Molecular Phylogeny of the Genus Paramesotriton (Caudata: Salamandridae)

To elucidate the phylogeny of the genus Paramesotriton (Caudata: Salamandridae), we investigated three mitochondrial DNA gene fragments (1207 bp in total) of cytochrome b, ND2, and ND4 for its six recognized species. The phylogenetic relationships within Paramesotriton were reconstructed by maximum parsimony (MP) and maximum likelihood (ML) methods. Phylogenetic trees (MP and ML trees) that were constructed from the combined data set of the three gene fragments indicated that all six species of Paramesotriton formed a monophyletic group, with P. caudopunctatus as basal to the other five species. This result suggests that P. fuzhongensis is a valid species in Paramesotriton.     

尾斑瘰螈的核型和C带研究

用常规Giemsa染色和BSG技术研究了尾斑瘰螈的核型和C带。该螈的染色体数 为2n=24,包括9对中部着丝粒染色体和3对亚中部着丝粒染色体(Nos. 7、10、11);BSG显带处理后全部染色体都显示了弱的着丝粒带,同时还显示了46条近着丝粒区插入带; 其核型和C带均不同于已研究过的国内蝾螈科动物,未发现与性别有关的异形色体。     

织金瘰螈生物学特性及保护措施

织金瘰螈Paramesotriton zhijinensis是2008年才发现的中国特有珍稀两栖动物.发现于贵州省织金县,它是世界上最稀少的两栖动物之一,在世界其它各地至今还没有被发现,也是被关注和研究最少的濒危动物之一.由于生境的逐渐丧失、环境的恶化、人为的严重干扰等诸多因素导致其种群数量急剧减少.以现在的种群数量和消亡速度来看,如不善加保护,它很可能不久就会灭绝.本文对织金瘰螈的分布区域、栖息环境、体型特征、生活习性、食性及种群资源状况进行了简单分析,希望能为该物种的资源保护提供重要的理论依据.     

富钟瘰螈和广西瘰螈泄殖系统研究

用解剖学技术研究和比较了富钟瘰螈Paramesotriton fuzhongensis和广西瘰螈Paramesotriton guangxiensis的泄殖系统。结果显示两种瘰螈的泄殖系统基本相同,仅生殖腺在颜色和形状上稍有差异。它们具有后位肾,雄螈肾脏由副睾肾和尾肾组成。但雄螈尾肾发出的多条集尿管并不通往后位肾管而是向后汇合成副尿管通往泄殖腔。后位肾管主要起输精作用,而副尿管则负责输尿。结果揭示雄性泄殖管道有功能分离的趋势,这在两栖类中处于较高进化水平。     

Species monophyly

In biological systematics, as well as in the philosophy of biology, species and higher taxa are individuated through their unique evolutionary origin. This is taken by some authors to mean that monophyly is a (relational) property not only of higher taxa, but also of species. A species is said to originate through speciation, and to go extinct when it splits into two daughter species (or through terminal extinction). Its unique evolutionary origin is said to bestow identity on a species through time and change, and to render species names rigid designators. Species names are thus believed to function just like names of supraspecific taxa. However, large parts of the Web of Life are composed of species that do not have a unique evolutionary origin from a single population, lineage or stem-species. Further, monophyly is an ambiguous concept if it is defined simply in terms of 'unique evolutionary origin'. Disambiguating the concept by defining a monophyletic taxon as 'a taxon that includes the ancestor and all, and only, its descendant' renders monophyly inapplicable to species. At the heart of the problem lies a fundamental distinction between species and monophyletic taxa, where species form mutually exclusive reticulated systems, while higher taxa form inclusive hierarchical systems. Examples are given both at the species level and below to illustrate the problems that result from the application of the monophyly criterion to species. The conclusion is that the concepts of exclusivity and monophyly should be treated as non-overlapping: exclusivity marks out a species synchronistically, i.e. in the present time. Monophyly marks out clades (groups of species) diachronistically, i.e. within an historical dimension.     

Comparing Species Assemblages Via Species Accumulation Curves

Summary Comparing species assemblages given incidence‐based data is of importance in ecological studies, often done by a visual inspection of estimated species accumulation curves or by an ad hoc use of 95% pointwise confidence bands of these curves. It is shown that comparing species assemblages is a challenging problem. A χ² test is proposed. An adjustment using an eigenvalue decomposition is proposed to overcome computational difficulties. The bootstrap method is also suggested to approximate the distribution of the proposed test statistic. The eigenvalue adjusted (Eva) χ² test and the Eva‐bootstrap test are assessed by a simulation study. Both the Eva‐χ² and the Eva‐bootstrap tests are applied to a study that involves two woody seedling species assemblages.     

龙里瘰螈与织金瘰螈的核型

用常规涂片法对贵州产龙里瘰螈Paramesotriton longliensis与织金瘰螈P.zhijinensis的染色体核型进行了研究。结果显示,龙里瘰螈的核型为2n=24=16m+8sm,染色体臂数NF=48,其中No.7、10、11、12为亚中着丝粒染色体(sm),其余均为中着丝粒染色体(m);织金瘰螈的核型为2n=24=20m+4sm,NF=48,其中No.9、11为sm,其余均为m。2种瘰螈的核型存在差异,可为2个物种的成立提供细胞遗传学佐证。     

Species orthogonalization

We discuss the general formation of complementary behaviors, functions and forms in biological species competing for resources. We call orthogonalization the related processes on macro and micro-level of a self-organized formation of correlations in the species properties. Orthogonalization processes could be, for example, easily observed in sympatric speciation, as we show in numerical studies carried out with a new population equation. As a practical result, we find that the number of species is proportional to the effective richness of resources and depends on their history.     

江西省中国瘰螈分布的新记录

江西地区已有两栖动物计2目8科38种(Zhu,1994),其中有尾类已有记录为3种:大鲵(Andriasdavidianus)、东方蝾螈(Cynops orientalis)和肥螈(Paehytriton brevipes)。最近笔者在江西永新县深远山自然保护区陆生脊椎动物调查中,发现了蝾螈科(Salamandridae)瘰螈属(Paramesotrlton)一种有尾类动物,为江西省分布的新记录。现报道如下,作为该物种地理分布的资料参考。1采集时间和地点中国瘰螈[Paramesotriton chinensis(Gary,1895)]标本由宋玉赞采集于2006年5月17日江西省永新县深远山自然保护区船坪附近小溪,海拔352—576m,地理坐标为26°45.1…     

Phylogenetic Relationships of the Genus Paramesotriton （Caudata： Salamandridae） with the Description of a New Species from Qixiling Nature Reserve,Jiangxi, Southeastern China and a Key to the species

The matrilineal genealogy of the genus Paramesotriton is hypothesized based on DNA sequences from mitochondrial NADH subunit two （ND2） and its flanking tRNAs （tRN^Arp and a partial tRNA^Ala）. The genealogy identifies a highly divergent, unnamed lineage from Qixiling Nature Reserve, Jiangxi, China and places it as the sister taxon of P. chinensis. The newly discovered population differs from other congeners by several features of external morphology including having large clusters of dark brown conical warts on the dorsum of the head, lateral surface of the body and dorsolateral ridges. Its intermittent dorsal vertebral ridge is the same color as other parts of the dorsum and tail narrows gradually from the base to the tip. Further, the new population differs from all congeners by an uncorrected P-distance of more than 9.38% in ND2. Consequently, we describe the new species of Asian warty newt （Salamandridae） as Paramesotriton qixilingensis sp. nov.     

Species and paleoanthropology

The biotic world is self-evidently “packaged” into units, of which the most basic is the species. It is necessary to develop an accurate understanding of what species are and how they are to be identified before we can proceed to more complex analyses of the evolutionary histories and relationships of extinct and extant taxa at all levels of the systematic hierarchy. In this article, we review the major species concepts current today among paleoanthropologists, and examine the limitations of their applicability to practical studies of extant and extinct faunas. The primary such limitation for paleoanthropologists is the fact that all major species definitions stress reproductive continuity (whether by exclusionary or inclusionary mechanisms), a quality that is inferential at best among forms known only as fossils (and, in many cases, in the extant fauna as well). The only reliable signal as to species status in the fossil record is morphology, yet speciation carries with it no specifiable quantity of morphological innovation. Some groups with autapomorphies are not species, and some species do not bear autapomorphies. How, then, are we to recognize species in the hominid and other fossil records? Noting that osteodental differences among congeneric primate species tend to be subtle, and that when consistent identifiable “morphs” can be found at least as many species are present, we recommend equating morphs based on several characters with species—realizing that only one or two distinctive characters may not make a morph. In this way, our views of the phylogenetic histories of higher taxa may be oversimplified, but their essential patterns will not be distorted.     

物种与物种多样性

本文首先讨论生物物种的科学概念和生物学本质，分析物种客观存在的自然属性和物种概念的局限性，认为物种的生物学属性和物种多样性的科学属性之间有着本质联系。物种多样性研究的实质是研究生物物种的生物学多样性。度量物种多样性程度有多种方法，但物种数目是物种多样性程度最直接、也是最基本的表达，估计物种多样性数目是当前国际上物种多样性研究的核心与热点内容。物种多样性产生的根源是物种形成，物种绝灭速率是维持物种多样性的关键因素。本文简要总结了物种形成与绝灭的基本模式和机制，通过分析生物地理区系与物种多样性研究的密切关系，说明物种的区系成份分析是物种多样性大尺度格局研究的重要内容。     

The Importance of Species Traits for Species Distribution on Oceanic Islands

Understanding species'' ability to colonize new habitats is a key knowledge allowing us to predict species'' survival in the changing landscapes. However, most studies exploring this topic observe distribution of species in landscapes which are under strong human influence being fragmented only recently and ignore the fact that the species distribution in these landscapes is far from equilibrium. Oceanic islands seem more appropriate systems for studying the relationship between species traits and its distribution as they are fragmented without human contribution and as they remained unchanged for a long evolutionary time. In our study we compared the values of dispersal as well as persistence traits among 18 species pairs from the Canary Islands differing in their distribution within the archipelago. The data were analyzed both with and without phylogenetic correction. The results demonstrate that no dispersal trait alone can explain the distribution of the species in the system. They, however, also suggest that species with better dispersal compared to their close relatives are better colonizers. Similarly, abundance of species in the archipelago seems to be an important predictor of species colonization ability only when comparing closely related species. This implies that analyses including phylogenetic correction may provide different insights than analyses without such a correction and both types of analyses should be combined to understand the importance of various plant traits for species colonization ability.     

Shoot-Level Flammability of Species Mixtures is Driven by the Most Flammable Species: Implications for Vegetation-Fire Feedbacks Favouring Invasive Species

Invasive species can cause shifts in vegetation composition and fire regimes by initiating positive vegetation-fire feedbacks. To understand the mechanisms underpinning these shifts, we need to determine how invasive species interact with other species when burned in combination and thus how they may influence net flammability in the communities they invade. Previous studies using litter and ground fuels suggest that flammability of a species mixture is nonadditive and is driven largely by the more-flammable species. However, this nonadditivity has not been investigated in the context of plant invasions nor for canopy fuels. Using whole shoots, we measured the flammability of indigenous-invasive species pairs for six New Zealand indigenous and four globally invasive plant species, along with single-species control burns. Our integrated measure of flammability was clearly nonadditive, and the more-flammable species per pairing had the stronger influence on flammability in 83% of combinations. The degree of nonadditivity was significantly positively correlated with the flammability difference between the species in a pairing. The strength of nonadditivity differed among individual flammability components. Ignitability and combustibility were strongly determined by the more-flammable species per pair, yet both species contributed more equally to consumability and sustainability. Our results suggest mechanisms by which invasive species entrain positive vegetation-fire feedbacks that alter ecosystem flammability, enhancing their invasion. Of the species tested, Hakea sericea and Ulex europaeus are those most likely to increase the flammability of New Zealand ecosystems and should be priorities for management.     

山东省的长肢林蛙种组物种

前人报道天津和山东有日本林蛙的分布,但也有学者表示怀疑。本文报道采集于山东徂徕山的该类物种。从成体量度和蝌蚪唇踟式来看,与现报道的镇海林蛙和峨眉林蛙有一定差异。该物种体型大小与峨眉林蛙相近似,唇齿式为1：2-2／111     

尾斑瘰螈泌尿器官的形态组织学观察

本文采用组织学和形态学方法对尾斑瘰螈的泌尿器官进行研究。结果表明:尾斑瘰螈的泌尿器官主要包括肾脏、输尿管和膀胱。其肾脏为实质性器官,主要由肾小体、肾小管构成;肾实质出现区域分隔,肾小体数量较少,肾小管分为颈段、近曲小管、中间段、远曲小管;其间未发现淋巴组织以及与生殖有关的结构。输尿管由单层立方上皮过渡到假复层立方上皮;膀胱壁由2~3层细胞变移上皮构成。     

Species concept and speciation

Defining and recognizing a species has been a controversial issue for a long time. To determine the variation and the limitation between species, many concepts have been proposed. When a taxonomist study a particular taxa, he/she must adopted a species concept and provide a species limitation to define this taxa. In this paper some of species concepts are discussed starting from the typological species concepts to the phylogenetic concept. Positive and negative aspects of these concepts are represented in addition to their application.     

Invasive Species and Evolution

Invasive species are a major threat to modern ecosystems and cause billions of dollars in economic damage annually. The long-term impacts of species invasions are difficult to assess on ecological timescales available to biologists, but the fossil record provides analogues that allow investigation of the long-term impacts of species invasions. Two case studies of ancient invasions, the Late Devonian Biodiversity Crisis (~375?million years ago) and the Late Ordovician Richmondian Invasion (~446?million years ago), provide insight into the effect of invasive species on extinction, speciation, and ecosystem structuring. During both intervals, invasive species are characterized by broad ecological tolerances, broad geographic ranges, and higher-than-average survival potential through the crisis interval. Among the native species, narrowly adapted ecological specialists are more likely to become extinct, while broadly-adapted generalist species persisted through the invasion interval by modifying aspects of their ecological niche through niche evolution. In addition, formation of new species practically stopped during the invasion intervals due to reduced opportunities for geographic isolation and speciation. The results of these impacts produced post-invasion biotas with less diversity, greater biotic homogenization between regions, and a lack of new species forming. Conservation efforts to eradicate invasive species may help mitigate these outcomes in the current biodiversity crisis.     

Host Specificity of Pathogenic Pythium Species: Implications for Tree Species Diversity

In the Janzen–Connell hypothesis, host-specific natural enemies enhance species diversity and influence the structure of plant communities. This study tests the explicit assumption of host specificity for soil pathogens of the genus Pythium that cause damping-off disease of germinating seeds and seedlings. We isolated Pythium spp. from soil of a tropical forest in Panama. Then, in an inoculation experiment, we determined the pathogenicity of 75 tropical isolates of unknown pathogenicity and seven pathogenic temperate isolates of Pythium on seeds and/or seedlings of eight tropical tree species. Only three tropical isolates, one identified as P. ultimum and two as P. aphanidermatum , were pathogenic. Tropical pathogenic isolates were pathogenic on 4–6 of eight tree species. Temperate isolates were pathogenic on 0–4 of eight species, indicating that some tropical tree species are susceptible to novel isolates of Pythium . No tree species was susceptible to all isolates and two species were not susceptible to any isolate. Collectively, these results indicate that these Pythium isolates vary widely in their pathogenicity, causing differential mortality of potential host species; likewise, the tree species vary in their susceptibility to a given Pythium isolate. These differences in pathogenicity and susceptibility indicate some support for the Janzen–Connell assumption of host specificity. While they are not restricted to a single species, their intermediate level of specificity suggests that Pythium spp. have the potential to have some effect on forest community structure and diversity.