云南滇池濒危特有种滇池金线鲃繁殖初报

滇池金线鲃（Sinocyclocheilus grahami）是滇池湖泊生态系统的指示物种和特有种。因水质污染和外来物种入侵等因素的影响，该鱼类自1986年起就从湖体中消失，仅有湖周围的少数龙潭中尚保存有少量滇池金线鲃。至2007年3月初，有两次繁殖试验取得了成功。先后试验了5尾雌鱼和6尾雄鱼，获得鱼卵约1 600粒，并实施干法受精。约有1 320粒受精，平均受精率为73%。孵化出鱼苗约480尾，平均孵化率为36%。经10天饲养，约有95%以上的鱼苗存活，体长达8—12 mm。滇池金线鲃人工繁殖成功的意义有三点：能有效保护该物种免于灭绝；繁殖的鱼苗放归湖泊合适水域，将有助于恢复滇池的土著生物多样性；有助于推动当地水产养殖业从非土著鱼类养殖向土著鱼类养殖的方向转变。     

池塘养殖环境下滇池金线鲃仔稚鱼的食性转化与生长

2008年3月—2009年3月,把35 000尾滇池金线鲃(Sinocyclocheilus grahami)仔稚鱼分别饲养于3个池塘进行对比饲养研究。密度分别是：P1为208尾/m3;P2为167尾/m3;P3为41尾/m3。饲养期间采用相同的管理措施。每天数据收集采用：在仔鱼孵化后的5～16 d的每天8:00和18:00从每个育苗池中捞取5～8尾仔鱼进行测量分析。仔鱼开口30ｄ后,每月从培育池各捞取15尾,测量全长和体重。研究发现,滇池金线鲃仔鱼的开口时间为孵化后的5ｄ,混合营养期3～5 d,这与初孵的滇池金线鲃仔鱼的全长和卵黄囊较大有关。在容易造成仔鱼大量死亡的混合营养期,通过采用浆状物—轮虫—人工混合饲料的方式,大幅度提高了滇池金线鲃仔稚鱼的存活率,孵化一年后的滇池金线鲃稚鱼存活率可达82.7%。经过一周年的饲养,滇池金线鲃稚鱼的体重由(0.027±0.01) g（0.003~1.22）增长到(8.83±0.54) g（3.7~16.7）,月均增重为0.73 g;全长由(15.8±0.30) mm（11.5~20.0）增长到(91.6±1.67)mm（75.0~16.0）,全长月均增长6.32 mm。滇池金线鲃稚鱼全年全长的增长呈线性相关,y=9.82+7.05 month（R2=0.989 1）;全年体重的增长呈指数关系,y=0.0158 month2.54（R2=0.993 9）。     

云南滇池濒危特有种滇池金线鲃繁殖初报

滇池金线鲃(Sinocyclocheilus grahami)是滇池湖泊生态系统的指示物种和特有种。因水质污染和外来物种入侵等因素的影响,该鱼类自1986年起就从湖体中消失,仅有湖周围的少数龙潭中尚保存有少量滇池金线鲃。至2007年3月初,有两次繁殖试验取得了成功。先后试验了5尾雌鱼和6尾雄鱼,获得鱼卵约1600粒,并实施干法受精。约有1320粒受精,平均受精率为73%。孵化出鱼苗约480尾,平均孵化率为36%。经10天饲养,约有95%以上的鱼苗存活,体长达8-12mm。滇池金线鲃人工繁殖成功的意义有三点:能有效保护该物种免于灭绝;繁殖的鱼苗放归湖泊合适水域,将有助于恢复滇池的土著生物多样性;有助于推动当地水产养殖业从非土著鱼类养殖向土著鱼类养殖的方向转变。     

滇池金线鲃亲鱼培育、繁殖力以及卵径大小与胚胎存活率的关系

2007—2010年,对滇池金线鲃(Sinocyclocheilus grahami)进行了亲鱼培育、繁殖力和卵径(egg diameter,ED)大小的研究。滇池金线鲃的催产率、核偏位率和孵化率分别由2007年的25.2%、61.5%和30.4%到2010年的91.3%、85.2%和44.5%。四年间这3项指标均有不同程度提高,其中,催产率提高的幅度最大。提供适合滇池金线鲃营养全面的饵料可以保证亲鱼培育的最佳效果,获得高质量的鱼卵和鱼苗。滇池金线鲃绝对怀卵量与体长的关系是F=0.0004826SL3.166(R2=0.6424,P<0.05)。四年来滇池金线鲃的平均产卵量为(2118.4±899.1)粒,平均绝对怀卵量为(2402.9±881.9)粒,平均相对怀卵量为(70.4±20.8)粒。产卵量、绝对怀卵量和相对怀卵量都有随着体长增加而增加的趋势。卵的大小与胚胎存活相关,在胚胎发育的前两天,不同批次胚胎的死亡呈现一种稳定的或低的死亡率;而后5～7d不同大小的卵呈现不同的死亡率,即小的卵具有更高的死亡率;而卵径>2.0mm的胚胎死亡率趋于稳定;大的卵有更高的生存潜力,能保证仔鱼开口前继续完善身体器官的形成或发生所需要的能量。     

云南盘鮈不同地理居群的形态变异及分化

将采自中国元江、南盘江和金沙江水系的233尾云南盘鮈和短鳔盘鮈鱼类标本,按采集点地理位置就近的原则归类分为11个组,共测量了21个框架结构性状和22个常规性状。应用多变量形态度量学方法比较云南盘鮈各地理居群间的形态差异;并期望补充云南盘鮈与短鳔盘鮈的形态学鉴别特征。主成分分析结果表明,全部标本聚集在一起没有分离。差异系数分析结果表明,金沙江组内、元江组内及短鳔盘鮈与各水系间标本的差异系数均达不到亚种水平。南盘江组内,仅组7(罗平八大河)和组8(广南大里塘)标本的"腹鳍起点-背鳍起点距/体长"的差异系数大于1.28,但仅凭一个性状不足以用来区分云南盘鮈的不同地理居群;组7(罗平八大河)和组6(罗平多依河)标本的"腹鳍起点-背鳍起点距/体长"这一比例性状的差异系数大于1.28,但这一比例性状亦没有与其他性状构成一定的性状组合,不足以用来从形态上区分云南盘鮈与短鳔盘鮈。这就说明并不是所有的类群,或在不同水系分布的同一物种均会发生分化;另外,利用形态度量学未能找到进一步区分云南盘鮈与短鳔盘鮈的形态学证据,今后需要从分子生物学等方面寻找二者间新的分类学证据。     

副沙鳅属的多变量形态分析

采用多变量分析方法对副沙鳅属Parabotia的外部形态进行了主成分分析,在27个测量性状的第1、第2主成分散布图上显示,副沙鳅属的外部形态存在着3个具有明显差异的种组:即点面副沙鳅,双斑副沙鳅、武昌副沙鳅和花斑副沙鳅,漓江副沙鳅和小副沙鳅3个种组.主成分负荷值还进一步表明,6种副沙鳅属外部度量性状的差异有多元化的倾向.结合定性特征的观察确定了副沙鳅属6个种的有效性.     

美国紫踵劈蚌与三角帆蚌和褶纹冠蚌的形态比较与判别分析

描述了紫踵劈蚌(Potamilus alatus)贝壳外部和内部特征,并对紫踵劈蚌、三角帆蚌(Hyriopsis cumingii)和褶纹冠蚌(Cristaria plicata)进行了形态学比较。运用多变量形态度量学方法分析了3种淡水育珠蚌的形态差异。主成分分析构建了2个主成分,其中第一主成分的方差贡献率为66·90%,第二主成分的贡献率为33·10%,2个主成分的累计贡献率达到100%;采用逐步判别法,从11个比例性状中筛选出6个主要性状建立了3种育珠蚌的形态判别函数,其综合判别准确率达到100%。     

中国岭鳅属鱼类圆尾群的形态差异分析

对中国岭鳅属圆尾群现有3个种及采自广西环江毛南县关安村的岭鳅标本进行外部形态比较,结果表明,采自关安的岭鳅标本与无眼岭鳅在形态上有明显的差异,它与多斑岭鳅和平头岭鳅也存在一定的差异,但缺少过硬的划分指标。鉴于此,该文运用多变量形态度量学分析了关安的岭鳅标本与多斑岭鳅和平头岭鳅的形态差异,共测量了63尾标本的26个框架结构特征和20个常规特征。主成分分析结果显示,它们分别在散点图上占据明显不相重叠的区域。此结果提示,采自关安的岭鳅标本很有可能是一个隐含的岭鳅新种,但为了最终确定其分类地位,仍需解剖学和分子生物学方面的证据支持。     

濒危鱼类稀有白甲鱼沅江种群与西江种群形态度量学性状的差异性

分别以采自沅江水系142例和西江水系92例稀有白甲鱼标本为材料,采用差异系数法、方差分析法、判别分析法和主成分分析法,研究了稀有白甲鱼沅江种群、西江种群包括10个可数性状和31个比例性状等形态度量学性状的差异性.方差分析表明,2个种群之间共有6个可数性状和27个比例性状存在着显著性差异(P＜0.05).判别分析筛选出了9个对区分2个种群贡献较大的比例性状,并建立了2个种群的判别函数式.主成分分析显示,稀有白甲鱼种群鱼体沿背腹轴、头尾轴分别有16和6个比例性状表现出了明显的变化,在尾部有2个比例性状差异明显.可见2个种群之间形态度量学性状已显示了明显的分化.这可能是两个种群长期隔离,在不同水系生态环境中产生了适应性进化的结果.然而,差异系数的计算结果表明,两个种群之间形态度量学性状的差异尚未达到亚种分化的水平.     

云南红河水系金线鲃属鱼类一新种——西畴金线鲃

该文记述了采集自云南省文山州西畴县兴街镇干海子(红河水系)一洞穴的鲤科鲃亚科金线鲃属鱼类一新种,命名为西畴金线鲃(Sinocyclocheilus xichouensis Pan,Li,Yang et Chen sp.nov.)。该新种眼睛正常,背鳍末根不分枝,鳍条变粗变硬,后缘3/5具锯齿,与属内分布在邻近南盘江水系的已知种大眼金线鲃(S.macrophthalmus)、圭山金线鲃(S.guishanensis)、狭孔金线鲃(S.angustiporus)、侧条金线鲃(S.lateristritus)、丘北金线鲃(S.qiubeiensis)、滇池金线鲃(S.grahami)、曲靖金线鲃(S.qujingensis)、麻花金线鲃(S.maculatus)、紫色金线鲃(S.purpureus)及疑似红河水系易门金线鲃(S.yimenensis)相似。籍第一鳃弓外侧鳃耙9以下的特征,可与大眼金线鲃相区别;眼间距为体长的8.1%～9.9%,吻须后伸超过眼后缘,口角须后伸超过前鳃盖骨后缘,可与圭山金线鲃相区别;背鳍起点与腹鳍起点相对,体侧沿侧线无黑色横带,可与侧条金线鲃相区别;侧线鳞74～88,侧线上鳞20,侧线下鳞16,可与滇池金线鲃相区别;侧线弯曲,侧线鳞74～88,围尾柄鳞48,可与曲靖金线鲃相区别;背鳍前距为体长的47.1%～53.7%,背鳍基长为体长的12.8%～15.8%,臀鳍前距为体长的66.0%～71.0%,臀鳍长为体长的13.7%～17.1%,胸鳍前距为体长的26.0%～29.5%,尾柄长为体长的19.3%～24.7%,下颌长为体长的4.7%～7.0%,明显区别于易门金线鲃;全身被鳞,具侧线鳞,可与其分布邻近的麻花金线鲃和紫色金线鲃相区别;背鳍前鳞35～39,鳃耙6,眼间距为体长的8.1%～9.9%,可与狭孔金线鲃及丘北金线鲃相区别。     

Dry weight carbon and nitrogen content of some euphausiids from the north Atlantic Ocean and the Celtic Sea

Euphausiids were identified, measured and then dried duringa research cruise to sites in the north-eastern Atlantic Oceanand shelf waters of the Celtic Sea in late summer. The lengthsof furcilia larvae and later stages were measured in three ways,and regressions relating each pair of measures were calculatedfor different developmental stages of each species. Four hundredand ninety-three dried specimens of nine species were weighedand length–weight regressions were calculated. A subsetof 187 specimens was selected for analysis of carbon (C) andnitrogen (N) content soon after return to the laboratory. TheC and N contents of a further 122 specimens were determinedafter the specimens had been stored for 9 years. No consistentdifferences in percentage C and N content were found betweenthe two groups, indicating no systematic change during prolongedstorage in desiccators. Calyptopes of Nyctiphanes couchi containeda lower percentage of both C (mean 36.2%) and N (mean 8.6%)than later stages (means: 40.6% C, 11.0% N). Carbon contentand C:N ratios of a group of specimens of Thysanoessa longicaudata,including some juveniles, adult males and adult females, weredistinctly higher (>46% and >5.0, respectively) than thoseof the majority of specimens of the same species.     

不同保藏处理的昆虫标本DNA提取及其随机扩增多态DNA反应

实验利用CTAB法对柳二十斑叶甲Chrysomela vigintipunctata (Scopoli)、异色瓢虫Harmonia axyridis Pollas、七星瓢虫Coccinella septempunctata Linnaeus、小地老虎Agrotis ypsilon (Rottemberg)、红蜻Crocothemis servilia Drury、无齿稻蝗Oxya abentata Willemse和中华稻蝗Oxya chinensis (Thunberg)等7种昆虫进行了基因组DNA提取。从自然干燥标本、烘干标本及酒精浸泡标本获得的DNA均可用于RAPD-PCR反应,且烘干标本、酒精浸泡标本提取效果优于自然干燥标本。这种提取方法简便易行,容易掌握,且耗资小于其它分子生物学方法。     

Carbon content of some common tropical Andaman Sea copepods

Individual carbon contents of eight common copepod speciesfrom the Andaman Sea were determined. Length–carbon regressionsare presented for four calanoids (Acrocalanus gibber, Centropagesfurcatus, Temora discaudata and Euchaeta spp.), two cyclopoids(Oncaea spp. and Corycaeus spp.) and two harpacticoids (Macrosetellagracilis and Microsetella spp.). The copepod specimens wereobtained from different localities and times of the year during1996–1997. The regression coefficients are good in calanoidand cyclopoid copepods, but poor in the harpacticoids. The slopevalues range from 2.3 to 3.8 in the calanoids to 1.2 and 1.6in the harpacticoids, while the cyclopoids have slope valuesof 2.0 and 2.9. The equations derived from this study are expectedto be general characteristics, which are applicable for thecalculation of copepod biomass and production in tropical areas.     

Development of indices for nonsacrificial sexing of imposex-affected Hexaplex (Trunculariopsis) Trunculus (Gastropoda: Muricidae)

The muricid Hexaplex (Trunculariopsis) trunculus lacks externalsexual dimorphism and is highly affected by imposex, which furthercomplicates its sexual identification. In this context, theaim of this study was to develop sexual indices based on thedimensions of male and imposex-affected female penis, whichcould constitute a useful, simple and nonsacrificial tool forsexing live specimens of T. trunculus. The adoption of sexualindices consisting of penis dimensions of both sexes relativeto individual size revealed a high accuracy in the sexual identificationof sacrificed specimens (>95% correct sexing). Additionally,multivariate discriminant analysis allowed correct sexing of98.8% of the original 1053 sacrificed individuals, with accuratesexual identification being higher for males (99.5%) than forimposex-affected females (97.7%). An anaesthetization experimentwas performed to investigate the effects produced by the anaesthetic(MgCl₂) on penis measurements, to test this nonsacrificial approachand to validate the previously developed sexual indices. Theanaesthetic provoked an expected enlargement in penis dimensionsbut, despite this side effect, the sexual indices developedfor sacrificed specimens were still highly successful in sexinganaesthetized T. trunculus (generally more than 95% correctsexual identification). The practical application and some limitationsof developing and employing this kind of index for the sexualidentification of T. trunculus and other imposex-affected gastropodspecies are discussed. (Received 30 May 2005; accepted 17 January 2006)     

Identification, distribution and relative abundance of paralarval gonatid squids (Cephalopoda: Oegopsida: Gonatidae) from the Gulf of Alaska, 2001 2003

Paralarvae of the family Gonatidae were sampled in the Gulfof Alaska during spring 2001–2003. Taxonomic characterswere determined to allow identification of the specimens tospecies. The dorsal head chromatophore pattern (DHCP) was themost robust character and allowed identification to speciesfor the first time without requiring the removal and examinationof the radula. Six different DHCPs were found among the sixspecies in the study area. The 1140 specimens collected consistedof the following six species: Berryteuthis anonychus (759),Berryteuthis magister (71), Gonatopsis borealis (155), Gonatuskamtschaticus (1), Gonatus madokai (4) and Gonatus onyx (143).The specimens had a size range of 3.0–20.63 mm dorsalmantle length with the majority of specimens smaller than 10 mm.All species showed an increasing trend in abundance from theshelf (0–200 m) to the slope (200–1000 m)to the basin (>1000 m) except G. onyx in 2001 and 2002.Wide variation in distribution and abundance was found for thefour most abundant species; however, in general, B. anonychuswas most abundant and widely distributed, followed by Gonatopisborealis, Gonatus onyx and B. magister. (Received 28 April 2006; accepted 1 February 2007)     

Cephalopods in the Diet of Albacore, Thunnus alalunga, from the Adriatic Sea

The stomachs of 56 albacore (Thunnus alalunga) caught in thesouthern Adriatic Sea contained 222 cephalopods, or 29% of prey.Most cephalopod remains were from small specimens. Juvenilesand adults of Heteroteuthis dispar (61.5% of cephalopods) were morefrequently preyed upon in the `inshore' fishing area (bottomdepth: 100-700 m); early juveniles of Todarodes sagittatus (21.6%)were more abundant ` offshore' (750- 1,150 m); early juvenilesof Histioteuthis bonnellii (16.4%) were exclusive of the latterarea. The estimated overall number of cephalopods dying of predationby albacore is 6.3 x 10⁶ specimens/fishing season (two months). (Received 6 May 1998; accepted 13 July 1998)     

NUTRITION OF TRIDACHIA CRISPATA (MORCH) (SACOGLOSSA)

Autotrophic nutrition plays an important role in adult Tridachiacrispata in the western Atlantic Ocean and results from an endosymbioticassociation between the sacoglossan and the kleptoplastids ofChlorophyta. A series of living specimens 7-80 mm in length was studied inthe laboratory. After a body length of 10 mm has been attained,the parapodial lobes of the two sides meet and fuse. Microscopicexamination of faecal strings of specimens undergoing this transitionrevealed that algal remains were produced only by juvenilesless than 13 mm long. Larger specimens defaecated only rarelyand the diminutive faecal strings contained no recognizablealgal debris. This transition probably parallels the physiologicaltransition between juvenile heterotrophic nutrition and adultautotrophic nutrition. Microscopic examination of the radulae of transitional specimensshowed no diminution of the size, number or morphology of theteeth. This indicates that in an emergency heterotrophic nutritionmay be resumed. Growth rates of Tridachia were measured in the laboratory, withand without light and the provision of algal foods. Unfed animalslost weight rather rapidly in captivity, whereas those fed uponsuitable algae (Halimeda discoidea, Caulerpa verticillata, C.racemosa and Chaetomorpha sp) did not.Caulerpa sertularioideswas suitable for food for a limited time, but proved toxic afterabout a week. Of the other species tested, Caulerpa verticillatawas the least suitable, while Halimeda, Chaetomorpha and Caulerparacemosa were the best. Ironically, C. verticillata was theonly one of the algal species tested which is known to be takenin the natural diet in Floridean waters. These experiments confirmedthat heterotrophic feeding will be resumed in Tridachia if theculture-conditions do not favour autotrophic nutrition.     

Phylogeography of the Wabash pigtoe, Fusconaia flava (Rafinesque, 1820) (Bivalvia: Unionidae)

Reconstructing the phylogeographic patterns of widely distributedand common freshwater mussel species (Bivalvia: Unionidae) mayprovide insight into unionid evolution and speciation. The Wabashpigtoe, Fusconaia flava, is currently recognized as a single,polytypic species that is widely distributed and common throughoutthe Mississippi River drainage and parts of the Canadian Interior,Great Lakes and Gulf Coast drainages. Sequence analysis of themitochondrial COI gene revealed two divergent (3.43%) clades.Clade A consisted of specimens located throughout the upperand lower Mississippi River drainage and in the Red River (Canada)and Lake Erie drainages and all F. cerina specimens. All haplotypeswithin clade A differed by three (0.55%) or fewer nucleotidesubstitutions from the most widely distributed and abundanthaplotype, F1. Clade B, consisting of specimens located in thefar western portion of the species' range, may comprise an undescribedspecies. There was no evidence of genetic differentiation amongF. flava inhabiting headwater and intermediate-sized river localitiesof the Muskingum River system and large river localities ofthe nearby Ohio River. The divergence among F. flava haplotypescomprising clade A (0.18–1.10%) was similar to the divergencebetween the F. cerina haplotypes and the F. flava haplotypescomprising clade A (0–1.10%). This study illustrates theimportance of accessing genetic diversity across the distributionof a polytypic species. Additional analyses based on a combinationof morphology and genetics are needed to determine the taxonomicstatus of clade B and to strengthen our understanding of therelationship between F. flava and F. cerina. (Received 28 May 2007; accepted 13 August 2007)     

Revision of the genus Stentor Oken (Protozoa, Ciliophora) and description of S.araucanus nov. spec, from South American lakes

Stentor is a heterolrich ciliate which often forms lawn-likecovers on the bottom and/or blooms in the pelagial of lakesworldwide. The species involved in these spectacular eventswere usually either not determined or misidentified becausethe keys are outdated and incomplete. Thus, we have revisedthe nominal species described since the first major revisionby Ehrenberg (1838). Main species characteristics are the presence/absenceof symbiotic algae, the shape of the macronucleus and the colourof the cortical pigment granules. The last character mentionedmust be studied in live cells because the pigment bleaches inchemically fixed specimens. Nineteen valid species are recognizedand dichotomously keyed according to these characteristics.Twenty-seven other species and varieties, described after Ehrenberg'srevision, are synonyms or species indeterminata A new species.S.araucanus, is described from South American lakes. It is asmall, broadly trumpet-shaped Stentor with symbiotic algae,vermiform macronucleus and blue-green cortical granules. Stentoraraucanus is probably euplanktic and restricted to the southernhemisphere. Stentor auriculalus Kahl. 1932 sensu Wang (1934)is recognized as a new species, Condylostoma wangi, and transferredto the genus Condylostoma. New nomenclatural corrections: Stentorbaicalius nom. nov. (pro S.pygmaeus, preoccupied). S loricatiisnom. corr. (for S.loricata), S.ruber nom. corr. (for S.ruhra).