横断山特有植物区系的物种多样性与生物地理学研究

前人对横断山区特有植物的宏生态学研究已有一定的资料积累，对横断山区在全球生物多样性保护中的关键地位和特有现象已有基本共识：（1）横断山区是全球生物多样性关键地区和生物多样性优先重点保护的热点地区之一；（2）横断山区不仅是中国的三大特有植物分布中心之一，而且是新特有中心和物种分化中心，特有现象的生态成因大于历史成因。横断山区种子植物种类丰富，且具有较高的特有现象，其中既有古特有成分也有新特有成分但更多的是新特有成分。但目前，关于横断山区特有现象与生态特征、特有种分布与物种丰富度、特有种丰富度与海拔梯度以及植被的关系等仍缺乏深入的研究。针对上述问题，本论文初步研究了横断山区（1）特有种的生活型、种子散布方式、传粉方式和繁育系统等生态特征，各生态特征之间的相关关系，以及它们的进化地位；（2）特有种的水平分布格局及环境成因；和（3）特有种和生态特征沿海拔梯度的变化规律。主要结论如下： 1．横断山区含特有植物2396个分类群（包括种、亚种和变种），隶属于372属90科。特有类群在372个属中的分布非常不均匀，约一半的特有类群（50.2%）集中分布在较少的属中（占总属数的6%），含特有类群的属大小差异很大，重要的大属是：马先蒿属、乌头属、杜鹃花属、翠雀属、紫堇属、虎耳草属、报春花属、小檗属、黄芪属、凤毛菊属、蚤缀属、橐吾属、龙胆属、景天属、柳属、苔草属、香茶菜属、凤仙花属、紫菀属、鼠尾草属和蝇子草属等，这些属多以横断山为分布和分化中心，为新特有成分。另外，地面芽植物和隐芽植物等占有绝对优势，而矮高位芽植物、高位芽植物、地面芽植物等占有较低的比例，反映了该特有区系的高山、亚高山植物区系特点，但又不乏与热带植物区系的渊源。与世界其它高山地区相比，该特有区系中的地面芽植物、隐芽植物和一年生植物有较高的比例。 2．草本、风力散布种子、昆虫传粉和两性花等为该特有植物区系的优势生态特征。除传粉方式和生活型间无明显的相互作用外，其它生态特征间都存在明显的正相关关系。定量化研究结果表明该特有区系特有种的传粉方式进化可塑性很小，处于保守（或原始）的进化地位。相反，种子散布方式和繁育系统的进化可塑性较大，处于衍生（或进化）的进化地位，是不同种系在历史发育过程中不同阶段的产物。生活型的进化地位在种间有较大的分异，具较小或较大可塑性的各占有一定的比例，因此生活型中既保留处于保守（或原始）的进化地位也有处于衍生（或进化）的进化地位，两种进化状态的生活型在该特有区系中并存，该特征不但是种系在进化早期决定的，同时也是不同种系在进化过程中获得的。 3． 特有种的分布不均匀，较高比例的特有种局限分布在较少的几个地区，北纬28-29°线是特有种丰富度重要的南北分界线。聚类分析结果表明其分布可以划分为3个物种聚集群：（1）北纬28-29°以北、北纬34°以南的藏东川西北物种聚集群；（2）北纬28-29°以南、北纬26°以北的藏东南—滇西北—川西南物种聚集群；和（3）北纬26°以南、北纬25°以北的滇西北物种聚集群。其中，藏东南—滇西北—川西南物种聚集群特有种丰富度最高，是横断山区特有种分布的核心区；滇西北物种聚集群特有种丰富度最低，藏东川西北物种聚集群特有种丰富度居中。藏东南—滇西北—川西南物种聚集群之所以特有种类丰富很有可能与该小区具有高的物种丰富度和落叶阔叶林、常绿/落叶针叶林的分布有密切的联系。在区域尺度上，横断山区总物种的分布中心与特有中心存在分异。尽管两者都处于北纬28-29°以南、北纬26°以北的藏东南—滇西北—川西南小区，但特有中心具有较小的分布范围，而总物种的丰富度中心分布范围较大。因此，我们推测特有分布中心不但与落叶阔叶林和常绿/落叶针叶林有密切的联系，而且也与物种丰富度有关。特有种与植被类型尤其是与常绿阔叶林和落叶阔叶林的关系研究对揭示特有现象的发生、性质和特点有一定的意义，有关研究尚需进一步开展。此外，海拔高差、区系物种丰富度、地理位置和单元面积为特有种丰富度地理分布的总体变异提供了74.7%的解释。 4．研究地区的南缘和东南缘有高比例的木本特有植物，而草本特有植物的比例相对最低，反映出该横断山区南缘的特有植物与热带植物区系的渊源关系，其成分多为一些古老的特有成分；而高比例和较高比例的草本特有植物在研究地区普遍存在，包括研究区域南、北的大部分地区，显然草本特有植物是横断山的优势特有成分。这种以草本特有植物为特征的高山、亚高山特有植物区系有别于我国其它两大特有植物分布中心。该特有中心的成因的最终解释还需要从物种形成（speciation）、灭绝（extinction）和扩散（biogeographic dispersal）——这三个直接影响一个地区物种数量变化的过程来考虑。 5．特有种丰富度沿海拔梯度呈“单峰” 变化曲线，在中海拔段达到峰值。与中国特有种、世界广布种相比，特有种的峰值最高，最适海拔分布范围最窄。特有率随海拔上升而逐渐增高，但在海拔5000-5500 m左右突然上升，在海拔6000 m左右达到最高值。说明（1）物种分布区和丰富度存在着正相关，即特有种具有小的分布区，而广布种的分布区较大；（2）特有率的线性变化规律反映了物种丰富度和特有现象之间的关系，即物种丰富度最大峰值以上海拔段物种数量减少，但特有率增加，说明了该特有区系的高海拔性质。 6．特有种沿海拔梯度表现出大小明显不同的物种聚集群，可能与横断山区的山地垂直气候及相应的植被类型有关。在2600-4600 m海拔段特有种数量最多，这可能与该海拔段分布着落叶阔叶林和常绿/落叶针叶林有密切的联系。特有植物沿海拔梯度可分为四个不同海拔段的物种聚集群：（1）200-1000 m；（2）1000-2600 m； （3）2600-4600 m；和（4）4600-6400 m。在对应海拔段依次分布着干热河谷稀树灌草丛、常绿阔叶林、落叶阔叶林和常绿/落叶针叶林、高山流石滩稀疏植丛。其中，分布在2600-4600 m海拔段的物种丰富度最高，1000-2600 m海拔段的物种丰富度次之，200-1000 m、4600-6400 m两个海拔段物种丰富度较低。 7．特有区系中占优势的生态特征包括草本、风力散布种子、虫媒传粉、两性花和克隆性等对海拔梯度的适应也呈“单峰” 变化曲线，但该主要特征与次要的生态特征（木本、动物散布种子、风媒传粉、单性花和非克隆性）相比，均具有较高的海拔峰值和较窄的最适分布范围，反映了主要生态特征对中、高海拔的适应特点。主要的生态特征与次要的生态特征并存构成了横断山区特有区系的基本生态特征。

中国近海典型海域沉积物中无机碳的形态研究

碳循环是影响地球环境中能量循环和物质流动的重要过程，而由于人类活动带来的大气CO2浓度升高对生态环境带来一系列的影响，如温室效应、海水酸化及全球灾害性气候增加等。海洋是地球上巨大的碳库，近海海域是连接陆地和海洋两大生态系统的关键环节，它接受着河流输入的大量陆源物质，并通过物理、化学和生物过程与大洋进行各种物质和能量交换。经过对海洋碳循环的多年研究，人们对碳在大洋中的迁移转化获得了比较清晰的认识，但对生物地球化学过程极为复杂的近海的研究还存在较多的不确定性。 元素的存在形态对其迁移转化有着重要影响，为研究近海不同形态无机碳，本文采用连续浸取方法，根据无机碳在沉积物中的结合强度，将无机碳分为交换态、弱碱结合态、强碱结合态、弱酸结合态和残渣态，分析了渤海湾、四十里湾附近海域、大亚湾和南海北部海域等中国典型近海海域表层及柱状沉积物中不同形态的无机碳含量，并讨论了其与各地球化学参数之间的关系，得到如下结论： 在各个研究区，沉积物中总无机碳的平均含量分别为：渤海湾6.16 mg/g，四十里湾附近海域7.51 mg/g，大亚湾3.08 mg/g，南海北部海域11.66 mg/g。渤海湾潮间带沉积物的无机碳含量普遍高于潮下带沉积物，四十里湾附近海域柱状样沉积物中无机碳含量一般随埋藏深度的增加而增加，大亚湾沉积物低的无机碳含量可能与低的陆源物质输入有关，南海北部海域表层沉积物无机碳含量分布表现出明显的近岸低深海高的分布特征，高的无机碳含量明显受生物活动影响。 渤海湾沉积物中各相无机碳的平均含量为氯化钠相0.63 mg/g、氨水相0.74 mg/g、氢氧化钠相0.28 mg/g、盐酸羟胺相3.13 mg/g、残渣相1.38 mg/g。四十里湾附近海域沉积物柱状样各形态无机碳含量为氯化钠相0.54 mg/g、氨水相0.36 mg/g、氢氧化钠相0.13 mg/g、盐酸羟胺相6.46 mg/g、残渣相0.02 mg/g。大亚湾沉积物中各相无机碳的平均含量为氯化钠相0.45 mg/g、氨水相0.50 mg/g、氢氧化钠相0.46 mg/g、盐酸羟胺相1.51 mg/g、残渣相0.16 mg/g。南海北部沉积物中各相无机碳的平均含量为氯化钠相0.52 mg/g、氨水相0.30 mg/g、氢氧化钠相0.17 mg/g、盐酸羟胺相3.79 mg/g、残渣相6.88 mg/g。在所研究的大部分近海沉积物中，盐酸羟胺相是沉积物无机碳的主要形态，只有南海北部海域表层沉积物比较特殊。 渤海湾潮下带沉积物中，碱浸取相（氢氧化钠相和氨水相）无机碳与沉积物总有机碳（TOC）和总氮（TN）之间存在较为紧密的联系；潮间带沉积物中，含水率、TOC、TN和粒度等地球化学参数与前3相及残渣相无机碳均有较紧密的联系。四十里湾附近海域柱状沉积物中，沉积物各参数对不同柱状样各形态无机碳的影响差异较大，位于芝罘岛附近的柱状样B主要受粒度影响，含水率、TOC和TN对离岸较近的柱状样D的前两相无机碳和崆峒岛北侧的柱状样E的氯化钠相无机碳有较大影响，沉积物各参数对崆峒岛南侧的柱状样C和离岸最远的柱状样S的影响相对较小。大亚湾沉积物各形态无机碳受环境影响的程度比其它海域弱。南海北部沉积物中，TOC对各形态无机碳影响较强，其中的氨水相无机碳与沉积物各参数间存在较为紧密的联系。 对比各海域的研究结果发现，不同无机碳形态之间，碱浸取相无机碳之间常存在正相关关系，氯化钠相作为比较活泼的无机碳形态，与其它各相之间的关系具有不确定性，弱酸浸取相无机碳与无机碳总量的关系较为紧密，残渣相与其它无机碳形态的关系一般较弱，说明此相无

Reciprocal chromosome painting illuminates the history of genome evolution of the domestic cat, dog and human

Domestic cats and dogs are important companion animals and model animals in biomedical research. The cat has a highly conserved karyotype, closely resembling the ancestral karyotype of mammals, while the dog has one of the most extensively rearranged mammalian karyotypes investigated so far. We have constructed the first detailed comparative chromosome map of the domestic dog and cat by reciprocal chromosome painting. Dog paints specific for the 38 autosomes and the X chromosomes delineated 68 conserved chromosomal segments in the cat, while reverse painting of cat probes onto red fox and dog chromosomes revealed 65 conserved segments. Most conserved segments on cat chromosomes also show a high degree of conservation in G-banding patterns compared with their canine counterparts. At least 47 chromosomal fissions (breaks), 25 fusions and one inversion are needed to convert the cat karyotype to that of the dog, confirming that extensive chromosome rearrangements differentiate the karyotypes of the cat and dog. Comparative analysis of the distribution patterns of conserved segments defined by dog paints on cat and human chromosomes has refined the human/cat comparative genome map and, most importantly, has revealed 15 cryptic inversions in seven large chromosomal regions of conserved synteny between humans and cats.

Dog chromosome-specific paints reveal evolutionary inter- and intrachromosomal rearrangements in the American mink and human

Forty chromosome-specific paint probes of the domestic dog (Canis familiaris, 2n = 78) were used to delineate conserved segments on metaphase chromosomes of the American mink (Mustela vison, 2n = 30) by fluorescence in situ hybridisation. Half of the 38 canine autosomal probes each painted one pair of homologous segments in a diploid mink metaphase, whereas the other 19 dog probes each painted from two to five pairs of discrete segments. In total, 38 canine autosomal paints highlighted 71 pairs of conserved segments in the mink. These painting results allow us to establish a complete comparative chromosome map between the American mink and domestic dog. This map demonstrates that extensive chromosome rearrangements differentiate the karyotypes of the dog and American mink. The 38 dog autosomes could be reconstructed from the 14 autosomes of the American mink through at least 47 fissions, 25 chromosome fusions, and six inversions. Furthermore, comparison of the current dog/mink map with the published human/dog map discloses 23 cryptic intrachromosomal rearrangements in 10 regions of conserved synteny in the human and American mink genomes and thus further refined the human/mink comparative genome map. Copyright (C) 2000 S. Karger AG, Basel.

Phylogenomic study of the subfamily Caprinae by cross-species chromosome painting with Chinese muntjac paints

Chromosomal homologies have been established between the Chinese muntjac (Muntiacus reevesi, MRE, 2n = 46) and five ovine species: wild goat (Capra aegagrus, CAE, 2n = 60), argall (Ovis ammon, OAM, 2n = 56), snow sheep (Ovis nivicola, ONI, 2n = 52), red goral (Naemorhedus cranbrooki, NCR, 2n = 56) and Sumatra serow (Capricornis sumatraensis, CSU, 2n = 48) by chromosome painting with a set of chromosome-specific probes of the Chinese muntjac. In total, twenty-two Chinese muntjac autosomal painting probes detected thirty-five homologous segments in the genome of each species. The chromosome X probe hybridized to the whole X chromosomes of all ovine species while the chromosome Y probe gave no signal. Our results demonstrate that almost all homologous segments defined by comparative painting show a high degree of conservation in G-banding patterns and that each speciation event is accompanied by specific chromosomal rearrangements. The combined analysis of our results and previous cytogenetic and molecular systematic results enables us to map the chromosomal rearrangements onto a phylogenetic tree, thus providing new insights into the karyotypic evolution of these species.

Phylogenetic study of complete cytochrome b genes in musk deer (genus Moschus) using museum samples

As an endangered animal group, musk deer (genus Moschus) are not only a great concern of wildlife conservation, but also of special interest to evolutionary studies due to long-standing arguments on the taxonomic and phylogenetic associations in this group. Using museum samples, we sequenced complete mitochondrial cytochrome b genes (1140 bp) of all suggested species of musk deer in order to reconstruct their phylogenetic history through molecular information. Our results showed that the cytochrome b gene tree is rather robust and concurred for all the algorithms employed (parsimony, maximum likelihood, and distance methods). Further, the relative rate test indicated a constant sequence substitution rate among all the species, permitting the dating of divergence events by molecular clock. According to the molecular topology, M. moschiferus branched off the earliest from a common ancestor of musk deer (about 700,000 years ago); then followed the bifurcation forming the M. berezouskii lineage and the lineage clustering M. fuscus, M. chrysogaster, and M. leucogaster (around 370,000 years before present), interestingly the most recent speciation event in musk deer happened rather recently (140,000 years ago), which might have resulted from the diversified habitats and geographic barriers in southwest China caused by gigantic movements of the Qinghai-Tibetan Plateau in history. Combining the data of current distributions, fossil records, and molecular data of this study, we suggest that the historical dispersion of musk deer might be from north to south in China. Additionally, in our further analyses involving other pecora species, musk deer was strongly supported as a monophyletic group and a valid family in Artiodactyla, closely related to Cervidae. (C) 1999 Academic Press.

Evolutionary trends of the mitochondrial lineage differentiation in species of genera Martes and Mustela

We compared partial sequences (402 bp) of the mitochondrial cytochrome b gene in 68 individuals of martens (Martes), weasels (Mustela) and their relatives from the Northern Hemisphere to identify the modes of geographic differentiation in each species. We then compared complete sequences (1140 bp) of the gene in 17 species of the family Mustelidae to know the spatial and temporal modes of speciation, constructing linearized trees with transversional substitutions for deeper lineage divergences and with transversions and transitions for younger lineages. Our data suggested that these lineages of Martes and Mustela differentiated in a stepwise fashion with five radiation stages from the generic divergences (stage I) to the intraspecific divergences (stage V), during the last 10 or 20 million years as the fossil evidence suggests. In the lineage of Martes, the first offshoots are of Martes flavigula, M. pennanti, and Gulo gulo (stage II), the second is M. foina (stage III), and the third are M. americana, M. martes, M. melampus, and M. zibellina (stage IV). The divergence of the lineages of Mustela is likely to have taken place concurrently with the radiations of the Martes. These divergence processes are attributable in part to the geographic allocation along the two continents, North America and Eurasia, as well as among peripheral insular domains, such as Taiwan and the Japanese Islands. In addition, the Eurasian continent itself was shown to have been involved in the species diversification in the martens and weasels.

Molecular phylogeny of wood mice (Apodemus, Muridae) in East Asia

Sequences of the mitochondrial cytochrome b (1140 bp) and nuclear IRBP (1152 bp) genes were used to assess the evolutionary history of Apodemus, using the complete set of Asian species. Our results indicate that speciation in Asia involved three radiations, which supports an earlier study. The initial radiation yielded A. argenteus (Japanese endemic), A. gurkha (Nepalese endemic), and the ancestral lineage of the remaining Asian species. This lineage subsequently diverged into four groups: agrarius-chevrieri (agrarius group), draco-latronum-semotus (draco group), A. peninsulae, and A. speciosus (Japanese endemic). The final step consisted of divergence within two species groups as a consequence of the geography of the Yunnan-Guizhou plateau and Taiwan. The ecological ability of two Apodemus-species to inhabit one locality via niche partitioning likely drove the second radiation and shaped the basic geographical pattern seen today: A. argenteus and A. speciosus in Japan, A. agrarius and A. peninsulae in northern China, and the A. agrarius and A. draco groups in southern China. The three radiations are estimated to have occurred 7.5, 6.6, and 1.8-0.8 Mya respectively, using the IRBP clock, based on rat-mouse divergence 12 Mya. (C) 2003 The Linnean Society of London.

Molecular phylogenetics and biogeography of Lepus in Eastern Asia based on mitochondrial DNA sequences

In spite of several classification attempts among taxa of the genus Lepus, phylogenetic relationships still remain poorly understood. Here, we present molecular genetic evidence that may resolve some of the current incongruities in the phylogeny of the leporids. The complete mitochondrial cytb, 12S genes, and parts of ND4 and control region fragments were sequenced to examine phylogenetic relationships among Chinese hare taxa and other leporids throughout the World using maximum parsimony, maximum likelihood, and Bayesian phylogenetic reconstruction approaches. Using reconstructed phylogenies, we observed that the Chinese hare is not a single monophyletic group as originally thought. Instead, the data infers that the genus Lepus is monophyletic with three unique species groups: North American, Eurasian, and African. Ancestral area analysis indicated that ancestral Lepus arose in North America and then dispersed into Eurasia via the Bering Land Bridge eventually extending to Africa. Brooks Parsimony analysis showed that dispersal events followed by subsequent speciation have occurred in other geographic areas as well and resulted in the rapid radiation and speciation of Lepus. A Bayesian relaxed molecular clock approach based on the continuous autocorrelation of evolutionary rates along branches estimated the divergence time between the three major groups within Lepus. The genus appears to have arisen approximately 10.76 MYA (+/- 0.86 MYA), with most speciation events occurring during the Pliocene epoch (5.65 +/- 1.15 MYA similar to 1.12 +/- 10.47 MYA). (c) 2005 Elsevier Inc. All rights reserved.

Adaptive Evolution of Digestive RNASE1 Genes in Leaf-Eating Monkeys Revisited: New Insights from Ten Additional Colobines

Pancreatic RNase genes implicated in the adaptation of the colobine monkeys to leaf eating have long intrigued evolutionary biologists since the identification of a duplicated RNASE1 gene with enhanced digestive efficiencies in Pygathrix nemaeus. The recent emergence of two contrasting hypotheses, that is, independent duplication and one-duplication event hypotheses, make it into focus again. Current understanding of Colobine RNASE1 gene evolution of colobine monkeys largely depends on the analyses of few colobine species. The present study with more intensive taxonomic and character sampling not only provides a clearer picture of Colobine RNASE1 gene evolution but also allows to have a more thorough understanding about the molecular basis underlying the adaptation of Colobinae to the unique leaf-feeding lifestyle. The present broader and detailed phylogenetic analyses yielded two important findings: 1) All trees based on the analyses of coding, noncoding, and both regions provided consistent evidence, indicating RNASE1 duplication occurred after Asian and African colobines speciation, that is, independent duplication hypothesis; 2) No obvious evidence of gene conversion in RNASE1 gene was found, favoring independent evolution of Colobine RNASE1 gene duplicates. The conclusion drawn from previous studies that gene conversion has played a significant role in the evolution of Colobine RNASE1 was not supported. Our selective constraint analyses also provided interesting insights, with significant evidence of positive selection detected on ancestor lineages leading to duplicated gene copies. The identification of a handful of new adaptive sites and amino acid changes that have not been characterized previously also provide a necessary foundation for further experimental investigations of RNASE1 functional evolution in Colobinae.

Large Gene Family Expansions and Adaptive Evolution for Odorant and Gustatory Receptors in the Pea Aphid, Acyrthosiphon pisum

Gaining insight into the mechanisms of chemoreception in aphids is of primary importance for both integrative studies on the evolution of host plant specialization and applied research in pest control management because aphids rely on their sense of smell

Phylogeny and zoogeography of the cyprinid genus Epalzeorhynchos Bleeker (Cyprinidae : Ostariophysi)

A total of 62 variable osteological and external characters was found among the five currently recognized species of Epalzeorhynchos. When the genera Crossocheilus and Paracrossocheilus are combined as the outgroup, only 30 of these characters can be polarized. This includes six autapomorphies. The remaining 24 polarized characters form a data matrix which yields a single, 26-step tree with a Consistency Index (CI) of 1 and a Retention Index (RI) of 1, The analysis was also performed on a combined dataset in which the 32 unpolarized characters (characters for which the combined outgroup was dimorphic) were added and coded as missing data (i.e., "?"), Analyzing this data matrix with all multistate characters ordered generates the same single most-parsimonious tree with a length of 63 steps, a CI of 0.98 and a RI of 0.97, When either Crossocheilus or Paracrossocheilus is used as the sole outgroup, the same single most-parsimonious tree is produced although the numbers of informative characters and some of the polarities differ. Evidence is presented to support the following hypotheses: (1) E, kalopterus + E, frenatus + E. bicolor + E. munensis form a monophyletic group; (2) E. frenatus + E, bicolor + E, munensis form a monophyletic group with E, kalopterus as its sister group; this speciation event is congruent with the predictions of vicariant speciation mode I; and (3) E. bicolor and E. munensis are sister groups, again congruent with vicariant speciation mode I, Evidence presented here also supports the zoogeographical hypothesis that the faunas of the Indochinese region and the Greater Sundas are more closely related to each other than either of them is to the lower Salween basin fauna and that the lower Mekong, Chao Phraya, and Mac Khlong basin faunas are more closely related to each other than any of them is to the Greater Sundas, In addition, the monophyly of Epalzeorhynchos is also preliminarily discussed by including either Paracrossocheilus or Crossocheilus in the ingroup. It is demonstrated that E. bicornis clusters with Paracrossocheilus when Paracrossocheilus is included in the ingroup. It seems likely that the taxonomic position of E. bicornis will be resolved as more fishes of the Crossocheilus group are included in future studies.

Taxonomic review of the genus Sinocrossocheilus Wu (Teleostei : Cyprinidae), with a description of four new species

All Sinocrossocheilus species, except S. microstomatus, are reviewed. Four new species, S. labiata, S. papillolabra, S. nigrovittata, and S. longibulla, are described. The genus Sinocrossocheilus differs from other genera of Cyprinidae by the last simple dorsal fin ray being unserrated and unossified, the last unbranched anal fin ray being unserrated and unossified, the 5-branched anal fin rays, the mouth gap being inferior, the rostral cap covering the lower jaw and connecting directly with the lower lip, a row of fleshy lobes on the lower jaw, and a cloudy black spot above the pectoral fin. Sinocrossocheilus labiata is small and has 22 predorsal scales; S. longibulla has a very large air bladder; S. papillolabra possesses a well-developed ventral fin and a wide band covered by fleshy papillae on the lower lip; and S. nigrovittata possesses black longitudinal stripes along the lateral line. Crossocheilus bamaensis and Crossocheilus liuchengensis are transferred to the genus Sinocrossocheilus. Sinocrossocheilus species are endemic to the central and eastern Yunnan-Guizhou Plateau of China, where river systems are anfractuous, including seasonal rivers, cave rivers, underground rivers, and streamlets between mountains. These separated rivers probably provide conditions for the allopatric speciation of the Sinocrossocheilus.

Phylogeny and zoogeography of the cyprinid hemicultrine group (Cyprinidae : Cultrinae)

Ying-Gui Dai and Jun-Xing Yang (2003) Phylogeny and zoogeography of the cyprinid hemicultrine group (Cyprinidae: Cultrinae). Zoological Studies 42(1): 73-92. The hemicultrine group consists of middle-sized cyprinids in Asia which taxonomically belong to the subfamily Cultrinae in the Cyprinidae (Cypriniformes), but there has been no convincing generic phylogenetic hypothesis proposal so far. On the basis of a morphological study of 65 specimens soaked in formalin and 14 skeletal specimens of 8 species in 6 genera within the hemicultrine group as an ingroup, a 70-character matrix was obtained. The generic phylogenetic relationships of the hemicultrine group are hypothesized with the matrix by the method of cladistic analysis. When the species Rasborinus lineatus or Cultrichthys erythropterus is used as the sole outgroup, the matrix gives the same single most-parsimonious tree of generic phylogenetic relationships within the hemicultrine group which shows that the hemicultrine group forms a monophyletic group. However, when Rasborinus lineatus is used as the sole outgroup and Cultrichthys erythropterus and Paralaubuca barroni are included in the ingroup, the hemicultrine group is validated to represent a paraphyletic group, and the hemicultrine group and the genus Paralaubuca form a monophyletic group. The tree of generic relationships and zoogeography of the monophyletic group comprising the hemicultrine group and the genus Paralaubuca suggest the following: (1) The monophyletic group comprises 2 smaller monophyletic groups: the genera Hemiculterella + Pseudohemiculter + Hainania and the genera Hemiculter + Paralaubuca + Pseudolaubuca + Toxabramis. (2) The sister groups of the monophyletic group show both overlapping and vicariant distribution patterns; therefore the generic distribution pattern of the monophyletic group maybe have resulted from both dispersal and vicariance events. (3) The monophyletic group probably originated on the Asian mainland from the Yangtze River to the Pearl River and on Hainan Island in China. (4) The monophyletic group probably originated after the Japanese Archipelago was separated from the Asian mainland at the beginning of the Quaternary Period in the Cenozoic but before Taiwan, Hainan Island, and Indonesia were completely isolated from the Asian mainland after the ice age in the Quaternary Period. (5) Speciation of the genus Hemiculter should have been the earliest, and those of the genera Paralaubuca, Pseudolaubuca, and Hainania ought to be the latest in the process of evolution of this monophyletic group. http://www.sinica.edu.tw/zool/zoolstud/42.1/73.pdf.

Genetic status of selected fish taxa in relation to conservation of genetic and species diversity in the Victoria and Kyoga Lake basins

Cichlids are known for their explosive radiation especially in the African Great Lakes marked with a high level of lake endemism. These fishes have been characterized mainly along trophic and habitat differences, by variation in morphological structures such as teeth and jaws and by differences in body shape and coloration. Cichlids are important as a microcosm of macroevolution. The explosive radiation, young evolutionary scale, and the isolation of groups characterized with high levels of endemism and presence of living fossils makes the group important for evolutionary and genetic studies. Lake Victoria region cichlids which are isolated and relatively more recent in evolution were the last to be appreciated in their diversity. Recently Ole Seehausen has found scores of rock fishes in Lake Victoria which were up to then thought to be absent from the Lake and only known to occur in Lakes Malawi and Tanganyika. Greenwood put together the species groups of Lake Victoria, and later in the early 1980's revised the classification of haplochromine species to reflect the phyletic origin and interrelationship of the various groups in Lake Victoria region. Melan Stiassny has been interested in early evolution of cichlids while the likes of Paul Fuerst and Lees Kaufman and Axel Meyer have been interested and are working to explain the speciation mechanisms responsible for the explosive radiation and evolution of cichlids. Locally S.B Wandera and his student Getrude Narnulemo are spearheading the biodiversity and taxonomic studies of cichlids in Lake Victoria region