were analyzed through one-way variance analysis and multivariate analyses of principal components analysis (PCA) and hierarchical clustering using Ward’s method. The study was performed in a uniform greenhouse experiment. A high variation was found among and within populations in all the measured characteristics. Of the total variation, 13.0% was distributed among species, 27.9% among morphotypes, 8.1% among populations, and 51.0% within populations. Because plants grew in a uniform environment, these results indicate that the differences observed among and within species, morphotypes, and populations have a genetic basis. Univariate and multivariate analyses clearly differentiated morphotypes, suggesting that the category of morphotypes must be used to nominate the infraspecific variation in the domesticated Capsicum. The principal components analysis identified a total of 15 principal components that contributed to explain the total variation. The first two components explained 59.64% of the total variation and seven components explained more than 90% of the total variation. Among the measured characteristics, number of seed per fruit, weight of the fruit, width of the fruit, length of the fruit, stem diameter, days to flowering, and height of the plant contributed to component 1 variation, whereas width of the leaf, length of the leaf, and number of locules, number of fruits and number of seeds per plant contributed to component 2. The hierarchical clustering separated the populations and the morphotypes in two large different groups. One group consisted of populations collected in monoculture conditions and the other group corresponded to population collected from backyard-garden conditions. The monoculture populations were characterized mainly by their longer, wider, and higher weight fruits, plants were of less height, had smaller stem diameters, and lower number of fruits than the populations collected from the backyard-garden conditions. The backyard-garden populations of the Capsicum annuum and Capsicum frutescens species, considered wild or semi-domesticated, constituted a non-differentiated phenotypic group that does not allow dividing them in different species.     

Genetic differentiation of starling (Sturnus vulgaris: Aves) populations in New Zealand and Great Britain

Several hundred starlings (Sturnus vulgaris) were introduced to New Zealand from Great Britain during1860–1880. Allozymic variation at 24 loci was analysed in winter populations sampled at six localities in each country. New Zealand samples had fewer alleles per locus but the same mean heterozygosity (3% per locus) and proportion of polymorphic loci as did British samples. Winter populations in Britain contain European migrants and were genetically homogeneous. Paradoxically, genetic distances among derived New Zealand populations, and between New Zealand and Great Britain were much greater, similar in magnitude to those observed among allopatric populations in other avian species. The geographical pattern of genetic variation in New Zealand suggests that reproductive isolation of populations and random drift have contributed to the development of population differentiation.