荔波洞穴鱼类初步研究

A PRELIMINARY RESEARCH ON CAVE FISH IN LIBO COUNTY

荔波县位于贵州南部 ,地下河及洞穴发育 ,洞穴水体中鱼类亦很丰富。经过对 10 0个洞穴的考察研究 ,在地下河中及地下河出、入口处共采集到鱼类标本 2 0 0余号 ,经鉴定为 37种 ,其中真洞穴鱼类 3种 ,好洞穴鱼类 10种 ,偶洞栖鱼类 2 4种。真洞穴鱼类特化最高 ,对洞穴环境的依赖性很强 。

Libo county is situated in the southern Guizhou province, China. Karst constitutes over 70 per cent of the area. Ground rivers and karst caves are very rich, and many fish live in the groundrivers or cave water. This article is a preliminary study based on 200 specimens of fish collected from 138 karst caves of Libo county. The fish consist of 37 species and 30 genera in 10 families.These fish are divided into 3 groups according to ecology, their habitat and rudimentary or specialized degree,then 3 species of troglobites fish, 3 species of troglophiles fish and 31 species of trogloxenes fish are among the 37 species. The troglobites species are unable to survive except in caves or similar underground habitats.Their eyes,pigment on their bodies disappeared completely or greatly rudimentary,scaleless or rudimentary scales present only along the midline of their bodies;labial palps,nasal beards and proboscis beards are well developed,head is longer,parietal bone and skin is thinner and body is smaller.These characteristics indicate that the 3 species belong to greatly specialized cave fish. They are fully dependent on cave water environment,such as darkness, homoiothern,and pollution. For exmple, Nemacheilus Liboensis,Oreonectes anophthalmus,and sinocyclocheilus longibarbatus . The troglophiles species which are facultative cavenicoles.They are found living permanently,and successfully completing their life cycles in caves;but they also live in suitable epigean or endogean habitats.They are Sinocrossocheilus macrolepis, Sinocrossocheilus angustiporus, Sinocrossocheilus multipunctatus Sinocrossocheilus robustus,Garra orientalis, and Macropodus opercularis . Their eyes appear,but visual purpleis is fail, and photonasty is weak;the pigment on their bodies is rudimentary,head, skin and body is all normal.These characteristics indicate that the 10 species are midspecialized cave fish.They are dependent on cave water environment,such as mineral consistency or pH value. The trogloxenes species which occur in caves but do not complete their whole life cycle there.There can be subdivided into accidental and habitual trogloxenes.Their bodies and morphology are less specialized than those in outer cave water,and they are also independent on cave environment, e.g. Silurus gilberti, parasilurus asotus, crossocheilus bamaensis ,etc..