Glacial Effects on Sequence Divergence of Mitochondrial COII of Polyura eudamippus (Lepidoptera: Nymphalidae) in China

Sequence divergence of mitochondrial COII was analyzed in 50 specimens belonging to five subspecies of Polyura eudamippus (Lepidoptera: Nymphalidae) collected from southern China. There were nine haplotypes in the 405 bp of partial COII sequence. Distribution of the five subspecies was primarily consistent with the spatial distribution of haplotypes. The K _st statistic showed genetic differentiation among these subspecies, except between the pair of P. e. kuangtungensis and P. e. formosana, which were separated by the Taiwan Strait. This is consistent with the 10,000-year history of the Taiwan Strait, not long enough for detectable differentiation. The present distribution pattern of COII haplotypes of P. eudamippus should be shaped by the alteration of Pleistocene glaciations, and Yunnan might be the refugium of P. eudamippus in the ice age, judging from the abundant haplotypes remaining. There were two routes for P. eudamippus in the postglacial expansion, one northward to Sichuan, Chongqing, and Hubei and another eastward to the southeastern coast of mainland China and Taiwan Island. Because the haplotype of butterflies on Hainan Island (P. e. whiteheadi) was completely different from that of mainland China, it was estimated that butterflies on Hainan Island might be from the Indo-China Peninsula rather than from mainland China.     

Genetic characteristics and possible introduced origin of the paradise fish <Emphasis Type="Italic">Macropodus opercularis</Emphasis> in the Ryukyu Archipelago,Japan

It has hitherto been unknown whether the paradise fish Macropodus opercularis that inhabits the Ryukyu Archipelago, Japan, is native to the region or was introduced. This study examined the genetic identity of fish from five islands in the Ryukyu Archipelago (Okinoerabu, Okinawa, Yagaji, Kume, and Minamidaito islands) and compared it with those from Taiwan Island, mainland China, and Hainan Island. Analyses of the mtDNA control (760 bp) and cytb (660 bp) regions showed that haplotypes of specimens from the Ryukyu Archipelago were the same as or were very similar (with a 1- or 2-bp difference) to those from Taiwan. In addition, haplotypes from the Ryukyu Archipelago also showed lower genetic diversity than those from Taiwan Island, mainland China, and Hainan Island. These results suggest a high likelihood that the fish in the Ryukyu Archipelago were artificially introduced from Taiwan. However, the possibility that the fish is indigenous to the Ryukyu Archipelago cannot be completely ruled out, because some haplotypes and a clade from the Ryukyu Archipelago have not been found in the other areas. Regardless of its origin, we emphasize the importance of the conservation of the paradise fish in the Ryukyu Archipelago as an indicator of the threatened wetland environment as well as for its cultural value.     

海南岛蚯蚓物种组成及其系统发育分析

海南岛独特的地理位置和复杂的古地理事件使其成为我国生物多样性的热点地区。已有的海南岛蚯蚓资料显示, 该岛的蚯蚓区系十分特殊, 且与大陆地区蚯蚓存在扩散与迁移。然而, 当海南岛与周围大陆断开形成独立岛屿后, 海南岛蚯蚓如何为适应海南岛的环境而逐渐形成现在岛内的分布与区系, 仍然是一个值得研究和探讨的问题。因此, 本研究在海南岛全面调查和采集蚯蚓标本, 整理海南岛地区的蚯蚓物种组成及其地理分布特征, 并联合5个线粒体基因COⅠ、COⅡ、ND1、12S rRNA和16S rRNA构建海南岛蚯蚓的分子系统发育树, 推测其分化时间和祖先分布区域, 探讨海南岛蚯蚓在岛内的分化与扩散过程。研究结果表明: (1)海南岛共有蚯蚓6科9属122种, 巨蚓科蚯蚓为优势科, 且全部为环毛类蚯蚓, 其中103种为海南岛特有种。蚯蚓物种数沿海拔呈先增加后减少的趋势, 在800‒1,000 m最大; (2)海南岛环毛类蚯蚓不同水平的遗传距离与我国巨蚓科蚯蚓的遗传距离区间基本一致。物种水平上, 美丽远盲蚓(Amynthas scitulus*)与纬向远盲蚓(A. zonarius)的基因遗传距离最小。在亚种水平, 保宁腔蚓指名亚种(Metaphire magna magna)和保宁腔蚓小型亚种(M. magna minuscula)的遗传距离均接近整体的物种水平。在种群水平, 等毛远盲蚓(A. homosetus)不同种群间遗传距离均接近整体的亚种水平; (3)海南岛环毛类蚯蚓可划分为7个类群, 其祖先于68.26 Ma开始分化, 可能起源于吊罗山。在新生代, 7个类群均得到较大发展。通过对海南岛蚯蚓组成及系统发育的梳理, 不仅为我国蚯蚓物种多样性研究提供基础资料, 也为岛屿蚯蚓物种系统发育关系分析提供科学参考。     

台湾海峡两岸生物地理学现状与展望

对生物地理学的内涵、研究领域以及进展进行了简要介绍,认为近期海峡两岸生物地理学研究的目标应当集中在:末次冰期以来的海陆变迁对海峡两岸生物分布格局的影响、海峡两岸现代动植物区系的渊源、台湾最后与大陆保持陆地连接的时间与范围、东亚岛弧对台湾生物分布格局的影响以及海峡两岸生物的物种分化与生态适应性五个方面。同时认为海峡两岸现代生物分布格局关系的一种历史生物地理学解释,应当是一个在末次冰期期间存在于长江以南的大区系片断化后对海峡两岸各自不同环境适应的结果。     

中国西南地区与台湾种子植物间断分布现象

中国西南地区和台湾植物的间断分布是东亚生物地理学上一个十分有趣的研究课题。该文对种子植物进行了统计,发现有50属具有该分布式样的种对或种（包括变种和亚种）;30属呈台-琼（至粤南）-西南间断分布,而其中大多数类群的分布区在粤南-桂南-滇南,即中国热带线以南。统计结果显示,有41属被子植物在台湾和西南之间呈连续分布;有35属从台湾分布至海南（和/或华南）或至福建（和华南）。中国台湾和大陆之间类群的连续分布,以及两者植物区系的巨大相似性表明,台湾作为大陆性岛屿,与中国大陆曾经属于一个统一的植物区系。新近纪以来台湾中央山脉和中国西南至东喜马拉雅地区均经历了海拔升高的过程,形成相似的低至中、高山生境;在第四纪冰期,一些类群在这两个地区之间形成连续的分布区。后来全球气温升高,这些植物类群从低海拔向高海拔山区迁移,由于华东至华中和华南缺少高山生境,使得原来连续分布的某些类群或其祖先类群在中国西南和台湾两地之间灭绝,从而形成间断分布。同时,台湾与大陆失去陆地连接后造成分类群在台湾和西南地区的隔离分化,以及中国南端热带生境的不连续性导致热带植物属种分布区的破碎也是形成台湾和西南间断分布的重要因素。最后将西南和台湾间断分布类群归纳为3种类型：孑遗型、分化型和热带型。     

台湾岛和海南岛兰科植物区系特征比较

为探明台湾岛和海南岛兰科( Orchidaceae)植物区系特征,在充分查阅相关资料的基础上,对2个岛屿兰科植物的物种组成、生活型和分布区类型进行分析,并对这2个岛屿与大陆陆地和周边国家兰科植物的分布特征进行比较和分析。结果表明：2个岛屿的兰科植物共有146属639种,其中,台湾岛有107属446种,海南岛有96属302种。2个岛屿树兰亚科( Subfam. Epidendroideae)的属和种比例均最高;原始的拟兰亚科( Subfam. Apostasioideae)在台湾岛无分布,而在海南岛分布有2属4种。从属和种的数量看,含1种和2~5种的属比例较高,分别占台湾岛兰科植物总属数的43.9%和36.4%,占海南岛兰科植物总属数的45.8%和40.6%;且包含种数多的属的比例较低。从生活型看,2个岛屿地生兰和附生兰的比例较高,分别占台湾岛兰科植物总种数的52.7%和34.3%,占海南岛兰科植物总种数的37.1%和55.3%。从分布区类型看,台湾岛和海南岛的兰科植物分别可划分为11和10个分布区类型,且均以热带亚洲至热带大洋洲分布型属和种的比例最高,热带亚洲分布型属和种的比例也较高。从热带成分与温带成分的数量比(R/T)看,台湾岛和海南岛兰科植物属的R/T值分别为3.6和3.3,种的R/T值分别为10.9和11.9,说明2个岛屿的兰科植物均以热带成分为主,台湾岛还包含一定的温带成分。从共有属和共有种看,2个岛屿与大陆陆地的兰科植物共有属均约占各自兰科植物总属数的90.7%,其中,三地共有属有66属;台湾岛与大陆陆地的兰科植物共有种比例较低(46.2%),而海南岛与大陆陆地的兰科植物共有种比例较高(74.9%),说明2个岛屿与大陆陆地兰科植物属的同源性较高,且海南岛兰科植物的大陆性特征更明显。与周边国家相比,2个岛屿与越南的兰科植物共有种比例较高,分别占台湾岛和海南岛兰科植物总种数的33.9%和75.2%。综合分析结果显示：台湾岛和海南岛的兰科植物种类丰富,生活型齐全,且具有明显的热带性质,但台湾岛的兰科植物还表现出一定的温带性质;2个岛屿与大陆陆地兰科植物的亲缘关系较近,但台湾岛兰科植物的特有性更明显。     

海南坡鹿的起源、进化及保护

坡鹿是世界濒危物种,三个亚种分布在东南亚大陆,仅海南坡鹿种群分布在中国海南岛.2003年,国际社会的专家和学者提出了将海南坡鹿引入泰国亚种原分布区,重建已经绝灭野生种群的建议.在此种情况下,明确海南坡鹿的起源、与其它亚种间的系统发生关系、以及遗传多样性水平对有效保护坡鹿具有重要意义.本研究以线粒体DNA D-loop区490 bp基因片段为分子标记,比较分析了海南坡鹿、泰国亚种和缅甸亚种共35个样本的序列差异.我们所测的样本中,总共发现4种单倍型.所有21个海南坡鹿样品共享1种单倍型.利用最大似然法(ML)、最大简约法(MP)、邻接法(NJ)和贝叶斯法(Bayesian)构建的系统进化树表明海南坡鹿种群与泰国亚种的关系较近.但是,二者也发生一定程度的遗传分化.海南坡鹿与泰国亚种的遗传距离均值为0.026.我们推测海南坡鹿可能是在更新世冰期(69万年前)通过陆桥由东南亚大陆迁入中国海南岛.我们的结论说明海南坡鹿的遗传多样性很低,并且已独立进化很长时间.因此,我们不支持将海南坡鹿引入泰国亚种的原分布区,重建已经绝灭的野生种群的设想和建议.我们建议将海南坡鹿与泰国亚种分别作为两个独立的进化显著单元(ESUs)进行管理.     

基于线粒体控制区的云南澜沧江和海南岛主要水系宽额鳢遗传变异分析

为了解中国宽额鳢的遗传背景以更好地保护和开发利用资源,测定了云南澜沧江和海南岛南渡江、万泉河与昌化江等4个水系9个群体74尾宽额鳢线粒体控制区411 bp序列,发现52个变异位点和20个单倍型;在系统树上可分为云南、海南毛阳群体和海南其他群体等3个分支。谱系间Fst为0.786-0.672(P0.01),基因流Nm为0.153-0.244; 74.352%的变异来自谱系间,谱系间分化时间为2.070-0.350 Ma。推测海南与云南宽额鳢分化可能受云贵高原隆起和海南岛与陆地分离等地质事件影响;海南2个谱系的形成则可能是受到了五指山山脉隆起的影响。云南组群与海南组群间Fst为0.765(P0.01),基因流Nm为0.149, 70.360%的变异来自不同地理组群间,表明云南组群和海南组群间高度分化。相比同区域分布的鱼类,宽额鳢总体的单倍型多样性和核苷酸多样性均较高(Hd=0.9030.016, =0.0360.003),其中海南琼中和石壁群体的核苷酸多样性()最高均为0.008;云南勐腊群体最低为0.000;但各个地理群体均比总体的遗传多样性低,可能是后者由多个谱系叠加所致。在简约性网络图中单倍型呈非典型星状分布,中性检验为非显著负值和核苷酸不配对分析呈现多峰分布,表明宽额鳢群体历史上较为稳定,没有出现显著种群扩张。       

Phylogeographic structure of the dwarf snakehead (Channa gachua) around Gulf of Tonkin: Historical biogeography and pronounced effects of sea‐level changes

Geological events, landscape features, and climate fluctuations have shaped the distribution of genetic diversity and evolutionary history in freshwater fish, but little attention has been paid to that around the Gulf of Tonkin; therefore, we investigated the phylogeographic structure of the dwarf snakehead (Channa gachua) on Hainan Island and mainland China, as well as two populations in Vietnam. We attempted to elucidate the origins of freshwater fish in South Hainan by incorporating genetic data from DNA markers on both the mitochondrial cytochrome b gene (cyt b) and the nuclear recombination‐activating gene 1 (RAG‐1). Mitochondrial phylogenetic analysis identified two major lineages (lineages A and B), which may represent separate species. Divergence data suggested that C. gachua populations diverged between 0.516 and 2.376 myr. The divergence of the two cryptic species is congruent with sea‐level rise, which subsequently isolated Hainan from the mainland. During the Pleistocene glaciations, the entire region of the Gulf of Tonkin and the Qiongzhou Strait became part of the coastal plain of the Asian continent, which might have resulted in the current distribution patterns and dispersal routes of C. gachua populations. The formation of three sublineages in lineage A indicated that the Gulf of Tonkin was a geographical barrier between Hainan Island and mainland China but not between Vietnam and Hainan Island. The results of this study may help to elucidate the origins of freshwater fish in South Hainan and the phylogeographic structure of C. gachua.     

Invasion history of the oriental fruit fly, Bactrocera dorsalis, in the Pacific-Asia region: two main invasion routes

The oriental fruit fly, Bactrocera dorsalis, was initially recorded in Taiwan Island in 1912, and has dispersed to many areas in the Pacific-Asia region over the last century. The area of origin of the species may be confidently placed in South-East China. However, routes of range expansion to new areas and underlying population processes remain partially unclear, despite having been the subject of several studies. To explore the invasion history of this species, a partition of the cox1 gene of mitochondrial DNA was used to investigate genetic diversity, haplotype phylogeny and demographic history of 35 populations, covering China and South-East Asia and including marginal populations from Pakistan and Hawaii. Based on neighbor-joining tree analysis and the distribution of haplotypes, two main invasion routes are inferred: one from South-East China to Central China, another from South-East China to South-East Asia, with both routes probably coinciding in Central China. Populations in Taiwan Island and Hainan Island might have originated in South-East China. The marginal populations in Pakistan and Hawaii might have undergone founding events or genetic bottlenecks. Possible strategies for the control of this species are proposed based on the invasion history and reconstructed expansion routes.     

Phylogenetic analysis of chinese rhesus macaques (Macaca mulatta) based on mitochondrial control region sequences

Between one and six subspecies of Chinese rhesus macaques (Macaca mulatta) have been proposed based on morphological differences and/or their geographic distribution. In this study, a 489 base pair fragment of the mitochondrial control region was amplified from 230 DNA samples collected from rhesus macaques in the Sichuan province in Western China. The fragment was then sequenced and aligned with 208 sequences from wild rhesus macaques, sampled throughout the species' geographic range in China downloaded from GenBank. Phylogenetic analysis of the 182 unique sequences identified among these samples divided Chinese rhesus macaques into two western haplogroups (haplogroups A and B) and three older eastern haplogroups (haplogroups C, D, and E), whose differentiation probably occurred during the penultimate glacial event. During the warming after the penultimate glacial event, haplogroups A, B, and E rapidly expanded and a relatively young subhaplogroup of haplogroup E, E', limited to Southern China but shared with Vietnamese rhesus macaques, was reintroduced from Indochina during the last glacial event. One haplotype most closely related to subhaplogroup E' probably represents the isolation of Hainan Island, to where it is restricted, from the mainland by the formation of the Qiongzhou Strait approximately 8,500 years ago. The distribution of haplogroups both informs the phylogeographic history of dispersal of Chinese rhesus macaques and has implications for their suitability as animal models in biomedical research.     

海南岛中华蜜蜂遗传多样性的微卫星DNA分析

为了解海南岛中华蜜蜂Apis cerana cerana的遗传多样性和遗传结构及其与大陆种群的关系, 本研究应用10个微卫星DNA标记对海南岛11个地点627个蜂群的627头工蜂样本和大陆2个地点102个蜂群的102头工蜂样本进行了分析。结果表明： 海南岛中华蜜蜂遗传多样性较高, 单个位点检测到等位基因5～17个; 各种群平均等位基因数为4.5～7.0个, 平均杂合度为0.59～0.65。海南岛中华蜜蜂在10个位点上表现出相似遗传结构, 文昌和屯昌种群在AT101位点的等位基因频率较特殊。岛内 岛外中华蜜蜂的遗传分化系数F_ST范围为0.06～0.13; 文昌、 屯昌种群分别同海南岛内其他9个种群的F_ST（0.06～0.12）大于这9个种群间的FST（0～0.05）。海南岛中华蜜蜂同邻近大陆种群发生了明显的遗传分化; 除文昌、 屯昌种群发生中等程度的分化外, 海南岛内其他种群之间遗传分化较小。本研究结果对海南岛中华蜜蜂资源的保护和合理利用具有重要的指导意义。     

利用近似贝氏计算推论台湾海峡沿岸秋茄种群的拓殖路线

由于地理关系,台湾海峡两岸的红树植物组成具有高度的相似性,都以耐寒性较强的秋茄为优势种。中国台湾(以下简称"台湾")与大陆仅一水之隔,因此台湾的秋茄种群来源最有可能来自东南沿海种群,然而台湾南、北红树植物种群的拓殖路线以及与大陆东南沿海种群的遗传关系的研究至今仍未见报道。通过SSR分子标记,利用近似贝氏计算(Approximate Bayesian Computation)推测海峡两岸4个分布区域秋茄的起源及其拓殖路线。结果表明4个区域的种群出现明显分化,大陆东南北部种群与其他种群间分化程度最高。通过推测台湾北部种群起源可追溯到29000—48400a前,早于末次冰期时间,且台湾北部种群遗传结构与大陆东南南部种群最相近,推测它们可能共同起源于南方祖先。大陆东南沿海南北种群的溯祖时间约为15.1万年至25.2a年前,约为更新世中期末,则意味东南沿海南、北种群的遗传分化可能受到更新世后期气候变化与海侵海退的影响而出现隔离,或东南沿海南、北种群可能来自不同的起源。而台湾南部种群与台湾北部种群的相似性,表明台湾南部种群是由北部种群拓殖而来,近似贝氏计算亦支持这个假说。因而,可以推测海峡两岸秋茄的拓殖路线是从大陆东南南方种群随黑潮迁移至台湾北部,再从北部拓殖到台湾南部。利用近似贝氏计算推论台湾海峡两岸红树林种群起源及拓殖路线,为未来我国东南沿海红树林植物的生物地理研究提供参考。     

福建平潭岛海域底栖贝类物种多样性及其地理分布

海洋底栖贝类是海洋底栖无脊椎动物的重要代表。福建平潭岛地处台湾海峡西岸北部, 是中国大陆距台湾岛最近之处, 其海域内的底栖贝类区系对了解台湾海峡及其附近海域的生态环境和底栖生物地理格局具有重要意义。本文基于对2015-2018年间中山大学国土资源与环境系在平潭岛海域采集的3,346号底栖贝类标本的鉴定, 结合已发表文献整理出了平潭岛海域底栖贝类名录, 并梳理了各物种在中国近海的地理分布类型。结果显示, 本研究所采标本分属58科122属161种, 其中47种为平潭岛海域新记录。结合历史文献记录, 平潭岛海域共有底栖贝类98科244属395种。其中93.7%的种类在南海亦有分布, 82.0%的种类在东海有分布, 31.1%的种类在黄渤海有分布, 42.3%的种类在台湾岛东部海域有分布。南海-东海分布型种类占区系总种数的49.9%; 其次为南海-黄渤海分布型(27.6%)和南海-台湾海峡分布型(16.2%)。分布限于台湾海峡及其以北的种类仅占总种数的6.3%。研究结果表明, 平潭岛海域底栖贝类区系具典型的亚热带性质, 暖水性种类和广温性种类占主要优势, 与南海北部和东海大陆沿岸地区的关系密切, 与台湾岛周边海域的联系相对较弱。     

台湾海峡鱼类物种多样性研究回顾

台湾海峡位于中国福建和台湾岛之间, 其特殊的海洋环境使得其鱼类物种多样性水平较高并独具特色。本文综述了台湾海峡鱼类物种多样性研究的历程和成果。20世纪以来, 台湾海峡鱼类物种多样性的研究可以划分为早期研究时期、研究起步时期、系统调查时期和综合研究时期4个阶段, 从最初以新种描述为主的零星报道, 到大规模系统性的综合调查和研究; 目前为止, 大陆文献共记录台湾海峡鱼类1390种, 台湾地区文献共记录鱼类1525种, 总计台湾海峡鱼类1697种。这些种类多数为暖水性广布种, 鱼类区系以印度-西太平洋暖水区的印度-马来亚区和中-日亚区过渡海区种为主; 今后台湾海峡鱼类物种多样性的研究应加强两岸合作, 并充分发挥数据库应用的优势地位。     

中间黄颡鱼群体遗传变异与亲缘生物地理

通过分析81尾采自华南西部12条水系的中间黄颡鱼(Pelteobagrus intermedius)mtDNA控制区435 bp的序列,研究其群体遗传变异及亲缘生物地理格局。结果显示,中间黄颡鱼群体间的遗传分化较小,核苷酸变异只有0.54%。12条水系的群体共有7个单倍型,其中一些现已相互隔离的水系中的群体共享同一个单倍型,提示这些水系曾经有非常密切的联系。根据嵌套进化支序分析,中间黄颡鱼可能起源于峒中河、北仑河、防城河所在的广西与越南交界地区,并通过两条途径向华南沿海西部诸独立水系和海南岛扩散,在演化过程中,曾发生片断化事件,长距离建群和持续的分布区扩张。     

中国大陆与台湾画眉亚科鸟类渊源初探

中国现有画眉亚科鸟类１３１种,占世界种数（２８２种）４７％,其中有１３种为海峡两岸（大陆与台湾）共有。海峡两岸画眉类鸟类的分布有两种情况：连续性分布或间断性分布。这种既连续又间娄的分布特点,表现在来眉类鸟类在海峡两的种内及种间的差异上,同时也体现了台湾与东喜巴拉雅地区之间来眉类鸟类的亲缘关系。在地持、气候、植被环境等诸多因素历史变迁的共同影响下,形成了画眉类鸟类在台湾岛上特有的５个种及１２个亚种。     

Contrasting phylogeographical patterns between mainland and island taxa of the Pinus luchuensis complex

Species whose geographical distribution encompasses both mainland and island populations provide an ideal system for examining isolation and genetic divergence. In this study, paternally transmitted chloroplast DNA (cpDNA) and maternally transmitted mitochondrial DNA (mtDNA) were used to estimate population structure and phylogeography of Pinus luchuensis, a species found in eastern China (ssp. hwangshanensis), Taiwan (ssp. taiwanensis), and the Ryukyu Archipelago (ssp. luchuensis). Gene genealogies of both mtDNA and cpDNA reveal two major lineages. Molecular dating indicates that these lineages diverged before the colonization of P. luchuensis subspecies in Taiwan and the Ryukyu Archipelago. Both mtDNA and cpDNA show a lack of correspondence between molecular phylogeny and subspecies designation. Phylogeographical analysis suggests that paraphyly of the subspecies is the result of recent divergence rather than secondary contacts. In spite of the short divergence history of P. luchuensis on islands, the island populations show the same degree of genetic divergence as mainland populations. Low levels of genetic diversity in the mainland ssp. hwangshanensis suggest demographic bottlenecks. In contrast, the high heterogeneity of genetic composition for island populations is likely to be associated with a history of multiple colonization from the mainland. The spatial apportionment of organelle DNA polymorphisms is consistent with a pattern of stepwise colonization on island populations.     

拟平鳅头背部斑纹和下唇结构变异及其分类学意义

针对拟平鳅(Liniparhomaloptera disparis)的两个亚种(L.disparis disparis和L.disparis qiongzhongensis)现有形态分类特征的含糊,通过观察标本室保存的15条水系441尾标本,首次提出利用下唇结构类型作为拟平鳅亚种的补充形态鉴别依据,结合头背部斑纹特征,能有效地鉴别拟平鳅各地理种群和亚种,为拟平鳅的分类和鉴定提供参考依据。依据头背部斑纹差异归纳出4种类型,分别为小斑块型(云开山脉以东的7条水系及海南岛万泉河),虫蚀纹型(云开山脉以西的5条水系),混合斑纹型(海南岛的万泉河、南渡江、昌化江共3条水系),大斑块型(海南岛的昌化江)。依据下唇结构变化情况总结出3种下唇类型,分别是半圆型(云开山脉以西的5条水系),几字型(云开山脉以东的7条水系),马蹄型(海南岛的3条水系)。依据头背部斑纹特征结合下唇结构特征,对照模式标本的描述,重新定义了拟平鳅原有的两个亚种,将分布于云开山脉以东水系的种群鉴定为指名亚种,拟平鳅L.disparis disparis,其鉴别特征为:头背部斑纹为小斑块型并且下唇类型为几字型;将海南岛种群鉴定为琼中拟平鳅L.disparis qiongzhongensis,它们都具有独特的马蹄型下唇类结构,且头背部斑纹以混合斑纹型为主。重要的发现是,分布于云开山脉以西的种群与已命名的2个亚种在形态上有明显的差异,其头背部斑纹为独特的虫蚀纹型且下唇类型为半圆型。这可能是一个新亚种。分子生物学方法也许能证明云开山脉以西的种群在遗传上的独特性以及形成新亚种的可能性。云开山脉东、西两侧以及海南岛不同水系的拟平鳅的种群分化问题值得进一步探究。     

Distribution of Dacrydium in South China During the Late Quaternary

The pollen analysis of the Late Quaternary from South China, in particular, Yunnan and Guangdong provinces, made possible to restore the past distribution of Dacrydium in China. The chinese mainland flora today is totally devoid of Dacrydium. However, a single species (D. pierrei Hickel) is represented in the montane rainforests of Hainan Island (extreme south of China). The fossil pollen grains, morphologically comparable to that of D. pierrei, were discovered from the Tertiary and the Quaternary sediments in an extensive area of China. Even in the Last Interstadial of Wurm (40000–20000 Yr. B. P.), its distribution might extend to 22-24 degrees north latitude. The climatic deterioration and the environmental change during the Last Glacial (Late Wurm) had been a crucial factor when the flora of South China underwent drastic modification. It is in the same period that the present-day restriction of D. pierrei to Hainan Island took place.