Comparative micromorphology of nectariferous and nectarless labellar spurs in selected clades of subtribe Orchidinae (Orchidaceae)

Floral nectar spurs are widely considered to influence pollinator behaviour in orchids. Spurs of 21 orchid species selected from within four molecularly circumscribed clades of subtribe Orchidinae (based on Platanthera s.l., Gymnadenia-Dactylorhiza s.l., Anacamptis s.l., Orchis s.s.) were examined under light and scanning electron microscopes in order to estimate correlations between nectar production (categorized as absent, trace, reservoir), interior epidermal papillae (categorized as absent, short, medium, long) and epidermal cell striations (categorized as apparently absent, weak, moderate, strong). Closely related congeneric species scored similarly, but more divergent species showed less evidence of phylogenetic constraints. Nectar secretion was negatively correlated with striations and positively correlated with papillae, which were especially frequent and large in species producing substantial reservoirs of nectar. We speculate that the primary function of the papillae is conserving energy through nectar resorption and explain the presence of large papillae in a minority of deceit-pollinated species by arguing that the papillae improve pollination because they are a tactile expectation of pollinating insects. In contrast, the prominence of striations may be a 'spandrel', simply reflecting the thickness of the overlying cuticle. Developmentally, the spur is an invagination of the labellum; it is primarily vascularized by a single 'U'-shaped primary strand, with smaller strands present in some species. Several suggestions are made for developing further, more targeted research programmes. (C) 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160, 369-387.

兰科舌喙兰属的研究

对舌喙兰属的研究表明，该属具下列独特的特征：具一枚着生于茎基部的叶;叶片肉质、几平贴地表;花具硕大而伸出的蕊喙;药室基部延伸成花药管。该属花部器官在发育早期表现为典型的红门兰亚族特点，但在发育后期出现一些特有的性状。尽管舌喙兰属在植物体形态、花部形态和发育等方面表现出许多特化的性状，但染色体水平上与红门兰亚族东亚产的其他属并无明显差异。舌喙兰属植物一般喜欢在石灰岩地区生长，但有些各类也可在其他土壤中生长。野外观察表明扇唇舌喙兰通过食源性欺骗系统来吸引唯一的传粉者：芒康条蜂。其他各类虽亦有类似结构，但未进行观察。 ITS序列数据支持：1）舌喙兰属的6个种为单系类群;2）舌喙兰属、紫斑玉凤花和短距红门兰等植物体形态相似的类群构成关系较为密切的分支;3）主要分布于亚洲的无柱兰属和铣兜被兰属互为关系密切的姐妹群，它们与广布红门兰有较弱的联系。无柱兰－兜被兰类群和舌喙兰－紫斑玉凤花类群构成红门兰亚族中的一个分支;而二叶红门兰、西南手参、滇藏舌唇兰和欧洲产红门兰亚族的代表种类构成另一个分支。 总之，植物体形态，花部形态和发育、传粉模式、生态学特点以及分子数据，都表明舌喙兰属是一个特化的类群。 最后，对舌喙兰属进行了全面修订，确定该属具7个种，主要分布于中国，个别种类向南可达泰国和缅甸南部，向西可达不丹和尼泊尔。

Phylogenetics and biogeography of a spectacular Old World radiation of butterflies: the subtribe Mycalesina (Lepidoptera: Nymphalidae: Satyrini)

Background: Butterflies of the subtribe Mycalesina (Nymphalidae: Satyrinae) are important model organisms in ecology and evolution. This group has radiated spectacularly in the Old World tropics and presents an exciting opportunity to better understand processes of invertebrate rapid radiations. However, the generic-level taxonomy of the subtribe has been in a constant state of flux, and relationships among genera are unknown. There are six currently recognized genera in the group. Mycalesis, Lohora and Nirvanopsis are found in the Oriental region, the first of which is the most speciose genus among mycalesines, and extends into the Australasian region. Hallelesis and Bicyclus are found in mainland Africa, while Heteropsis is primarily Madagascan, with a few species in Africa. We infer the phylogeny of the group with data from three genes (total of 3139 bp) and use these data to reconstruct events in the biogeographic history of the group.,Results: The results indicate that the group Mycalesina radiated rapidly around the Oligocene-Miocene boundary. Basal relationships are unresolved, but we recover six well-supported clades. Some species of Mycalesis are nested within a primarily Madagascan clade of Heteropsis,while Nirvanopsis is nested within Lohora. The phylogeny suggests that the group had its origin either in Asia or Africa, and diversified through dispersals between the two regions, during the late Oligocene and early Miocene. The current dataset tentatively suggests that the Madagascan fauna comprises two independent radiations. The Australasian radiation shares a common ancestor derived from Asia. We discuss factors that are likely to have played a key role in the diversification of the group. Conclusions: We propose a significantly revised classification scheme for Mycalesina. We conclude that the group originated and radiated from an ancestor that was found either in Asia or Africa, with dispersals between the two regions and to Australasia. Our phylogeny paves the way for further comparative studies on this group that will help us understand the processes underlying diversification in rapid radiations of invertebrates.

Genetic structure and systematic relationships within the Ophrys fuciflora aggregate (Orchidaceae: Orchidinae): high diversity in Kent and a wind-induced discontinuity bisecting the Adriatic

A recent phylogenetic study based on multiple datasets is used as the framework for a more detailed examination of one of the ten molecularly circumscribed groups identified, the Ophrys fuciflora aggregate. The group is highly morphologically variable, prone to phenotypic convergence, shows low levels of sequence divergence and contains an unusually large proportion of threatened taxa, including the rarest Ophrys species in the UK. The aims of this study were to (a) circumscribe minimum resolvable genetically distinct entities within the O. fuciflora aggregate, and (b) assess the likelihood of gene flow between genetically and geographically distinct entities at the species and population levels. Fifty-five accessions sampled in Europe and Asia Minor from the O. fuciflora aggregate were studied using the AFLP genetic fingerprinting technique to evaluate levels of infraspecific and interspecific genetic variation and to assess genetic relationships between UK populations of O. fuciflora s.s. in Kent and in their continental European and Mediterranean counterparts. The two genetically and geographically distinct groups recovered, one located in England and central Europe and one in south-eastern Europe, are incongruent with current species delimitation within the aggregate as a whole and also within O. fuciflora s.s. Genetic diversity is higher in Kent than in the rest of western and central Europe. Gene flow is more likely to occur between populations in closer geographical proximity than those that are morphologically more similar. Little if any gene flow occurs between populations located in the south-eastern Mediterranean and those dispersed throughout the remainder of the distribution, revealing a genetic discontinuity that runs north-south through the Adriatic. This discontinuity is also evident in other clades of Ophrys and is tentatively attributed to the long-term influence of prevailing winds on the long-distance distribution of pollinia and especially seeds. A cline of gene flow connects populations from Kent and central and southern Europe; these individuals should therefore be considered part of an extensive meta-population. Gene flow is also evident among populations from Kent, which appear to constitute a single metapopulation. They show some evidence of hybridization, and possibly also introgression, with O. apifera.

Radicular anatomy of twelve representatives of the Catasetinae subtribe (Orchidaceae: Cymbidieae)

Considering that the root structure of the Brazilian genera belonging to the Catasetinae subtribe is poorly known, we describe the roots of twelve representatives from this subtribe. For anatomical analysis, the roots were fixed in FAA 50, preserved in ethanol 70% and sectioned at its medium region using razor blades. The sections were stained with 0.05% astra blue and safranin and mounted in glycerin. For the identification of starch we used Lugol ́s solution; for lignin, floroglucin chloridric; for lipids, Sudan III, and for flavanoids, potassium hydroxide. The relevant aspects were registered using a digital camera joined with an Olympus microspope (BX51 model). The structural similarities of all roots support the placement of the subtribe Catasetinae into the monophyletic tribe Cymbidieae. Some root features are restricted to one or two taxa and can be useful in the systematics of the subtribe. For example, the occurrence of flavonoidic crystals characterizes the genera Catasetum and Cychnodes, and the number of the velamen layers and the shape of the epivelamen cells are useful to confirm the taxonomic position of Clowesia amazonica. The presence of velamen and flavonoidic crystals was interpreted as an adaptation to the epiphytic habit.

The host specificity and climatic suitability of the gall flyCecidochares connexa(Diptera: Tephritidae), a potential biological control agent for Chromolaena odorata(Asteraceae) in Australia

The gall fly Cecidochares connexa (Diptera: Tephritidae) is a potential biological control agent for Chromolaena odorata in Australia. Its host specificity was determined against 18 species in the tribe Eupatorieae (Family Asteraceae) in which C. odorata belongs, in quarantine in Brisbane, Australia. Oviposition occurred and flies developed on only C. odorata and Praxelis clematidea, both of which are in the subtribe Praxelinae. P. clematidea is considered a weed outside tropical America. In both multiple-species-minus-C. odorata choice tests and single-species no-choice tests, the mean number of galls/plant was significantly greater on C. odorata (48 and 41, respectively) than on P. clematidea (2 and 9, respectively). There were also significantly more adults emerging from C. odorata (mean 129 and 169, respectively) in the two types of tests than from P. clematidea (1 and 8, respectively). Paired choice, multiple generation (continuation) and time dependent tests further clarified the extent that C. connexa could develop on P. clematidea. In these tests, the mean number of galls formed and the mean number of emerging adults were consistently less for P. clematidea than C. odorata and populations of C. connexa could not be maintained on P. clematidea. Galls were not seen on any other plant species tested. This study supports the results of host specificity testing conducted in seven other countries and confirms that C. connexa poses little risk to other plant species in Australia. C. connexa has been released in 10 countries and an application seeking approval to release in Australia has been submitted to the Australian Government.

Palinologia e taxonomia dos gêneros Elephantopus L., Orthopappus Gleason e Pseudelephantopus Rohr. (Subtribo Elephantopinae, Vernonieae- Asteraceae) ocorrentes no Brasil

A subtribo Elephantopinae tem sido alvo de poucos estudos taxonômicos e palinológicos, necessitando de uma reavaliação em seus limites. Assim, o presente estudo teve como proposta atualizar e ampliar o conhecimento de 13 espécies de Elephantopinae ocorrentes no Brasil através de um acurado estudo palinológico, da anatomia foliar e taxonômico, promovendo a delimitação das espécies dos gêneros Elephantopus (10 espécies) Orthopappus (uma espécie) e Pseudelephantopus (duas espécies)além de oferecer subsídios para posteriores análises filogenéticas. O material botânico utilizado foi obtido através de exsicatas depositadas nos herbários brasileiros e de material coletado em campo. Os grãos de pólen foram tratados pelo método acetolítico, sendo posteriormente mensurados, descritos, e analisados sob microscopia de luz e eletrônica de varredura. As eletromicrografias foram obtidas de grãos de pólen não acetolisados, as análises taxonômicas baseiam-se na metodologia clássica. A anatomia foliar deu-se através da metodologia usual. Os resultados mostram grãos de pólen médios, 3-porados, de exina equinolofada com malhas poligonais organizadas ou não em Elephantopus e Pseudelephantopus, podendo apresentar interrupção na malha poral em Elephantopus. Em Orthopapus os grãos de pólen são 3-colporados, de sexina subequinolofada. A anatomia foliar possibilitou a separação de E. hirtiflorus e E. riparius através da forma ou contorno da nervura principal (planoconvexo), nas demais espécies o contorno é biconvexo. As espécies apresentaram tricomas capitados bisseriados com 8 células, tricomas filamentosos 3-4 celulares, bem como filamentosos de célula distal globosa ou ovóide em E. biflorus, E. micropappus, E. tomentous e Orthopappus angustifolius. Registrou-se variação na ornamentação da cutícula podendo ser lisa ou estriada entre as espécies, bem como a presença de substâncias pécticas na epiderme e drusas nos parênquimas. Em relação aos microcaracteres florais, foram considerados de importância diagnóstica os lóbulos da corola, que variaram entre glandular, glabro e penicilado, este ultimo apenas em E. hirtiflorus, os ápices das anteras que variaram entre obtuso, retuso em E. hirtiflorus e apiculado, lancelolado em E. mollis e E. racemosus, a base da antera variou entre sagitada, caudada lisa em E. riparius e E. tomentosus e caudada em E. riparius. Os macrocaracteres que apresentaram maior valor taxonômico foram a cipsela e o papus, a organização das coflorescências, o número de flores por capítulo e limbo foliar. Neste trabalho aceitou-se a segregação dos três gêneros, com base nos caracteres analisados

Palinologia e taxonomia de espécies de Praxelis Cass. (subtribo Praxelinae, Eupatorieae-Asteraceae) ocorrentes no Brasil

Asteraceae é a segunda maior família de angiospermas com ca. 25.000 espécies distribuídas por todo mundo. Praxelis é o segundo maior gênero em número de espécies da subtribo Praxelinae, se caracteriza principalmente por apresentar capítulos cilíndricos/campanulados, receptáculo cônico e glabro, cipselas com carpopódio assimétrico e pápus com cerdas numerosas e barbeladas. No Brasil, as espécies predominam no Cerrado. O objetivo do presente trabalho foi analisar a palinologia e a taxonomia das espécies de Praxelis Cass. ocorrentes no Brasil. O material botânico utilizado foi obtido através de exsicatas depositadas nos herbários brasileiros. Os grãos de pólen foram acetolisados, medidos, descritos e ilustrados sob ML. Para observar detalhes da superfície e abertura, grãos de pólen não acetolisados foram analisados em MEV e, posteriormente, eletromicrografados. As peças florais foram colocadas sobre os mesmos suportes metálicos cobertos com fita dupla-face de carbono, previamente numerados. Para análise em MET, os grãos de pólen foram corados em cacodilato tamponado 0,125% OsO4, concentrados em pastilhas de ágar, e foram embebecidos em resina Epon-Araldite. As folhas, a capitulescência, o indumento do pedúnculo e o número de brácteas involucrais foram atributos relevantes para caracterizar as espécies, sobretudo o tamanho do invólucro e sua consistência. Foram caracterizados os grãos de pólen quanto à forma, ao tamanho, ao tipo de abertura, à polaridade e à constituição da exina. Foram descritos como: pequenos a médios, isopolares, oblato-esferoidais a subprolatos, 3(4)-colporados, com margem ornamentada, endoabertura com ou sem constricção, com presença de cávea, a sexina é espinhosa e sempre maior do que a nexina. Portanto, as análises palinológica e taxonômica foram utilizadas para segregar as espécies de Praxelis, porém apenas os atributos morfológicos externos foram mais informativos para diferenciar as espécies desse gênero.

东亚千里光族款冬亚族（菊科）的系统学

千里光族是菊科中最大的一个族，约含有120属3400多种，全世界分布。千里光族的族下分类与系统发育一直是菊科研究中的难点。Jeffrey&Chen(1984)和千里光亚族(7属)。自此以后，有关东亚款冬亚族的范畴、亚族内各属的系统位置与亲缘关系就成了千里光族系统学研究中争论的焦点，至今仍未有定论。陈艺(1997)在东亚款冬亚族内发表假橐吾属新属。根据Jeffrey&Chen(1984)的概念，东亚款冬亚族现含13属。东亚款冬亚族目前存在的系统学问题主要有：(1)毛冠菊属是否与款冬亚族内的款冬属及蜂斗菜属近缘;(2)狗舌草亚族所辖3属是否是款冬亚族的自然成员;(3)东亚款冬亚族13属的系统位置及其亲缘关系;(4)东亚款冬亚族的影响范畴。 针对上述问题，本文以发现新的系统学证据为主要目的，较为全面地研究了东亚款冬亚族及其相关类群的外部形态学，首次报道了18属45种植物的花部微观性状，19属64种105个居群的核形态学特征，10属15种植物花粉壁的超薄结构及13属28种植物花粉的外壁纹饰，3种植物的胚胎发育和6种植物的ITS基因序列;并对所获得的证据进行了比较与综合分支分析。根据所获系统学资料，对东亚款冬亚族的上述系统学问题进行了讨论。主要实验结果及结论总结如下。 1. 外部形态 较为全面地观察与分析了东亚款冬亚族及其相关类群外部形态性状及其演化趋势，指出根状茎分枝方式、幼叶出土性状、花部茎基部叶是否宿存、叶柄是否纤维状宿存、花序托空心或实心、花药基部结构等不被以前作者重视或忽视的形态学性状可能具有重要的系统学价值。外部形态上，毛冠菊属与千里光族内的千里光属与款冬属等类群没有亲缘关系，而与紫菀族存在一定的渊源;狗舌草亚族则介于千里光亚族和款冬亚族之间;东亚款冬亚族13属可依据外部形态划分为6个属群。 2. 花部微观性状 东亚款冬亚族及其相关类群的花部微观性状主要包括：花药顶端不育组织、花药药室内壁、花药基部、花药领、花柱分枝顶端、花柱毛被、花柱分枝内表面构型、果柄细胞列数等。花部微观性状研究表明：毛冠菊属似乎应作为紫菀族中的一个孤立属;狗舌草亚族在某些衍征上与千里光亚族接近，而它的原始性状则类似于款冬亚族;根据花部微观性状对东亚款冬亚族的13个属划分出的自然属群与形态性状分析所得结果基本一致。 3. 核形态学 毛冠菊属的染色体基数为x=9，与紫菀族相同：而与千里光族和旋覆花族的染色体x=10存在显著的区别。狗舌草亚族中新发现2n=24、60、72三个染色体数目，亚族内染色体基数之间的演化关系不清楚，利用染色体基数来探讨狗舌草亚族所辖属的系统位置和属间关系仍还比较困难。东亚款冬亚族的染色体基数主要有x=30、29、28、27、26;款冬亚族中普遍存在的染色体基数x=30可能有3种来源;核型可分为2A、3A、2B三大类型，虽然三种类型之间的染色体基数(x=30)有可能是不同起源的，但从整个千里光族来看，3A、2B应是较进化的类型。根据核形态学特征，东亚款冬亚族可分为款冬型、蟹甲草型和大吴风草型三类。在蟹甲草型染色体进化支上，存在染色体的非整倍性下降趋势。东亚款冬亚族存在的种内多倍性可能与不同的生境有关。 4. 花粉学 通过对东亚款冬亚族及其相关类群的花粉壁超微结构与扫描电镜观察，发现花粉壁超微结构存在“千里光型”和“向日葵型”两种类型。扫描电镜下，花粉外壁均为刺状纹饰，但在刺的长短、刺部是否膨大、刺基膨大上的纹饰以及刺基之间的纹饰等方面存在差别。毛冠菊属的花粉性状组合支持将其置于紫菀族中。狗舌草亚族的花粉性状与款冬亚族的有些属相似。款冬亚族各属的花粉生状组合所划分的属群与形态学、核形态学等方面的研究结果较为一致。 5. 胚胎学 款冬、掌裂橐吾和珠毛蟹甲草共同拥有药壁发育双子叶型;绒毡层发育属“The Comos bipinnatus”型;成熟花粉为3细胞型;单珠被，薄珠心，倒生胚珠;具发育相似的珠被绒毡层：胚橐发育4孢子型等胚胎学特征，但它们在胚囊发育方式、反足细胞数目、发殖物候上还存在区别。三属代表植物的胚胎学研究支持将它们作为同一亚族的成员。 6. 分子数据 利用本研究测得的华千里光属4种、狗舌草属1种和大吴风草属的ITS－1和ITS－2基因序列，结合从Genbank中得出的千里光族5属8种植物得ITS序列，用PAUP软件进行分析。研究结果表明，染色体基数、花粉超微结构、叶型和叶脉等性状在ITS分支图上存在趋同进化;华千里光属和狗舌草属不是单系群。并讨论了一些分类群的亲缘关系。 7. 分支分析 选择东亚款冬亚族和狗舌草亚族各属的代表种作为终端代表类群进行分支分析;分支分析表明染色体基数、与头状花序有关的性状、叶型及叶脉等性状存在较多的平行与逆转进化，而根状茎分枝类型、花部微观性状以及花粉性状则表现出较大的一致性。根据分支结果，作者认为应建立包括狗舌草亚族在内的广义东亚款冬亚族。 8. 系统学 毛冠菊属的性状组合支持将其置于紫菀族，排除在千里光族之外。广义东亚款冬亚族可分为7个属群：蟹甲草属群(包括蟹甲草属，华蟹甲草属，小蟹甲草属，兔儿伞属，蟹甲木属)、毛柱菊属群(毛柱菊属)、橐吾属群(包括橐吾属，垂头菊属，假橐吾属)、狗舌草属群(狗舌草属，华千里光属，羽叶千里光属)、多榔菊属群(多榔菊属)、大吴风草属群(大吴风草属)、款冬属群(款冬属，蜂斗菜属)。总结与讨论了各属群的系统位置、亲缘关系与存在的分类学问题。描述了华千里光属1新种。

鰋鮡鱼类(Glyptosternoid fishes)的系统进化和动物地理学研究

鰋鮡鱼类共包括9 属43 种（亚种），隶属于鲇形目（Siluriformes）鮡科 （Sisoridae）鰋鮡亚科（Glyptosternae）中鰋鮡族（Tribe Glyptosternini）的鰋鮡 亚族（Subtribe Glyptosternina）。鰋鮡鱼类形态上的共同特征为：无胸吸着器，胸、 腹鳍水平展开，第一根鳍条完全分节或在外缘生出许多软骨细条，被外表皮所裹， 在腹面看到的是许多与分节或软骨细条大致对应的横纹皱褶。鰋鮡鱼类集中分布 于青藏高原周边的水系中，部分属种向西分布到了中亚地区的阿姆河上游，是适 应山区急流环境的一群鱼类。近年来一系列的研究表明，鰋鮡鱼类为一单系类群， 它的起源和演化与青藏高原的隆升有着直接的关系。鰋鮡鱼类的系统发育研究， 可以为青藏高原隆升的年代、幅度和形式提供间接的证据，其系统发育树的拓扑 结构也直接反映了东喜马拉雅地区诸水系的形成与演变。 本研究对鰋鮡鱼类9 属进行了系统整理。1. 发现并描述了异齿鰋属 （Oreoglanis）两新种，分别为分布于景东无量山（澜沧江水系）的景东异齿鰋 （O. jingdongensis）和分布于怒江水系南景河和南滚河的无斑异齿鰋（O. immaculatus）。认为分布于中国的异齿鰋属鱼类均属于尖须异齿鰋种组（O. siamensis species group）。指出区分异齿鰋属两个种组：尖须异齿鰋种组和细尾 异齿鰋种组（O. delacouri species group）的特征是下唇中部是否具有中央缺刻， 尾型的差别（新月型尾或凹型尾）不能用来区分两个种组，给出了异齿鰋属的检 索表，并绘制了异齿鰋属鱼类分布图。2. 对鮡属（Pareuchiloglanis）鱼类进行了 系统整理，通过外部形态度量性状的比较，认为分布于澜沧江水系的，曾经被鉴 定为扁头鮡（P. kamengensis）的标本，应属于大鳍鮡（P. macropterus），扁头鮡 和大鳍鮡之间的最明显的差别在于腹鳍前长的不同。前者的腹鳍前长为体长的 53.2-64.9%，后者的腹鳍前长均不达体长的50%。3. 通过比较金沙江水系分布的 5 种鮡属鱼类，中华鮡（P. sinensis）、前臀鮡（P. anteanalis）、壮体鮡（P. robusta）、 四川鮡（P. sichuanensis）和天全鮡（P. tianquanensis），认为天全鮡和四川鮡之 间分布水系重叠，外部形态亦无差别，天全鮡很可能为四川鮡的同物异名。给出 了鮡属鱼类的系统检索表，并绘制了鮡属鱼类分布图。利用分子系统学的原理和方法对鰋鮡鱼类进行系统发育研究。测定了6 属 15 种鰋鮡鱼类和鮡科中非鰋鮡鱼类4 属7 种共28 个体的线粒体Cyt b 基因部分 片段和全序列（1138 bp），结合从GenBank 下载的相关类群相同的基因序列，以 魾属（Bagarius）的巨魾（B. yarrelli），纹胸鮡属（Glyptothorax）的穴形纹胸鮡 （G. cavia）、亮背纹胸鮡（G. dorsalis）、扎那纹胸鮡（G. zainaensis），福建纹胸 鮡（G. fukiensis fukiensis）、海南纹胸鮡（G. fukiensis hainanensis），黑鮡属（Gagata） 的长丝黑鮡（G. dolichonema）以及褶鮡属（Pseudecheneis）的黄斑褶鮡（P. sulcatus） 和无斑褶鮡（P. immaculatus）作为外类群，采用贝叶斯法（Bayesian）、最简约 法（maximum pasimony, MP）和邻接法（neighbour-joining, NJ）构建系统发育树。 结果显示： 1. 鰋鮡鱼类为一单系类群，并且与褶鮡属互为姐妹群关系； 2. 原鮡属、鰋属和凿齿鮡属是鰋鮡鱼类的三个基部类群； 3. 异齿鰋属构成为一个单系群，大鳍异齿鰋最早从该属的基部分化出来； 4. 石爬鮡属构成一个单系，并与分布于金沙江水系的中华鮡＋前臀鮡构成姐妹 群，黄石爬鮡和青石爬鮡的单倍型相互交错；显示两个物种的分类是不合适的， 而是同一水系不同支流种群之间梯度变异的例子，依据本次研究所得出的三个分 支图，结合青石爬鮡自西至东分布于金沙江、雅砻江、大渡河、青衣江、岷江等 的分布格局以及形态特征的分布，显示形态特征的分布变化有以下趋势：自西至 东，腹鳍位置逐渐前移；颌须渐趋缩短；胸鳍趋向发达、伸达腹鳍起点。这些变 化趋势是同一水系不同支流种群之间梯度变异的极好例子； 5. 分布于澜沧江以西（包括澜沧江）水系的鮡属鱼类（扁头鮡、细尾鮡、短鳍 鮡）与分布于怒江和伊洛瓦底江水系的拟鰋属鱼类构成为一支，并且二者共同与 分布于元江上游（红河水系）的大孔鮡构成为单系。其中，短体拟鰋和拟鰋互为 姐妹种；而扁头鮡和短鳍鮡也互为姐妹种；细尾鮡的系统地位则尚不能确定； 6. 无论在MP 树、贝叶斯树还是NJ 树中，石爬鮡属、鮡属、拟鰋属和异齿鰋属 构成一个单系，并且支持率达到了100％。 7. 鰋属位于鰋鮡鱼类的基部，是较早就从鰋鮡鱼类祖先中演化出来的一个类群， 鰋类的口吸盘是一个趋同性状，是在急流环境条件下形成的一种适应性性状，在 鰋类各属中不是同源特征； 8. 鮡属鱼类不是一个单系类群，分布于金沙江流域的鮡属鱼类与同流域分布的石爬鮡属鱼类聚成一支；澜沧江及其以西水系分布的鮡属鱼类与同流域分布的拟 鰋属鱼类聚成一支，之后这两支又同异齿鰋属共同构成为一个大支。 结合鰋鮡鱼类的系统发育分支图对其动物地理学进行研究。鰋鮡鱼类是由类 似纹胸鮡属（Glyptothorax）鱼类的祖先演化而来，鰋属（Exostoma）和凿齿鮡 属（Glaridoglanis）是较早就从从类似原鮡的祖先中演化出来，鮡属、石爬鮡属、 拟鰋属和异齿鰋属这一大支由类似原鮡的祖先演化而来。在青藏高原强烈隆起等 重大地理隔离事件发生之前，类似于现生的原鮡属鱼类已经广布喜马拉雅山脉东 西两侧。在青藏高原强烈隆起等重大地理隔离事件发生后，鰋鮡鱼类在相同的地 理隔离下独自演化为现在的分布格局。

Radiation and diversification within the Ligularia-Cremanthodium-Parasenecio complex (Asteraceae) triggered by uplift of the Qinghai-Tibetan Plateau

The Ligularia-Cremanthodium-Parasenecio (L-C-P) complex of the Tussilagininae (Asteraceae: Senecioneae) contains more than 200 species that are endemic to the Qinghai-Tibetan Plateau in eastern Asia. These species are morphologically distinct; however, their relationships appear complex. A phylogenetic analysis of members of the complex and selected taxa, of the tribe Senecioneae was conducted using chloroplast (ndhF and trnL-F) and nuclear (ITS) sequences. Phylogenetic trees were constructed from individual and combined datasets of the three different sequences. All analyses suggested that Doronicum, a genus that has been included in the Tussilagininae, should be excluded from this subtribe and placed at the base of the tribe Senecioneae. In addition, the Tussilagininae should be broadly circumscribed to include the Tephroseridinae. Within the expanded Tussilagininae containing all 13 genera occurring in eastern Asia, Tussilago and NSPetasites diverged early as a separate lineage, while the remaining I I genera comprise an expanded L-C-P complex clade. We suggest that the L-C-P clade, which is largely unresolved, most likely originated as a consequence of an explosive radiation. The few monophyletic subclades identified in the L-C-P clade with robust support further suggest that some genera of Tussilagininae from eastern Asia require generic re-circumscriptions given the occurrence of subclades containing species of the same genus in different parts of the phylogentic tree due to homoplasy of important morphological characters used to delimit them. Molecular-clock analyses suggest that the explosive radiation of the L-C-P complex occurred mostly within the last 20 million years, which falls well within the period of recent major uplifts of the Qinghai-Tibetan Plateau between the early Miocene to the Pleistocene. It is proposed that significant increases in geological and ecological diversity that accompanied such uplifting, most likely promoted rapid and continuous allopatric speciation in small and isolated populations, and allowed fixation or acquisition of similar morphological characters within unrelated lineages. This phenomenon, possibly combined with interspecific diploid hybridization because of secondary sympatry during relatively stable stages between different uplifts, could be a major cause of high species diversity in the Qinghai-Tibetan Plateau and adjacent areas of eastern Asia. (c) 2005 Elsevier Inc. All rights reserved.

Molecular systematics and biogeography of Crawfurdia, Metagentiana and Tripterospermum (Gentianaceae) based on nuclear ribosomal and plastid DNA sequences

Background and Aims The systematic position of the genus Metagentiana and its phylogenetic relationships with Crawfurdia, Gentiana and Tripterospermum have not been explicitly addressed. These four genera belong to one of two subtribes (Gentianinae) of Gentianeae. The aim of this paper is to examine the systematic position of Crawfurdia, Metagentiana and Tripterospermum and to clarify their phylogenetic affinities more clearly using ITS and trnL intron sequences.Methods Nucleotide sequences from the internal transcribed spacers (ITS) of nuclear ribosomal DNA and the plastid DNA trnL (UAA) intron were analysed phylogenetically. Ten of fourteen Metagentiana species were sampled, together with 40 species of other genera in the subtribe Gentianinae.Key Results The data support several previously published conclusions relating to the separation of Metagentiana from Gentiana and its closer relationships to Crawfurdia and Tripterospermum based on studies of gross morphology, floral anatomy, chromosomes, palynology, embryology and previous molecular data. The molecular clock hypothesis for the tested sequences in subtribe Gentianinae was not supported by the data (P < 0.05), so the clock-independent non-parametric rate smoothing method was used to estimate divergence time. This indicates that the separation of Crawfurdia, Metagentiana and Tripterospermum from Gentiana occurred about 11.4-21.4 Mya (million years ago), and the current species of these three genera diverged at times ranging from 0.4 to 6.2 Mya.Conclusions The molecular analyses revealed that Crawfurdia, Metagentiana and Tripterospermum do not merit status as three separate genera, because sampled species of Crawfurdia and Tripterospermum are embedded within Metagentiana. The speciation and rapid radiation of these three genera is likely to have occurred in western China as a result of upthrust of the Himalayas during the late Miocene and the Pleistocene.