光魟毒腺的显微和超微结构

为探讨魟类螫伤机理,用光镜和电镜观察了光魟的毒棘腹外侧纵沟内的毒腺的组织结构。结果表明：光魟的毒腺为复层上皮。从基底面到游离面依次为基底层、棘细胞层和嗜酸性细胞层。基底层细胞和棘层的细胞嗜碱性,棘细胞间有少量、散在分布的嗜酸性细胞;棘细胞的外层至腺上皮的游离面的嗜酸性细胞密集排列。电镜下可见基底细胞有丰富的核糖体。棘细胞内粗面内质网、高尔基复合体等较丰富。嗜酸性细胞内有电子密度低的膜包分泌颗粒;接近表面的细胞内颗粒部分融合;表层细胞核消失,胞质充满融合的颗粒,游离面侧的胞膜呈角质样增厚。腺上皮内还可见到黑色素细胞、郎格罕细胞和梅克尔细胞。提示毒腺组织内有两种类型的细胞,一类为毒液形成细胞,另一类为非毒液形成细胞。嗜酸性细胞内的电子密度低的膜包分泌颗粒成分可能是造成螫伤剧痛及全身症状的关键因素。     

鲤和鲫线粒体(mtDNA)全基因组分析

为研究鲤(Cyprinus carpio)和鲫(Carassius auratus) mtDNA上的基因分布特征,丰富鱼类mtDNA数据库。本研究通过PCR扩增和测序,获得了鲤和鲫mtDNA基因组序列,经比对分析表明,鲤和鲫的mtDNA序列全长均为16 596 bp,共有13个蛋白质编码基因、22个tRNA基因、2个rRNA基因和1个D-Loop区。鲤和鲫的mtDNA序列中(A+T)百分含量分别为57.2%和57.1%,其碱基组成均具有一定的A/T碱基偏向性。N-J系统发育树分析表明,鲤和鲫与琵琶湖鮈亲缘关系最近,与达氏深水尾魟亲缘关系最远。本研究揭示了鲤和鲫mtDNA遗传变异特征及基因分布规律,为鱼类遗传资源保护及开发利用提供了参考依据。     

南海主要珊瑚礁水域的鱼类物种多样性研究

根据2004年5–7月和2005年3–4月采用深水三重刺网在南海的羚羊礁、华光礁、银砾滩、东岛、滨湄滩、排洪滩、本固暗沙、比微暗沙、武勇暗沙、海鸠暗沙、双子群礁、中业群礁、鲎藤礁、美济礁、仁爱礁、仙宾礁、南方浅滩、棕滩、大渊滩、永署礁、南薰礁、牛轭礁、道明群礁等23座主要珊瑚礁过渡性水域进行的2个航次专业调查资料, 分析了南海主要珊瑚礁水域的鱼类种类组成和群落特征。结果表明, 在珊瑚礁水域软骨鱼类以真鲨目和鲼目的种类数占优势, 硬骨鱼类以鲈形目和鲀形目的种类数占优势。相对重要指数(IRI)大于500的鱼类定为优势种, 西沙群岛有5种, 分别为迈氏条尾魟(Taeniura meyeni)、长吻裸颊鲷(Lethrinus miniatus)、胡椒鲷(Plectorhinchus pictus)、黄斑胡椒鲷(P. flavomaculatus)和灰六鳃鲨(Hexanchus griseus); 中沙群岛有6种, 分别为黄斑胡椒鲷、迈氏条尾魟、圆燕鱼(Platax orbicularis)、密斑刺鲀(Dioson hystrix)、红裸颊鲷(Lethrinus rubrioperculatus)和胡椒鲷; 南沙群岛有3种, 分别为黑梢真鲨(Carcharhinus limbatus)、灰三齿鲨(Triaenodon obesus)和星点鲹(Caranx stellatus)。针对南海珊瑚礁水域鱼类个体大小悬殊的特点, 本文分别以个体数和生物量为基础计算该水域的Margalef丰富度指数、Shannon-Wiener多样性指数、Simpson多样性指数和Pielou均匀度指数。物种组成的区域差异分析结果表明, 各珊瑚礁水域的鱼类物种无论与南海北部陆架海域还是与南沙西南陆架区相比都有明显的差异, 而属于相同生境类型水域的鱼类物种相似性较高。     

不同渔业方式水库鱼类资源的水声学评估

采用Biosonics DT-X回声探测仪(208 kHz)在2011年的秋末冬初对大溪、沙河、金牛山3个不同渔业方式的中等营养化水库进行了水声学调查,并构建了水库中鱼类资源分布的GIS模型.结果表明： 3个水库间鱼类平均大小无显著性差异,但鱼类目标强度(TS)分布曲线表明鱼类大小分布比例并不一致,受渔业方式影响明显.大溪水库鱼类密度(平均0.0183 ind·m^-3)与沙河水库鱼类密度(平均0.0124 ind·m^-3)差异不显著,金牛山水库鱼类密度(平均0.0085 ind·m^-3)显著小于大溪水库和沙河水库,3个水库中鱼类密度水平分布与水深没有显著的相关关系.3个水库中鱼类均成群分布,对大溪水库和沙河水库调查时还发现鱼类聚群行为.3个水库的鱼类资源量分布均在下游最高,除沙河水库受赶鱼作业影响外,其他2个水库大坝前鱼类资源量分布明显偏高.基于鱼类分布GIS建模的栅格化数据、各个栅格的水面面积,对TS>-60 dB鱼类资源总量进行估算,大溪水库约为48万尾,沙河水库约为61万尾,金牛山水库约为52万尾;对TS>-40 dB的鱼类进行统计评估,大溪水库约为5.04万尾,沙河水库约为5.29万尾,金牛山水库约为9.07万尾.     

混合蛋白质体系中魟鱼和海兔肝铁蛋白释放铁的动力学研究

分别制备含有魟鱼肝铁蛋白(1iver ferritin of Dasyatis akajei,DALF)和海兔肝铁蛋白(Liver ferritin of Aplysia,ALF)的混合蛋白质体系。选用电子光谱技术和不同电子供体,研究在混合蛋白质体系中,DALF和ALF释放铁的动力学过程和规律。实验结果表明,采用Na2S2O4作为还原剂时,DALF以两相行为进行释放铁的反应;而选用抗坏血酸作为还原剂时,DALF却以一级反应动力学方式进行释放铁的反应,简化释放铁的过程。在混合蛋白质体系中且以抗坏血酸和Na2S2O4为电子供体时,ALF均以一级反应动力学过程进行释放铁的反应,认为某些蛋白质参与协助ALF释放铁反应,从而简化释放铁的过程。     

渤海南部牙鲆的食性及摄食的季节性变化

1051尾渤海南部牙鲆的胃含物分析表明,渤海南部牙鲆为捕食性(游泳生物食性)鱼类,其食物成分有30余种,以底栖虾类中的口虾蛄、鲜明鼓虾、日本鼓虾、脊尾褐虾,软体动物的日本枪乌贼及鱼类中的斑(鱼祭)、鳀鱼、黄鲫、六丝矛尾虾虎鱼及焦氏舌鳎等动物为主要食物。牙鲆除冬季外,其余时间均强烈摄食,而且其摄食的季节性变化明显:春季以鱼类(重量占80.9％)及甲壳类(18.6％)为主要食物;夏季以鱼类(83.5％)及软体动物类(13.1％)为主要食物;秋季主要摄食鱼类(87.9％);冬季则主要摄食鱼类(73.2％)及甲壳类(19.7％)。     

湖南壶瓶山国家级自然保护区山溪鱼类多样性调查与分析

2007年8月～2008年9月,作者对湖南壶瓶山国家级自然保护区山溪鱼类的物种多样性进行了调查和统计分析。共采集鱼类标本3 420尾,经分类鉴定为39种,隶属于4目11科15亚科35属。其中,草食性鱼类5种,肉食性鱼类18种,杂食性鱼类16种;四川爬岩鳅(Beaufortia szechuanensis)、鳗尾(Liobagrus anguillicauda)为湖南省鱼类新纪录。鱼类多样性指数(H′)为2.612,丰富度指数(D)为3.461,均匀度指数(J)为0.706。该区鱼类以适应山溪急流生活的21种土著鱼类为主体,占本次调查鱼类总物种数的51.2%。尖头(Phoxinus oxycephalus)和粗须白甲鱼(Onychostoma barbata)为保护区鱼类群落的优势种,相对多度指数分别为23.6%和23.4%。     

兴化湾和闽江口海域春夏季鱼类区系特征

为反映我国亚热带河口和海湾鱼类区系特点,作者于2008年春季(4月)和夏季(9月)在闽江口和兴化湾海域,采用单拖网进行鱼类学调查,并分析了两个海域鱼类种类组成和生态适应性等,进一步运用Ochilai相似性系数分析两个海域鱼类种类相似性.结果表明,在兴化湾共捕获鱼类108种,其中春季出现48种,夏季出现81种.春季竹筴鱼(Trachurus japonicus)是关键种,矛尾虾虎鱼(Chaeturichthys stigmatias)等是常见种;夏季六指马鲅(Polynemus sextarius)是关键种,赤魟(Dasyatis akajei)等是常见种.闽江口共捕获鱼类77种,其中春季出现36种,夏季出现57种.春季,凤鲚(Coilia mystus)和龙头鱼(Harpodon nehereus)是优势种,赤鼻棱鳀(Thryssa kammalensis)等是常见种;夏季凤鲚是优势种,横纹东方鲀(Takifugu oblongus)等是常见种.温度适应上,兴化湾和闽江口鱼类均以暖水种为主,分别占总种数的76.62%和75.00%,其余是暖温种;在盐度适应方面,则是沿岸种和近海种居多,分别占总种数的91.67%和87.01%.闽江口的河口种多于兴化湾.两个海域鱼类种类组成的相似度较高,而各自水体不同季节之间的相似度较低.由此推测,季节变化是导致兴化湾或闽江口鱼类种类组成变化的主要因素,盐度差异是次要因素.     

龙羊峡水库鱼类多维多样性空间分布格局

为了解龙羊峡水库鱼类多维多样性现状及空间分布格局,于2022年6月对龙羊峡的鱼类进行了调查,并结合鱼类物种出现与否、个体数和生物量3种数据类型对龙羊峡鱼类物种多样性、系统发育多样性和功能多样性现状及空间分布进行了研究。调查共采集鱼类2416尾, 94.24 kg,经鉴定有鱼类19种,隶属于4目7科17属,其中土著鱼类8种,外来鱼类11种。与历史调查相比,龙羊峡的土著鱼类减少,而外来种显著增加。基于3种数据类型计算的物种多样性、系统发育多样性和功能多样性分布结果存在差异,所以在研究鱼类生物多样性时应该结合多种数据类型对其进行综合评估。具体来看,龙羊峡物种丰富度分布呈现出库首>库尾>库中的特征,但个体数和生物量从库尾至库首逐渐减少; 3种数据类型计算出的鱼类系统发育多样性均在库中最高;基于物种出现与否和个体数两种数据类型计算的功能多样性均在库尾较高,而基于生物量数据计算的功能多样性则在库首较高。回归分析表明,龙羊峡鱼类系统发育多样性受外来物种显著影响,而物种多样性和功能多样性的变化与距大坝距离和外来种数量之间均不相关。     

海鱼体内异尖线虫生态分布初步研究

本文报道了异尖线虫在近海鱼类体内微生态分布情况。区检查２５种,８００尾近海鱼类,其中在１９种、６２９尾中２２４尾检出１型３期异尖线虫,计１５１８条,定植率为３２％,定植度为１－４３条／尾。本次发现了７种鱼、即黄鲫、孔鳐、石鲽、鲈鱼、星鳗和子,有异尖线虫幼虫定植国内还未见有文献报告。     

Dasyatis izuensis,a new stingray from the Izu Peninsula,Japan

A new dasyatidid stingray,Dasyatis izuensis sp. nov., from Japan is described on the basis of specimens collected from the Izu Peninsula. The new species is distinguished by having the following characters: diamond-shaped disc; dorsal tail keel; white ventral tail fold, its length 24.6–32.3% of disc width; short preorbital snout length, 14.1–18.7% of disc width; smooth body even in adults except for a row of 2–6 small tubercles before tail spine; and 18–20 intestinal valve turns.     

Dasyatis laosensis,a new whiptailed stingray (family Dasyatidae), from the Mekong River of Laos and Thailand

Synopsis Dasyatis laosensis, a new species, is described from the Mekong River where it forms the border between Laos and Thailand. It is the first member of the genus Dasyatis to be described as an endemic freshwater species from Southeast Asia. Bright orange color on the ventral surface of the disc and similar meristic characters indicate that it may be closely related to Dasyatis akajei, a marine species from southern Japan and China, and to Dasyatis sp. undetermined, from the West River in Guangxi, southern China.     

Description of a new ascarid species in elasmobranchs from Taiwan Strait

A new ascarid of elasmobranchs, Terranova amoyensis sp. n., is described from the intestine of the red stringray, Dasyatis akajei (Müller and Henle), from Taiwan Strait. This is the second report from this genus with a gubernaculum in fish. The new species differs from its congeners mainly in the following combination of characters: the 3 lips are unequal in size and different in shape, i.e., the subventral lips are asymmetric bilaterally and larger than the dorsal lip; the latter lip is bilaterally symmetrical. The ventriculus is spherical, and the cecum is short relative to the esophagus. Spicules are unequal in size, 1.48 mm long for the right spicule and 1.34 mm for the left spicule, or 4.3 and 3.9% of body length, respectively. Nineteen pairs of caudal sessile papillae (excluding phasmids) are present, of which 13 pairs are precloacal; pairs 14 and 15 lie close together on either side of the cloaca, composing ad-cloacal papillae (the pair near the tail end are twins). The remaining 4 pairs of postcloacal papillae form a group near the tail tip (pair 18 also twins and near the phasmids). The gubernaculum is I-shaped. The excretory pore is located on top of a coniform prominence whose location is just behind or between the bases of the 2 subventral lips. The vulva is prominent at one-third of the anterior part of the body; the distance from the vulva opening to the anterior body end is 17.4 mm (13.61-21.41), 26.8% (25.14-28.93%) of the body length.     

Steinernema akhursti sp. n. (Nematoda: Steinernematidae) from Yunnan, China

A new species of entomopathogenic nematode, herein described as Steinernema akhursti sp. n., was recovered from soil samples collected from Yunnan Province, the People's Republic of China. Both morphological and molecular data show congruently that S. akhursti sp. n. belongs to the Steinernema feltiae group. It can be separated from all described Steinernema species by the combined morphological and morphometrical characters of various stages of the nematodes. For the first generation male, the new species can be recognized by spicule length 90 +/- 4.6 microm, spicule tip blunt with an aperture on the ventral side, gubernaculum with a long and needle-shaped cuneus, and tail conoid with a prominent mucron on the tip and a concave on ventral side. For the infective juvenile, the combination of the following characters: body length 812 +/- 19 microm, distance from anterior end to excretory pore 59 +/- 1.5 microm, tail length 73 +/- 2.9 microm, E% 77 +/- 4.5, lateral field with six evenly distributed and identical ridges at the middle body portion, and tail with long and slightly constrict hyaline portion can be used to separate the new species from other nematodes. For the female, the new species is characterized by: tail conoid with a short mucron and slightly swelling anal portion and a symmetrical, slightly protruding vulva with conspicuous double-flapped epiptygma. The nematode can be separated from other described species of Steinernema by DNA sequences of either a partial 28S rDNA or the internal transcribed spacer regions of rDNA and from the closely related species S. feltiae and Steinernema oregonense by cross-breeding tests.     

两种山鹪莺的春季换羽及尾羽变化

换羽是鸟类为保证持续生存的重要过程。换羽策略与鸟类进化及对环境的适应紧密相关,研究鸟类换羽特征,对于了解鸟类的分类、系统发育、进化历史及其对环境的适应性等方面都有重要意义。2007年3月至9月,在广东肇庆市江溪村对黄腹山鹪莺(Prinia flaviventris)和纯色山鹪莺(P.inornata)的春季换羽进行了研究。通过设置雾网捕捉2种山鹪莺,对捕捉到的成体进行体重及身体量度的测量;对飞羽及尾羽进行标记:初级飞羽以翅尖的第一枚羽毛标记为"P1",次级飞羽以翅中部最外一枚标记为"S1",向内依次递增标记;尾羽以中央两根最长尾羽为"T1",分别向两侧递增标记为"T2~T5"。采用单因素方差分析(One way ANOVA)对不同月份山鹪莺的体重值进行差异性检验,对体重与月份进行Pearson相关分析,对尾羽的长度和宽度进行Pearson偏相关分析(控制变量:体长)。研究结果表明:1)两种山鹪莺换羽期为3至5月,持续时间约为60 d;2)两种山鹪莺春季换羽仅更换尾羽,换羽模式均为离心型,即中央一对尾羽最先开始替换,然后向两侧由内到外逐次更替;3)两种山鹪莺的尾羽长度和宽度同步变化,但绝大部分山鹪莺非繁殖期尾羽长度与繁殖期尾羽长度之比大于非繁殖期尾羽宽度与繁殖期尾羽宽度之比,即繁殖期尾羽相对较宽;4)两种山鹪莺换羽期间体重大致呈现下降趋势,但变化不显著(P0.05)。推测两种山鹪莺通过增加食物的摄入来抵抗换羽期和繁殖期重叠而导致的能量消耗,这可能与该地区丰富的食物资源有关,并在一定程度上体现了两种山鹪莺换羽策略对环境的适应性。     

横斑锦蛇的形态学性状初探

横斑锦蛇Euprepiophis perlacea是中国西部特有种,《中国濒危动物红皮书》极危物种,研究成果相对匮乏。本研究采用样带法和样方法在横斑锦蛇分布区内采集到标本20号,测量其鳞片特征、体长、尾长等形态学性状,结合文献资料中已有的5号标本数据,进行统计分析。结果表明,鳞片特征是有效的分类依据,尤其背鳞(19-19-17行)、左上唇鳞数(7)和右上唇鳞数(7)在所有标本中无任何变化,是鉴定该物种的最重要特征。对尾下鳞、体长、尾长、头长、头宽、头高、眼间距共7个形态学性状数据进行方差分析,性别间的差异均无统计学意义,未发现蛇类中普遍存在的两性异形现象。横斑锦蛇体色靓丽、无毒、性情温和、行动迟缓、分布区狭窄、种群数量稀少,分布区内人口密度高,人为干扰严重,急需加强科学研究、法制宣传和科普教育,以保障该物种种群延续。     

Steinernema aciari sp. n. (Nematoda: Steinernematidae), a new entomopathogenic nematode from Guangdong, China

A new species of entomopathogenic nematode, Steinernema aciari sp. n. was described. It was recovered from a soil sample collected from Haimen town, Shantou district in the eastern coast of Guangdong province, the People's Republic of China during a survey for entomopathogenic nematodes. S. aciari sp. n. belongs to the Steinernema glaseri group. It can be separated from all described Steinernema species by the combined morphological and morphometrical characters of various stages of the nematodes. For male, the new species can be recognized by spicule length (86+/-6.3 microm); spicule tip blunt with a hook-like structure; gubernaculum with a short and Y-shaped cuneus and corpus well-separated posteriorly. For infective juvenile, the combination of the following characters: body length (1113+/-68 microm), distance from anterior end to excretory pore (95+/-3.7 microm), tail length (78+/-5.2 microm), and E % (123+/-7) can be used to differentiate the new species from other nematodes. For female, the tail (conoid with a long mamillate terminus and a distinct postanal swelling) and vulva (slightly protruding from body surface with conspicuous double flapped epiptygma) shapes can be used as diagnostic characters for the new species. The new species can also be distinguished from other Steinernema species by DNA sequences of either a partial 28S rDNA or the internal transcribed spacer regions of rDNA, and from the close related species S. glaseri, Steinernema longicaudum CWL05, and Steinernema guangdongense by cross-breeding test.     

粒科线虫中国新纪录种(侧尾腺纲,垫刃目)

报道了粒科线虫的1个新纪录种:细小茎线虫Ditylenchus exilis Brzeski,1983.其鉴定特征为雌虫身体在近阴门处直或微弯;环纹宽度不规则;头连续;侧区4条侧线;口针短,锥部大约为口针长度的1/3,基球圆;中食道球梭形或微圆;后阴子宫囊为阴门处虫体直径的0.8～1.2倍;尾细,端圆,与肛阴距等长.雄虫与雌虫体形相似,交合伞钝齿形,占尾长的29%～35%.     

Length‐weight relationship of stingrays in Kuala Selangor,Malaysia

Length‐weight relationships of three sympatric species of stingrays from a coastal mudflat, Malaysia were estimated. A total of 290 individuals (150 Himantura walga, 78 Dasyatis bennetti, and 57 Dasyatis zugei) were sampled using barrier net, gill net and beam trawl. The length‐weight relationship based on disc length and width generally showed positive allometric growth (b > 3) for all species. This study reports the first findings regarding the length‐weight relationships of these stingray species in Malaysian waters.     

河南省淮河流域鳑鲏亚科5种鱼形态差异分析

为进一步从可量性状比较中华鳑鲏(Rhodeus sinensis)、越南鱊(Acheilongnathus tonkinensis)、大鳍鱊(A. macropterus)、兴凯鱊(A. chankaensis)和斑条鱊(A. taenianalis)的种间形态差异, 丰富鳑鲏亚科鱼类的形态分类特征, 研究采用多变量形态度量学方法对河南省淮河流域这5种鱼的形态进行比较分析。结果表明: 这5种鱼在体宽/体长、头长/体长、吻长/体长、尾柄长/体长、背鳍基底长/体长、腹鳍长/体长、臀鳍长/体长和头长/吻长8个比值性状上存在极显著性差异(P< 0.01), 在全长/体长、体高/体长2个比值性状上存在显著性差异(P<0.05), 这些差异主要集中在鱼体的头部、尾部和鳍等部位。主成分分析、聚类分析和判别分析显示5种鱼存在显著性形态差异, 斑条鱊与越南鱊的差异程度最大, 与大鳍鱊差异程度最小。判别分析获得的判别准确率在82.35%—100.00%变化, 可以从一定的角度区分这5种鱼。