中国宽头秆蝇属二新种：双翅目：秆蝇科

中国宽头秆蝇属二新种（双翅目：秆蝇科）杨集昆,杨定（北京农业大学植物保护系,北京市１０００９４）关键词双翅目,秆蝇科,宽头秆蝇属,新种双翅目秆蝇科（ＣｈｌｏｒｏＰｉｄａ）的宽头秆蝇属（Ｐｌａｔｙｃｅｐｈａｌ）种数不多,包括一些体型较大的秆蝇。我国仅东...     

甘肃南部头蝇科一新种（双翅目）

本文描述了采自甘肃文县头蝇科,肾头蝇属（ＮｅｐｈｒｏｃｅｒｕｓＺｅｔ．）一新种,其主要特征：中胸背板两侧各具一耳状薄片突起物,后足转节后腹面具５枚短且粗的黑刺,第１腹节背板具“Ｙ”字形斑,第２及第３腹节背板具倒吊钟状斑     

内蒙古头蝇三新种及—中国新记录种(双翅目:头蝇科)

双翅目(Diptera)芒角亚目(Aristocera)无缝组(Aschiza)的头蝇科(Pipunculidae)昆虫多为小型暗色种类,体短翅长,头球形或半球形,复眼红褐色,占据头的大部分,雄虫腹端向上左扭转弯向腹面,雌虫产卵器长而尖弯在腹下。 头蝇为同翅目叶蝉、飞虱等害虫的寄生性天敌;常见于草原和农田,低飞徘徊寻找寄主若虫产卵。我国的头蝇曾记述30多种,都是南方种类,近年我们报道了一些北方的新种,内蒙古则缺乏调查。本文初次描记内蒙3新种及1中国新记录种,模式标本均保存在北京农业大学昆虫标本室。     

毛盾圆蝇属一新种(双翅目:蝇科)

毛盾圆蝇属Lasiopelta Malloch,1928是个小属,迄今仅发现于东洋区。笔者在整理采自贵州的蝇类标本中,发现该属一新种。新种的模式标本保存于作者所在单位。斑翅毛盾圆蝇Lasiopelta maculipennis新种 雄 体长5mm。头底色黄,仅后头上部蓝黑色。眼具极疏微毛,几乎裸。额颇宽,头顶部约为一眼宽。间额暗红,具极薄的灰黄色粉被。额三角粉被金黄,细长,前段狭如线,     

中国突蜣蝇属一新种（双翅目：蜣蝇科）

记述中国蜣蝇科1新记录属:突蜣蝇属Tylotrypes及该属1新种:长毛突蜣蝇Tylotrypes longipilosasp.nov.。新种的鉴别特征为:体棕色,头浅棕色不具斑,胸深黄色具大量浅色毛,翅半透明具不规则灰色阴影,腹末第9背板宽阔,尾须短圆。     

川西北地区泉蝇属一新种及邻泉蝇属一新纪录

本文记述采自川西北地区泉蝇属一新种——黄龙泉蝇Pegomya huanglongensis 1♂及邻泉蝇属一新纪录种——兰得贝克邻泉蝇Paradelia,lundbeckii,并附Ⅱ、Ⅳ、Ⅴ腹板及尾器图。     

辽宁省植蝇属一新种(双翅目：花蝇科)

辽宁省植蝇属一新种（双翅目：花蝇科）张连富张大丽（辽宁省朝阳市卫生防疫站朝阳１２２０００）１９９５－０３－１５收稿,１９９６－０４－２６收修改稿·１０３·辽宁植蝇Ｌｅｕｃｏｐｈｏｒａｌｉａｏｎｉｎｇｅｎｓｉｓ新种（图１～４）雄性体长７．５ｍｍ。头眼裸...     

中国角潜蝇属莎草潜蝇亚属分类研究(双翅目,潜蝇科)

对中国角潜蝇属莎草潜蝇亚属进行了分类研究,确认我国现知2种：即福建角潜蝇C.(B.)fujianisca sp.nov和苔角潜蝇Cerodontha(Butomomyza)cornigera(dc Meijcrc)。除新种描述并附特征图外,还提供该亚属中国种类分种检索表。模式标本保存于中国科学院动物研究所动物标本馆。     

中国蚤蝇属记述：双翅目：蚤蝇科

中国蚤蝇属记述（双翅目：蚤蝇科）刘广纯,周尧（西北农业大学昆虫博物馆,陕西省杨陵区７１２１００）关键词双翅目,蚤蝇科,蚤蝇属,新种,分类学,中国蚤蝇属（ＰｈｏｒａＬａｔｒｅｉｌｌｅ,１７９６）是蚤蝇科中较大的类群;其身体绒黑（♂）或暗黑（♀）,中足胫...     

山西省棘蝇属三新种记述：双翅目：蝇科

本文记述采自山西省雁北地区的蝇科棘蝇属三个新种,分別与其近似种作了比较并绘有特征图。     

The bacterial species dilemma and the genomic-phylogenetic species concept

The number of species of Bacteria and Archaea (ca 5000) is surprisingly small considering their early evolution, genetic diversity and residence in all ecosystems. The bacterial species definition accounts in part for the small number of named species. The primary procedures required to identify new species of Bacteria and Archaea are DNA-DNA hybridization and phenotypic characterization. Recently, 16S rRNA gene sequencing and phylogenetic analysis have been applied to bacterial taxonomy. Although 16S phylogeny is arguably excellent for classification of Bacteria and Archaea from the Domain level down to the family or genus, it lacks resolution below that level. Newer approaches, including multilocus sequence analysis, and genome sequence and microarray analyses, promise to provide necessary information to better understand bacterial speciation. Indeed, recent data using these approaches, while meagre, support the view that speciation processes may occur at the subspecies level within ecological niches (ecovars) and owing to biogeography (geovars). A major dilemma for bacterial taxonomists is how to incorporate this new information into the present hierarchical system for classification of Bacteria and Archaea without causing undesirable confusion and contention. This author proposes the genomic-phylogenetic species concept (GPSC) for the taxonomy of prokaryotes. The aim is twofold. First, the GPSC would provide a conceptual and testable framework for bacterial taxonomy. Second, the GPSC would replace the burdensome requirement for DNA hybridization presently needed to describe new species. Furthermore, the GPSC is consistent with the present treatment at higher taxonomic levels.     

On the measurement of species diversity incorporating species differences

When pairwise differences (relatedness) between species are numerically given, the average of the species differences weighted by relative frequencies can be used as a species diversity index. This paper first theoretically develops the indices of this type, then applies them to forestry data. As examples of diversity indices, this paper explores the taxonomic diversity and the newly introduced amino acid diversity, which is a modification of the nucleotide diversity in genetics. The first, mathematical part shows that both indices can be decomposed into three inner factors; evenness of relative frequencies (=the Simpson index), the simple average over species differences regardless of relative frequencies, and the taxonomic or genetic balance in relative frequencies. The taxonomic diversity has another decomposition: the sum over the Simpson indices at all the taxonomic levels. The second part examines the effects of different forest management techniques on diversity. It is shown that a thinning operation for promoting survival of specific desirable species also contributed to increasing the taxonomic diversity. If we calculated only conventional indices that do not incorporate species relatedness, we would simply conclude that the thinning did not significantly affect the diversity. The theoretical developments of the first part complement the result, leading us to a better interpretation about contrasting vegetation structures. The mathematical results also reveal that the amino acid diversity involves redundant species, which is undesirable when measuring diversity; hence, this index is used to demonstrates crucial points when we introduce species relatedness. The results suggest further possibilities of applying diversity indices incorporating species differences to a variety of ecological studies.     

Finding unknown species in the genomes of extant species

Although many species have gone extinct, their genetic components might exist in extant species because of ancient hybridization. Via advances in genome sequencing and development of modern population genetics, one can find the legacy of unknown or extinct species in the context of available genomes from extant species. Such discovery can be used as a strategy to search for hidden species or fossils in conservation biology and archeology, gain novel insight into complex evolutionary history, and provide the new sources of genetic variation for breeding and trait improvement in agriculture.     

Exotic species richness and native species endemism increase the impact of exotic species on islands

Aim Exotic species pose one of the most significant threats to biodiversity, especially on islands. The impacts of exotic species vary in severity among islands, yet little is known about what makes some islands more susceptible than others. Here we determine which characteristics of an island influence how severely exotic species affect its native biota. Location We studied 65 islands and archipelagos from around the world, ranging from latitude 65° N to 54° S. Methods We compiled a global database of 10 island characteristics for 65 islands and determined the relative importance of each characteristic in predicting the impact of exotic species using multivariate modelling and hierarchical partitioning. We defined the impact of exotic species as the number of bird, amphibian and mammal (BAM) species listed by the International Union for Conservation of Nature (IUCN) as threatened by exotics, relative to the total number of BAM species on that island. Results We found that the impact of exotic species is more severe on islands with more exotic species and a greater proportion of native species that are endemic. Unexpectedly, the level of anthropogenic disturbance did not influence an island's susceptibility to the impacts of exotic species. Main conclusions By coupling our results with studies on the introduction and establishment of exotic species, we conclude that colonization pressure, or invasion opportunities, influences all stages of the invasion process. However, species endemism, the other important factor determining the impact of exotic species, is not known to contribute to introduction and establishment success on islands. This demonstrates that different factors correlate with the initial stages of the invasion process and the subsequent impacts of those invaders, highlighting the importance of studying the impacts of exotic species directly. Our study helps identify islands that are at risk of impact by exotics and where investment should focus on preventing further invasions.     

Ring species as demonstrations of the continuum of species formation

In the mid‐20th century, Ernst Mayr (1942) and Theodosius Dobzhansky (1958) championed the significance of ‘circular overlaps’ or ‘ring species’ as the perfect demonstration of the gradual nature of species formation. As an ancestral species expands its range, wrapping around a geographic barrier, derived taxa within the ring display interactions typical of populations, such as genetic and morphological intergradation, while overlapping taxa at the terminus of the ring behave largely as sympatric, reproductively isolated species. Are ring species extremely rare or are they just difficult to detect? What conditions favour their formation? Modelling studies have attempted to address these knowledge gaps by estimating the biological parameters that result in stable ring species (Martins et al. 2013), and determining the necessary topographic parameters of the barriers encircled (Monahan et al. 2012). However, any generalization is undermined by a major limitation: only a handful of ring species are known to exist in nature. In addition, many of them have been broken into multiple species presumed to be evolving independently, usually obscuring the evolutionary dynamics that generate diversity. A paper in this issue of Molecular Ecology by Fuchs et al. (2015), focused on the entire genealogy of a bulbul (Alophoixus) species complex, offers key insights into the evolutionary processes underlying diversification of this Indo‐Malayan bird. Their findings fulfil most of the criteria that can be expected for ring species (Fig.  1 ): an ancestor has colonized the mainland from Sundaland, expanded along the forested habitat wrapping around Thailand's lowlands, adjacent taxa intergrade around the ring distribution, and terminal taxa overlap at the ring closure. Although it remains unclear whether ring divergence has resulted in restrictive gene flow relative to that observed around the ring, their results suggest that circular overlaps might be more common in nature than currently recognized in the literature. Most importantly, this work shows that the continuum of species formation that Mayr and Dobzhansky praised in circular overlaps is found in biological systems currently described as ‘rings of species’, in addition to the idealized ‘ring species’.     

How to be a chaste species pluralist-realist: the origins of species modes and the synapomorphic species concept

The biological species (biospecies) concept applies only to sexually reproducing species, which means that until sexual reproduction evolved, there were no biospecies. On the universal tree of life, biospecies concepts therefore apply only to a relatively small number of clades, notably plants andanimals. I argue that it is useful to treat the various ways of being a species (species modes) as traits of clades. By extension from biospecies to the other concepts intended to capture the natural realities of what keeps taxa distinct, we can treat other modes as traits also, and so come to understand that theplurality of species concepts reflects the biological realities of monophyletic groups.We should expect that specialists in different organisms will tend to favour those concepts that best represent the intrinsic mechanisms that keep taxa distinct in their clades. I will address the question whether modes ofreproduction such as asexual and sexual reproduction are natural classes, given that they are paraphyletic in most clades.     

Cryptic species as a window into the paradigm shift of the species concept

The species concept is the cornerstone of biodiversity science, and any paradigm shift in the delimitation of species affects many research fields. Many biologists now are embracing a new “species” paradigm as separately evolving populations using different delimitation criteria. Individual criteria can emerge during different periods of speciation; some may never evolve. As such, a paradigm shift in the species concept relates to this inherent heterogeneity in the speciation process and species category—which is fundamentally overlooked in biodiversity research. Cryptic species fall within this paradigm shift: they are continuously being reported from diverse animal phyla but are poorly considered in current tests of ecological and evolutionary theory. The aim of this review is to integrate cryptic species in biodiversity science. In the first section, we address that the absence of morphological diversification is an evolutionary phenomenon, a “process” counterpart to the long‐studied mechanisms of morphological diversification. In the next section regarding taxonomy, we show that molecular delimitation of cryptic species is heavily biased towards distance‐based methods. We also stress the importance of formally naming of cryptic species for better integration into research fields that use species as units of analysis. Finally, we show that incorporating cryptic species leads to novel insights regarding biodiversity patterns and processes, including large‐scale biodiversity assessments, geographic variation in species distribution and species coexistence. It is time for incorporating multicriteria species approaches aiming to understand speciation across space and taxa, thus allowing integration into biodiversity conservation while accommodating for species uncertainty.     

Phylogeny and species delimitation of the C-genome diploid species in Oryza

The diploid Oryza species with C-genome type possesses abundant genes useful for rice improvement and provides parental donors of many tetraploid species with the C-genome (BBCC,CCDD).Despite extensive studies,the phylogenetic relationship among the C-genome species and the taxonomic status of some taxa remain controversial.In this study,we reconstructed the phylogeny of three diploid species with C-genome (Oryza officinalis,O.rhizomatis,and O.eichingeri) based on sequences of 68 nuclear single-copy genes.We obtained a fully resolved phylogenetic tree,clearly indicating the sister relationship of O.officinalis and O.rhizomatis,with O.eichingeri being the more divergent lineage.Incongruent phylogenies of the C-genome species found in previous studies might result from lineage sorting,introgression/hybridization and limited number of genetic markers used.We further applied a recently developed Bayesian species delimitation method to investigate the species status of the Sri Lankan and African O.eichingeri.Analyses of two datasets (68 genes with a single sample,and 10 genes with multiple samples) support the distinct species status of the Sri Lankan and African O.eichingeri.In addition,we evaluated the impact of the number of sampled individuals and loci on species delimitation.Our simulation suggests that sampling multiple individuals is critically important for species delimitation,particularly for closely related species.