齐口裂腹鱼鳞片发生及覆盖过程研究简

观察了实验室养殖条件下齐口裂腹鱼稚鱼鳞片的发生和覆盖过程。结果表明,稚鱼体长为30.7—32.3 mm时,鳞片最先出现在鳃盖后缘侧线处;体长为45.3—47.9 mm时,鳞片覆盖完毕,体长和日龄对鳞片覆盖均有显著影响。在鳞片覆盖过程中出现6个鳞片发生起始位置,依次是鳃盖后缘侧线处、尾柄部侧线处、臀鳍基部、腹鳍基部、背鳍基部和峡部。此外,组织切片的观察结果表明,齐口裂腹鱼鳞片发育主要经历了形态发生早期、形态发生晚期、分化早期、分化晚期和折叠期五个阶段。这些研究结果丰富了齐口裂腹鱼早期发育的生物学资料,将有助于了解其在系统学和功能形态学上的特征。     

重口裂腹鱼鳞片发育和覆盖过程研究

为探讨重口裂腹鱼(Schizothorax davidi)鳞片发育规律,采用茜素红饱和中性水溶液染色法和组织学方法观察了实验室养殖的重口裂腹鱼稚鱼鳞片发生和覆盖过程。结果显示,重口裂腹鱼鳞片开始发生和覆盖完成的时间分别为出膜后第62天和第110天。鳞片覆盖过程中,出现的6个鳞片发生的起始位置(出现时间)依次为鳃盖后缘侧线处(出膜后62天)、尾柄中部侧线处(出膜后71天)、臀鳍基部(出膜后79天)、腹鳍基部(出膜后83天)、背鳍基部前缘(出膜后91天)和峡部(出膜后104天)。组织学观察结果表明,鳞片发育主要经历了形态发生早期、形态发生晚期、分化早期、分化晚期和鳞片折叠期5个阶段。鳞被覆盖过程中,鳞被覆盖率(CR,%)与日龄(D,d)和体长(L,mm)的关系分别为:CR=-0.001 4D3+0.357 3D2-28.408 0D+712.78(拟合度判定系数R2=0.980 5,n=77,P0.000 1),CR=0.007 7L3-0.944 4L2+43.092 0L-634.35(拟合度判定系数R2=0.508 4,n=77,P0.000 1),鳞被覆盖率与日龄显著相关(r=0.984,P0.000 1),与体长的相关性较低(r=0.771,P0.000 1),这表明重口裂腹鱼鳞片发生和覆盖与日龄关系密切。这些研究结果丰富了重口裂腹鱼早期发育生物学资料,有助于了解其在系统学和功能形态学上的特征。     

伊洛瓦底江中国境内江段裂腹鱼属二新种描述及分类整理

该文对伊洛瓦底江水系的裂腹鱼属进行分类订正。发现了两种未被描记的鱼类新种,即白体裂腹鱼(Schizothorax leukussp.nov.)和奇异裂腹鱼(Schizothorax heteri sp.nov.)。白体裂腹鱼下唇完整不分叶、表面具发达乳突,下唇后缘平直呈横带形;下颌内侧角质突起甚厚,充满整个口腔,角质前缘锐利;胸鳍末端之前的峡部和腹部裸露无鳞;须长约等于眼径;背鳍末根不分枝鳍条较软,基部～1/3扩大变硬、后缘具明显锯齿;侧线鳞94～105,侧线上鳞26～34,侧线下鳞21～27;第一鳃弓外侧鳃耙16～20;体侧暗褐色,无明显黑斑。这些特征可将白体裂腹鱼与本属其他种类相区分。奇异裂腹鱼吻皮与上唇约等厚;下唇发达,分三叶,中间叶小,约与触须基部直径相当;唇后沟连续;下颌无锐利角质;胸鳍末端之前的峡部和腹部裸露无鳞;须长约等于眼径;背鳍末根不分枝鳍条扩大,为粗状的硬齿,后缘具强锯齿;背鳍起点位于腹鳍起点之后;侧线鳞89～104,侧线上鳞24～33,侧线下鳞19～29;通体浅灰色,体侧无斑纹;这些特征可将白体裂腹鱼与本属其他种类相区分。该研究否定了圆颌裂腹鱼(S.rotundimaxillaris)的有效性,澄清了墨脱裂腹鱼(S.molesworthi)、灰裂腹鱼(S.griseus)和保山裂腹鱼(S.paoshanensis)等在伊洛瓦底江水系的记录均属误订,确定该水系中国境内裂腹鱼属有效种为8种,并制定了伊洛瓦底江裂腹鱼属种检索表。     

西藏巨须裂腹鱼早期发育特征

巨须裂腹鱼(Schizothorax macropogon)隶属裂腹鱼亚科, 裂腹鱼属, 是西藏特有经济鱼类, 因过度捕捞, 其种群数量和分布面积下降, 在2009年中国红色名录评为“濒危”等级。研究通过研究巨须裂腹鱼早期发育特征, 旨在为该鱼的科学养护提供技术支撑。结果表明: 巨须裂腹鱼受精卵直径3.0—3.2 mm, 遇水开始具有微黏性, 随后脱黏, 经过准备卵裂阶段、卵裂阶段、囊胚阶段、原肠胚阶段、神经胚阶段、器官分化阶段、 孵化阶段, 在水温10℃的条件下, 经过460.67h孵化出来。初孵仔鱼体长9.9—1.1 mm, 心率48—50次/min, 鳃盖骨清晰可见, 下颌原基、尾鳍下骨原基可见。第2天鼻凹出现; 第3天肝胰脏原基出现; 第4天鳃耙、肩带原基出现; 第6天仔鱼上下颌开始张合; 第7天心血管分化结束, 仔鱼开始进入混合营养期; 第14天鳔一室和体侧色素带形成; 第26天肋骨原基出现; 第35天鳔二室出现, 卵黄囊耗尽; 第63天背鳍分化结束; 第83天臀鳍分化结束。巨须裂腹鱼胚胎具有独特的发育时序: 体节的出现先于胚孔封闭, 是对高原环境的一种适应和进化。     

东方百合鳞片繁殖小鳞茎发生的形态学观察

采用解剖学方法研究东方百合鳞片扦插繁殖中小鳞茎的组织发生过程。结果表明:小鳞茎的形态发生起源于鳞片近轴面基部的几层薄壁细胞,细胞脱分化后形成分生组织,再经过器官发生途径形成小鳞茎,属于外起源。小鳞茎发生过程可分为未分化期、启动期、生长锥形成期、小鳞片原基和根原基形成期、小鳞茎形成期。     

西藏双须叶须鱼八种年龄鉴定材料的比较研究

用微耳石、星耳石、脊椎骨、鳃盖骨、臀鳞、胸鳞、侧线鳞和背鳞等8种年龄鉴定材料识别和鉴定西藏双须叶须鱼的年龄特征并进行比较分析, 以确定适宜的年龄鉴定材料。结果显示: 臀鳞形态特化严重, 胸鳞、侧线鳞、背鳞的年轮特征不明显, 与微耳石比较的平均百分比误差(IAPE)分别为41.63%、51.26%、50.50%和51.26%, 其他4种年龄材料与微耳石比较的IAPE相差不大, 依次为: 星耳石(12.28%)、脊椎骨(15.67%)、鳃盖骨(17.81%); 低于23龄时, 微耳石鉴定的平均年龄与耳石和脊椎骨鉴定的平均年龄较为接近(P>0.05), 分别为14.39龄、13.13龄和13.20龄, 显著高于鳃盖骨和4种鳞片(P<0.05); 高于23龄时, 7种年龄鉴定材料都显著低于微耳石所鉴定的平均年龄(P<0.05)。用微耳石鉴定所得的最大年龄为49龄, 星耳石鉴定所得的最大年龄为35龄, 脊椎骨鉴定所得最大年龄为34龄, 鳃盖骨为34龄, 臀鳞为22龄, 胸鳞为19龄, 侧线鳞为16龄, 背鳞为17龄。微耳石年龄鉴定的年龄读数与体长呈极显著的对数函数关系(P<0.01)。综合分析认为, 微耳石最适宜作为双须叶须鱼的年龄鉴定材料。     

雅砻江短须裂腹鱼胚胎和卵黄囊仔鱼的形态发育

当前短须裂腹鱼(Schizothorax wangchiachii)已被列为雅砻江和金沙江的增殖放流保护鱼类,为探讨两水系的环境差异对其早期发育产生的影响,本文以雅砻江短须裂腹鱼为研究对象,通过人工授精获得受精卵,对胚胎和早期仔鱼的形态发育特征进行了观察,并与已有报道的金沙江短须裂腹鱼胚胎与仔鱼早期发育研究进行比较。研究结果显示,雅砻江短须裂腹鱼卵径(2.70±0.02)mm,较金沙江短须裂腹鱼大0.34 mm;初孵仔鱼全长(11.36±0.22)mm,比金沙江短须裂腹鱼长2.7 mm;在水温(14±1)℃时,两水系的短须裂腹鱼胚胎发育时序基本一致,但听囊等部分功能器官的发育时序存在差异;胚胎发育历时181 h,积温2 539.98 h℃,分别比金沙江短须裂腹鱼早73 h和低1 025 h℃;出膜后1~9 d,仔鱼的鳃、口、胸鳍、尾鳍、鳔、肠道等功能器官先后形成,第9天卵黄囊吸收基本完全,与金沙江短须裂腹鱼一致。比较表明,两水系短须裂腹鱼早期发育特征基本相同,但卵径大小、孵化历时、部分器官发育时序存在一定差异,可能是二者为适应环境而做出不同的选择。     

慈姑腋生小鳞片的发育及其超微结构的研究

慈姑叶腋内有许多１－２层细胞厚、无维管束的小鳞片,它们由叶鞘基部背腹面及叶腋部的表皮细胞分裂形成;小鳞片的发生与顶端分生组织无直接关系。靠近生长锥的幼叶叶腋内的小鳞片能覆盖生长锥;由于小鳞片细胞具有分泌粘液的功能,使生长锥和叶原基片于粘液的包裹之中,从而有效地防止了水流的侵袭。小鳞片进入分泌期后,细胞内高尔基体数量明显增多,并活跃地溢出囊泡;内质网膨大成囊泡状;线粒体由近质膜,且出现变形。小鳞片发     

山茶象(Chevrolat,1878)

正山茶象Curculio chinensis(Chevrolat,1878),又名油茶象甲、茶籽象甲,隶属于鞘翅目(Coleoptera)、象虫科(Curculionidae)。体长6.7-8.0 mm,体壁黑色,覆盖白色和黑褐色鳞片。前胸背板两侧基部和小盾片的白色鳞片密集,鞘翅的白色鳞片排列成不规则斑点,中间之后有1横带,腹面完全散布白毛。喙细长,雌虫喙长几乎等于体长,触角着生于喙基部1/3处,雄虫喙较短,为体长的2/3,触     

鱼鳍和鳞片色素组成的比较观察

鱼类体色观察常以鳞片为材料,鱼鳍和鳞片都是皮肤的衍生物,采用Nikon光学显微镜系统,对白鲫和红鲫鱼鳍及相邻体位鳞片的色素细胞组成、分布及形态结构等进行了比较观察。鱼鳍薄而透明,显微镜下观察发现鱼鳍从近体端到远体端在色素细胞总体分布上呈现出由密集逐渐稀疏的变化特征。白鲫背、胸、腹、臀、尾鳍五种鱼鳍中都分布有黑色素细胞、黄色素细胞和红色素细胞三种色素细胞类型。红鲫鱼鳍中则仅观察到黄色素细胞和红色素细胞两种色素细胞类型。同时不同部位鱼鳍与其基部相邻鱼鳞上层在色素细胞的组成上是一致的。在白鲫和红鲫的鳞片中均存在着丰富的虹彩细胞,但在鱼鳍中未观察到典型的虹彩细胞的分布,提示在鱼类体色发育中,虹彩母细胞可能具有与其它几种色素母细胞不同的迁移途径。     

Growth and morphological development of laboratory-reared larval and juvenile Pangasianodon hypophthalmus

The morphological development, including the fins, body proportions and pigmentation, of laboratory-reared larval and juvenile Pangasianodon hypophthalmus was described and their behavioral features were observed under rearing conditions. Body lengths (BL) of larvae and juveniles were 3.0 ± 0.2 (mean ± SD) mm just after hatching, and 12.9 ± 1.1 mm on day 13, reaching 23.4 ± 1.8 mm on day 25 after hatching. Aggregate fin ray numbers (for caudal fin, principal soft ray number) attained their full complements in specimens larger than 12.8 mm BL. Notochord flexion began in yolksac larvae on day 0 (10.5 h after hatching), with teeth buds and barbels appearing with jaw formation in yolksac flexion larvae on day 1. Melanophores on the body increased with growth, with a broad vertical band forming on the lateral line and an oblique band extending from above the pectoral fin base towards the forepart of the anal fin during the postflexion larval and juvenile stages. Body proportions became relatively constant in juveniles, except for maxillary barbel length (MBL), which continued to decrease. Yolksac flexion larvae started feeding on day 2 with the onset of intense cannibalism. Yolks were completely absorbed by day 3, and cannibalism ended by day 6. Subsequently, fish displayed a schooling behavior with growth, preferring relatively dark areas during the juvenile stage.     

Scale formation in selected western North Atlantic flatfishes

Patterns of scale formation (onset, completion and spatial pattern) were examined for five species of flatfishes in four families (Paralichthyidae: summer flounder Paralichthys dentatus, smallmouth flounder Etropus microstomus, Scophthalmidae: windowpane Scophthalmus aquosus, Pleuronectidae: winter flounder Pseudopleuronectes americanus and Soleidae: hogchoker Trinectes maculatus, to determine if the patterns are a useful indicator for the transition from the larval to the juvenile periods. In all species (except T. maculatus in which samples were limited), the ontogenetic pattern was very similar with onset of scale formation occurring on the lateral surface of the caudal peduncle, then spreading anteriorly along the presumptive lateral line, then laterally over the body, on to the head, and eventually on to the median fins. The timing of scale formation, relative to fish size, was late relative to other morphological and behavioural characters (i.e. fin ray formation, eye migration and settlement). The onset of scale formation, across all species, occurred at 9·0–27·0 mm total length (L_T), at the same approximate size as eye migration and settlement. Completion of scale formation on the body occurred at 22–54 mm L_T but completion of scale formation on the fins did not occur until 44–88 mm L_T. Thus completion of scale formation in these flatfishes is apparently the last external morphological change to occur during the larval to juvenile transition and, as a result, is not completed until approximately one third (S. aquosus and P. dentatus) to one fourth (P. americanus) or about the same time (E. microstomus and T. maculatus) as the size at first reproduction. This character may have relevance to defining the end of the larval period and the beginning of the juvenile period in flatfishes and other fishes. In addition, the pattern of scale formation may be useful in enhancing understanding of systematics, functional morphology and habitat use.     

中国爬岩鳅属鱼类一新种记述(鲤形目,平鳍鳅科)

记述了采自云南省沾益县德泽乡牛栏江水域的平鳍鳅科爬岩鳅属鱼类1新种,牛栏爬岩鳅 Beaufortia niulanensis Chen,Huang et Yang,sp.nov..其特征:背鳍分支鳍条7,腹鳍分支鳍条21,侧线鳞90～95,胸鳍起点相对于鼻孔和眼前缘之间,背鳍起点相对于腹鳍起点至其基部后缘的中点稍后,肛门位于腹鳍基后缘至臀鳍起点间的中点,腹鳍末端接近肛门,这些特征组合可以将新种与同属的其他2个相近种,即四川爬岩鳅B.szechuanensis(Fang)和中间爬岩鳅B.intermedia Tang et Wang区别开来.     

高原特有条鳅鱼类两新种在广西的发现及其动物地理学意义

描述了采自广西都安县红水河水系的条鳅亚科鱼类2个新种：丽纹云南鳅yhnnanilus pulcherrimussp．nov．在侧线长度、鳞片分布、鳍条数目、尾型、吻须长度等方面与侧纹云南鳅yunnanilus pleurotaenia(Regan,1904)最为相似,但新种独特的斑纹和上下唇的长乳突可明显与之区别,二者在一些度量特征上也有区别。黄体高原鳅Triplophysa flavicorpus sp．nov．与同分布于西江水系的南丹高原鳅T．nandanensis Lan et al．较为相似,并以下列特征组合与高原鳅属所有已知种相区别：背鳍分枝鳍条10根、臀鳍分枝鳍条6～7根、体被细鳞、侧线完全、具6条宽横斑和1条沿侧线的细纵纹、尾鳍深分又、尾鳍基具1半圆形黑斑、尾鳍上下叶各具2条黑色横斑、腹鳍末端后伸超过肛门、腋部具发达的肉质鳍瓣、上唇中央完全中断等。云南鳅属和高原鳅属均是高原特有类群,前者仅分布于云南东中部地区,后者则集中分布于青藏高原。两个新种的分布地均远离这两个属的分布中心,而且呈间断分布。通过各自相近种谱系关系分析,推测这种特殊的分布格局是通过隔域分化形成的。     

Growth and morphological development of laboratory-reared larval and juvenile snakeskin gourami Trichogaster pectoralis

Morphological development, including that of fins, labyrinth organ, body proportions, and pigmentation, in laboratory-hatched larval and juvenile snakeskin gourami Trichogaster pectoralis is described. Body lengths (BL; mean ± SD) of larvae and juveniles were 2.3 ± 0.1 mm just after hatching (day 0) and 8.2 ± 0.6 mm on day 22, reaching 14.1 ± 2.3 mm on day 48. Aggregate fin ray numbers attained their full complements in juveniles >11.8 mm BL. Preflexion larvae started feeding on day 2 following upper and lower jaw formation, the yolk being completely absorbed by day 12. Subsequently, oblong conical teeth appeared in postflexion larvae >8.2 mm BL (day 16). Melanophores on the body increased with growth, with a large dark spot developing on the lateral midline at the caudal margin of the body in flexion larvae >6.1 mm BL. Subsequently, a broad vertical dark band from the eye to the caudal peduncle developed in postflexion larvae >8.9 mm BL. Proportions of head and pre-anal lengths became constant in postflexion larvae greater than ca. 9–10 mm BL, whereas those of maximum body depth, eye diameter, and snout length failed to stabilize in fish of the size examined in this study. First soft fin ray of the pelvic fin elongated, reaching over 40% BL. The labyrinth organ differentiated in postflexion larvae >7.4 mm BL (day 22). Comparisons of larval and juvenile morphology with another anabantoid species Anabas testudineus were also made, revealing several distinct differences, particularly in the numbers of myomeres and fin rays in the dorsal/anal fins, mouth location and body shape.     

Development and evolution of lateral line placodes in amphibians. - II. Evolutionary diversification

The amphibian lateral line system develops from a series of lateral line placodes. The different phases of development from early induction, to pattern formation, differentiation, morphogenesis, and metamorphic fate were summarized in the first part of this review (Schlosser, 2002a). Here, a survey of the diversity of lateral line systems in amphibians is presented indicating that most phases of lateral line development have been subject to evolutionary changes. Several trends suggest important roles for both adaptive changes and internal constraints in amphibian lateral line evolution. Many of these trends involved the coordinated modification of different derivatives of lateral line placodes suggesting that these placodes are not only autonomous developmental modules, but also units of evolutionary variation that tend to be modified in a coherent and largely context-independent fashion.     

Development and evolution of lateral line placodes in amphibians I. Development

Lateral line placodes are specialized regions of the ectoderm that give rise to the receptor organs of the lateral line system as well as to the sensory neurons innervating them. The development of lateral line placodes has been studied in amphibians since the early 1900s. This paper reviews these older studies and tries to integrate them with more recent findings. Lateral line placodes are probably induced in a multistep process from a panplacodal area surrounding the neural plate. The time schedule of these inductive processes has begun to be unravelled, but little is known yet about their molecular basis. Subsequent pattern formation, morphogenesis and differentiation of lateral line placodes proceeds in most respects relatively autonomously: Onset and polarity of migration of lateral line primordia, the type, spacing, size and number of receptor organs formed, as well as the patterned differentiation of different cell types occur normally even in ectopic locations. Only the pathways for migration of lateral line primordia depend on external cues. Thus, lateral line placodes act as integrated and relatively context-insensitive developmental modules.