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1.
洞穴鱼类:概念、多样性及研究进展   总被引:7,自引:0,他引:7  
洞穴鱼类是淡水鱼类中一个特殊的生态类群,其生活史的自然完成离不开洞穴或地下水环境。洞穴鱼类可分为典型和非典型两种类型,前者具有易辨识的特殊适应性形态结构(如眼消失、身体透明等),后者此类特征不明显。目前世界典型洞穴鱼类共记录有107种,其中鲤形目和鲇形目的种类最多,分别占49.5%和24.3%;在科级水平上以鲤科和爬鳅科最为丰富。东南亚和中南美是洞穴鱼类多样性最高的地区,有着世界上75.0%的典型洞穴鱼类。中国的洞穴鱼类具有物种多样性高、但集中出现在个别类群(如金线鲃属(Sinocyclocheilus)和高原鳅属(Triplophysa))、物种分化强烈、分布范围狭窄、种群数量小等特点。洞穴鱼类学是一门交叉科学,研究涉及系统学、生态学、生理学、保护生物学等众多学科领域,但目前研究仍多围绕演化问题展开。中国洞穴鱼类研究还处于系统分类和区系研究水平,其他有关学科的研究有待开展。  相似文献   

2.
在国家、中国科学院、云南省多项基金的资助下,由中国科学院昆明动物研究所陈银瑞和杨君兴两位研究员主持的该项研究,先后考察了我国西南地区约60个洞穴,采集到洞穴鱼类10种,标本200号。首次报道和描述了我国第一种盲鱼,发现并描记了洞穴鱼类2新属9新种。并对洞穴鱼类进行了全面、系统的研究,内容涉及洞穴鱼类的形态、分类、生态、起源和演化。基本查清了现阶段中国洞穴鱼类的种类和地理分布,阐明了洞穴鱼的形成模式和演化序列,揭示了洞穴鱼种间特化的原因及趋同演化的趋势,扩展了我国鱼类区系研究的新领域。在国内外学术刊物上发表论文、综…  相似文献   

3.
我国洞穴鱼类的研究   总被引:5,自引:0,他引:5  
张春光  赵亚辉  王丹 《生物学通报》2003,38(9):4-6,F004
简介了洞穴生物学研究的历史和现状,指出我国对洞穴生物的研究还处于起步阶段,但对洞穴鱼类研究方面做了一些比较深入的研究工作,特别对洞穴金线鳃属鱼类的研究取得了一定的研究成果。重点对金线鱼巴属鱼类的构造特点、生物学特性、特殊的物种分化过程和地理分布格局进行了介绍。  相似文献   

4.
洞穴对于生物来说是一种极端环境,却孕育了一些鲜为人知的特殊生物,洞穴鱼类就是其中的典型代表。依据是否具有洞穴适应特征,洞穴鱼类可分为典型和非典型两大类型。中国是世界上洞穴鱼类物种多样性最丰富的国家,拥有130种有效种,其中有69种为典型洞穴鱼类。受岩溶发育和气候等影响,中国绝大多数洞穴鱼类分布在广西、云南、贵州3个省、自治区。中国的洞穴鱼类面临着严峻的生存威胁,人类经济发展造成的洞穴和地下水环境退化是最主要的威胁因素。  相似文献   

5.
洞穴鱼类的研究是洞穴生物学的一个重要组成部分,在近10余年中已记述的洞穴盲鱼种数约为世界已知盲鱼种数的1/3,研究内容以形态、分类为主,也涉及生态、起源、演化及环境等。洞穴鱼类的基本特征洞穴鱼类以其特殊的生活环境,以及适应该环境的独特构造,而成为鱼类辐射进化中的一个分支。无论它们亲缘关系如何(不同的种、属、科、目),也无论它们地理隔离的远近,它们的基本特征是眼睛缩小或缺如;体无色素,呈半透明状,隐约  相似文献   

6.
广西洞穴鱼类一新种(鲤形目:鳅科)   总被引:2,自引:0,他引:2  
本文记述了采自广西河池地区的洞穴鱼类一新种,并讨论了其分类地位。透明间条鳅,新种Heminoemacheilus hyalimus sp.nov.与同属种的区别主要表现在尾鳍分枝鳍条数目较少、须较短、眼睛完全退化、头较大和尾柄较细长等方面。  相似文献   

7.
中国特有金线鲃属鱼类研究的回顾与展望(鲤形目,鲤科)   总被引:2,自引:0,他引:2  
金线鲃属鱼类是中国特有类群,几乎所有种类的生息繁衍都离不开洞穴环境,由于洞穴间的隔离作用,属内物种分化十分强烈.本文对以往有关金线鲃属的研究进行了回顾,将其研究历程分为5个不同阶段:发现期、静默期、恢复期、快速发展期和深入研究期,每个阶段都有不同的特点和代表性工作.以往的研究以分类学为主,向传统分类和系统分类两个方向开展.目前金线鲃属鱼类研究还存在一系列问题以及研究空白.未来有关的研究可在物种演化、生态学、生理学、行为学和保护生物学等多个方面深入进行.  相似文献   

8.
金线鲃属鱼类的起源及其适应演化   总被引:5,自引:0,他引:5  
根据地史和东亚地区鱼类区系演化史,推测了金线Ba属鱼类的起源时代及其与当时古地质和古气候事件的关系,认为该类群的原始祖先可能在第三纪晚期已经存在于云贵高原一带;较系统地研究了金线Ba属鱼类的洞穴适应演化趋势,表明该类群在穴居适应过程中既表现出穴居鱼类的共同演化趋势,也表现出其独特的穴居适应方式。  相似文献   

9.
中国贵州省穴居盲鳅一新种(鲤形目,爬鳅科)   总被引:1,自引:0,他引:1  
记述了采集于贵州省荔波县佳荣镇水井湾溶洞(25°28’N,108°06’E)适应洞穴环境的鳅类1新种:佳荣盲高原鳅Triplophysa jiarongensis sp.nov.。新种与之前记录的7种分布于西江水系的高原鳅(阿庐高原鳅、个旧盲高原鳅、长须盲高原鳅、巨头高原鳅、邱北盲高原鳅、石林盲高原鳅和天峨高原鳅)同属典型洞穴鱼类,都具有一系列与洞穴环境有关的适应性特征。新种与本属其它种类的区别主要为:胸鳍长,后伸达腹鳍起点;尾鳍微凹形;体表色素退化,光滑裸露无鳞;背鳍截形,起点位于腹鳍起点略后方;腹鳍后伸盖过泄殖孔;臀鳍截形;尾柄上下缘存在脂状鳍褶;背鳍分支鳍条8;臀鳍分支鳍条6;胸鳍分支鳍条11;脊椎骨总数4+34;眼完全退化,外观无痕迹;鳔前室被骨质鳔囊包裹,后室发达膨大呈游离膜质鳔。此外还介绍了其栖息地概况和部分生态学信息。  相似文献   

10.
真洞穴生物(troglobites)对洞穴环境的适应包括体色变化(因缺乏色素导致无色或白色)、视觉和听觉退化(眼退化和听觉器官退化或消失)、触觉敏锐(附肢和触角具有更多的感觉神经元、附肢显著延长等)、产卵量少和孵化率高(洞穴内可摄取的食物量少,洞穴环境条件稳定、天敌少、每个卵的营养物含量高)以及洞穴生物代谢率小,体型较大,寿命长,发育历期长等。这一系列适应性特征是真洞穴动物共有的,被称为洞穴形态共征(troglomorphicsuite),  相似文献   

11.
The Mexican tetra Astyanax mexicanus has many of the favorable attributes that have made the zebrafish a model system in developmental biology. The existence of eyed surface (surface fish) and blind cave (cavefish) dwelling forms in Astyanax also provides an attractive system for studying the evolution of developmental mechanisms. The polarity of evolutionary changes and the environmental conditions leading to the cavefish phenotype are known with certainty, and several different cavefish populations have evolved constructive and regressive changes independently. The constructive changes include enhancement of the feeding apparatus (jaws, taste buds, and teeth) and the mechanosensory system of cranial neuromasts. The homeobox gene Prox 1, which is expressed in the expanded taste buds and cranial neuromasts, is one of the genes involved in the constructive changes in sensory organ development. The regressive changes include loss of pigmentation and eye degeneration. Although adult cavefish lack functional eyes, small eye primordia are formed during embryogenesis, which later arrest in development, degenerate, and sink into the orbit. Apoptosis and lens signaling to other eye parts, such as the cornea, iris, and retina, result in the arrest of eye development and ultimate optic degeneration. Accordingly, an eye with restored cornea, iris, and retinal photoreceptor cells is formed when a surface fish lens is transplanted into a cavefish optic cup, indicating that cavefish optic tissues have conserved the ability to respond to lens signaling. Genetic analysis indicates that multiple genes regulate eye degeneration, and molecular studies suggest that Pax6 may be one of the genes controlling cavefish eye degeneration. Further studies of the Astyanax system will contribute to our understanding of the evolution of developmental mechanisms in vertebrates.  相似文献   

12.
One of the most intriguing questions in evolutionary biology is the degree to which behavior is a necessary consequence of morphology. We explore this issue by examining phototactic behavior in epigean (eyed surface-dwelling) and troglomorphic (blind cave) forms of the teleost Astyanax fasciatus whose eyes were modified during embryogenesis by removing one or both lens vesicles from the epigean form or by transplanting the lens vesicle from an epigean fish into the optic cup of a blind cave form. Lens removal results in eye degeneration and blindness in adult epigean fish, whereas lens transplantation stimulates growth of the eye, inducing the development of optic tissues in the normally eyeless adult cave fish. Photoresponsiveness was examined by placing fish in an aquarium with one half illuminated and the other half dark and scoring their presence in the illuminated or dark half. Both the eyeless epigean fish and cave fish with induced eyes are indifferent to the illumination whereas the surface forms are scotophilic, suggesting that optic development and phototactic behavior are decoupled.  相似文献   

13.
SYNOPSIS. The eye is an extraordinary organ in terms of itsdevelopment and evolution. In cave animals, the eye is sometimesreduced or eliminated as a consequence of adaptation to lifein perpetual darkness. We have used the characid teleost Astyanaxmexicanus as a model system to investigate the mechanisms ofeye degeneration during the evolution of a cave vertebrate.Eyed surface populations of Astyanax entered caves during thePleistocene, and their descendants lost their eyes and pigmentation.Astyanax populations exhibiting various degrees of eye regressionhave been reported in 29 Mexican caves. Surface populationswith characteristics of the ancestral stock still exist in thevicinity of these caves. Thus, Astyanax represents one of thefew instances in which the ancestral (surface fish) and thederived (cavefish) developmental modes are extant and availablefor comparative studies. The cavefish embryo develops an opticprimordium consisting of a lens vesicle and optic cup but therudimentary eye arrests in development and degenerates. Herewe report that eye degeneration is accompanied by extensiveapoptosis and downregulation of the Pax-6 gene in the developinglens. The results suggest that alterations in lens developmentare important factors in eye regression during cavefish evolution.  相似文献   

14.
Change in ecological conditions, as seen in surface and cave populations of Astyanax (Teleostei), has caused the divergent evolution of a large number of traits like eyes, coloration, taste, lateral line, and different kinds of behaviour like schooling, sleep or feeding posture. Because of the interfertility of surface and cave forms these fish are an exceptional object to study the morphological and genetic basis of the evolution of such complex regressive and constructive traits. Classical crossing analyses and genomic studies are contributing to growing understanding. Both kinds of traits mostly rely on multiple genetic bases and the phenotypic manifestation in the various crosses is similar. The gene effect underlying the phenotypic manifestation may exhibit an exponential increase at differing amounts in the various traits and crosses. Missing or presence of such genetic interaction helps determine whether the variability of eyes or pigmentation exhibited by Astyanax cave fish populations like Micos, is due to a more recent origin or to secondary hybridization with the surface fish. Neither crossing analysis nor QTL mapping revealed that eye reduction is pleiotropically antagonistically related to the increase of taste buds or lateral line sense. Independent inheritance of traits suggests that Astyanax cave fish are subjected to mosaic evolution.  相似文献   

15.
We have compared Pax6 expression during embryonic development in the eyed surface form (surface fish) and several different eyeless cave forms (cavefish) of the teleost Astyanax mexicanus. Despite lacking functional eyes as adults, cavefish embryos form small optic primordia, which later arrest in development and show various degrees of eye degeneration. The pattern of Pax6 mRNA expression was modified early and late during cavefish development. In early surface fish embryos, two bilateral Pax6 expression domains are present in the anterior neural plate, which extend across the midline and fuse to form the forebrain and optic primordia. In cavefish embryos, these Pax6 domains are diminished in size and remain separated, resulting in an anterior gap in Pax6 expression and presumably the formation of smaller optic primordia. The anterior gap in Pax6 expression was confirmed by double staining for Pax6 and distalless-3 mRNA, which marks the anterior margin of the neural plate and is unaltered in cavefish. Similar anterior gaps in Pax6 expression occurred in independently derived cavefish populations, suggesting that they are important in eye degeneration. Later during surface fish development, Pax6 protein is expressed in the cornea, lens, and ganglion and amacrine cells of the neural retina. Pax6 expression was gradually reduced during cavefish lens development, concomitant with lens arrest and degeneration, and was absent in the corneal epithelium, which does not differentiate in cavefish. In contrast, Pax6 expression in the retinal ganglion and amarcine cells is unmodified in cavefish, despite retarded retinal development. The results suggest that changes in Pax6 expression are involved in the evolution of cavefish eye degeneration.  相似文献   

16.
We studied the development and evolution of craniofacial features in the teleost fish, Astyanax mexicanus. This species has an eyed surface dwelling form (surface fish) and many different cave dwelling forms (cavefish) with various degrees of reduced eyes and pigmentation. The craniofacial features we examined are the tooth-bearing maxillary bones, the nasal and antorbital bones, the circumorbital bones, and the opercular bones, all of which show evolutionary modifications in different cavefish populations. Manipulations of eye formation by transplantation of the embryonic lens, by lentectomy, or by removing the optic vesicle showed that eye-dependent and -independent processes change both the surface fish and cavefish craniofacial skeletons. The size of the olfactory pits, which the nasal and antorbital bones define, and the size and positioning of the circumorbital bones were found to correlate with eye development. For the six suborbital bones (SO1-6), the relationship with the developing eye appears to be due to ossification initiated from foci in the suborbital canal of cranial neuromasts, whose patterning is also highly correlated with the presence or absence of an eye. By contrast, we found that the number of maxillary teeth, the number of SO3 bone elements, the positioning of SO4-6 with respect to the opercular bone, and the shape of the opercular bone are not dependent on eye formation and vary among different cavefish populations. The results suggest that evolution of the cavefish craniofacial skeleton is controlled by multiple developmental events, some a direct consequence of eye degeneration and others unrelated to loss of the eye.  相似文献   

17.
18.
When we teach evolution to our students, we tend to focus on “constructive” evolution, the processes which lead to the development of novel or modified structures. Most biology students are familiar with the subjects of finches’ beaks, giraffes’ necks, and hair in mammals. Of course, there is nothing inherently wrong with a constructivist approach to teaching evolution, but if it is our only focus, we may overlook the flip side of the coin. By the flip side of the coin, of course, we are referring to regressive evolution: the loss or degeneration of a trait. Regressive evolution does not often make its way into biology textbooks, but it is of great relevance nonetheless. In all likelihood, when a new trait evolves or an existing one is modified, something is sacrificed in return. In order to develop a flipper, a marine mammal must sacrifice individual digits. You may be familiar with one or more of the following familiar characters lost through regressive evolution: teeth in birds, scales in mammals, and tails in higher primates. For aficionados of cave biology like us, one of the most interesting examples of regressive evolution concerns cave fish: Why do cave fish lose their eyes?  相似文献   

19.
Quantitative aspects of regressive evolution – demonstrated by the reduction of the eyes in cave fishes According to our present understanding, the eyes of cave fishes are no longer subject to a stabilizing selection. Because of a strong mutation pressure in the destructive direction, this leads to a continual enrichment of elimination mutants and thereby to a progressive reduction of the eyes after separation of a cave population. Obviously a natural selection process does not play a significant role in the reduction of the eyes in cave fishes. Based on these findings, the degeneration process can be characterized in detail, especially concerning its course and duration.  相似文献   

20.
We investigated differentiation processes in the Neotropical fish Astyanax that represents a model system for examining adaptation to caves, including regressive evolution. In particular, we analyzed microsatellite and mitochondrial data of seven cave and seven surface populations from Mexico to test whether the evolution of the cave fish represents a case of parallel evolution. Our data revealed that Astyanax invaded northern Mexico across the Trans-Mexican Volcanic Belt at least three times and that populations of all three invasions adapted to subterranean habitats. Significant differentiation was found between the cave and surface populations. We did not observe gene flow between the strongly eye and pigment reduced old cave populations (Sabinos, Tinaja, Pachon) and the surface fish, even when syntopically occurring like in Yerbaniz cave. Little gene flow, if any, was found between cave populations, which are variable in eye and pigmentation (Micos, Chica, Caballo Moro caves), and surface fish. This suggests that the variability is due to their more recent origin rather than to hybridization. Finally, admixture of the young Chica cave fish population with nuclear markers from older cave fish demonstrates that gene flow between populations that independently colonized caves occurs. Thus, all criteria of parallel speciation are fulfilled. Moreover, the microsatellite data provide evidence that two co-occurring groups with small sunken eyes and externally visible eyes, respectively, differentiated within the partly lightened Caballo Moro karst window cave and might represent an example for incipient sympatric speciation.  相似文献   

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