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。

Occurrence of Two New Plateau-indicator Loaches of Nemacheilinae(Balitoridae) in Guangxi with Reference to Zoogeographical Significance

Two new loaches of subfamily Nemacheilinae have been recognized on basis of collections from Hongshuihe River,a tributary of Xijiang in Du'an County,Guangxi,China.All type specimens of Yunnanilus pulcherrimus sp.nov.(Holotype:KIZ 995001,39 6 mm SL) were collected from an underground river,and had diagnosis characters:dorsal fin 3,8-9 (occasionally 3,9);anal fin 3,5-6 (occasionally 3,6);pectoral fin 1,8-10;pelvic fin 1,6-7 (occasionally 1,6);branched caudal fin rays 14-16 (occasionally 14);gill rakers 11-12 on the inner side of 1st gill arch;vertebrae (1 ex ) 4 29.The new species is closely related to Yunnanilus pleurotaenia (Regan,1904) in length of lateral line,pattern of scale coverage,count of fin rays,shape of caudal fin and length of rostral barbels,but can be distinguished from all congeners by its unique color pattern and the elongated papillae on upper and lower lips,and can be further distinguished from Y.pleurotaenia by some morphometric characters:standard length/body depth 4 3-5 6 (5 0) vs.3 9-4 9 (4 2),standard length/head length 4 4-5 1 (4 7) vs.3 7-3 9 (3 8),standard length/caudal peduncle length 5 7-7 1 (6 3) vs.7 7-9 1 (8 4),head length/snout length 2 7-3 5 (3 0) vs.2 5-2 8 (2 6),caudal peduncle length/depth 1 2-1 7 (1 4) vs.1 1-1 2 (1 1).All type specimens of Triplophysa flavicorpus sp.nov.(Holotype:KIZ 995004,76 4 mm SL) were diagnosticated by characters:dorsal fin 3,10;anal fin 3,6-7;pectoral fin 1,11;pelvic fin 1,6-7 (occasionally 1,6);branched caudal fin rays 8 8;gill rakers 5-9 on the outer side and 11-12 on the inner side of 1st gill arch;vertebrae (1 ex ) 4 34.The new triplophysid species is closely related to Triplophysa nandanensis Lan et al .1995 by dorsal fin origin at mid point of body,lateral line complete and deep forked caudal fin,and can be easily distinguished from all congeners by following characters:10 branched dorsal fin rays,6-7 branched anal fin rays,body covered by tiny scales,lateral line complete,6-7 broad vertical bars on body and 1 narrow longitudinal stripe along lateral line,caudal fin deeply forked,a large black spot on caudal fin base,2 black bars on both lobes of caudal fin,posterior tip of pelvic fin surpasses anus,a developed axillary lobe present at pelvic fin base,upper lip completely interrupted at the middle.Both genera of Yunnanilus and Triplophysa are plateaus indicator fishes.The genus of Yunnanilus is endemic to the eastern Yunnan Plateau.The genus of Triplophysa occurs mainly in Qinghai Tibet Plateau.The geographical location of the two new loach species in Guangxi are far away from the distribution centers of their genera.Their distribution patterns are obviously disjunct.A preliminary phylogenetic analysis on both new species and their relatives demonstrates that disjunct patterns might have been yielded by vicariant mode of speciations.