摘要
石林盲高原鳅Triplophysa shilinensis Chen et Yang,sp.nov.是在我国发现的第四种洞穴条鳅鱼类。其鉴别特征为:眼睛完全退化;体半透明;须发达,鼻瓣延长成须状;体裸露无鳞;背鳍、尾鳍分枝鳍条分别为7和14根;体和尾柄较细长。在摒弃趋同演化特征后,综合形态性状并结合地理分布资料分析的结果表明,类似于南盘江高原鳅的祖先曾广泛分布于滇东南一带,后来随着地下河的发育分别进入个旧卡房笆蕉箐溶洞和石林尾博邑溶洞。在溶洞间的地理隔离作用下,形成了与环境相适应的各自形态特点,最终分别演化成为目前的石林盲高原鳅和个旧盲高原鳅。本文还依据朱松泉的条鳅分类系统,订正了如下2个种:个旧盲高原鳅Triplophysa gejiuensis (Chu et Chen)、湘西盲高原鳅Triplophysa xiangxiensis (Yang et al.)。
On March 18, 1991, the authors collected 2 loach specimens from an underground cave near the famous Stone Forest of Yunnan. Jt is identified to be a new species, named Triplophysa shilinensis Chen et Yang, sp. nov., alluding to the type locality Stone Forest (The words 'Shi Lin=石林'in Chinese mean Stone Forest). New species and its phylogenetic relationship arc described and discussed in the following: Triplophysa shilinensis Chen ct Yang, sp. nov. (Fig. 1 )
Holotype KIZ 913001, 61.0 mmSL, collected on March 18, 1991 from an underground cave at Weiboyi village near Stone Forest, Yunnan (103?2'E 24?7'N).
Paratype KIZ 913002, 1 ex., 60.0mmSL; same data as holotype.
Morphomctric and mcristic data of the new species are listed in Table 1. Body elongated, compressed behind dorsal fin. Head and snout pointed. Eye completely degenerated. Anterior and posterior nostrils situated closely together. Nostral valve barbellike elongated. Upper jaw without a processus dentiformis. 6 barbels, very long. Caudal peduncle rather siender and compressed.
Dorsal fin origin slightly nearer to caudal fin base than to tip of snout. Tip of donsal fin extends beyond the vertical of anus. Anal fin origin slightly nearer to pelvic fin origin than to caudal fin base, tip of anal fin not reaching to caudal fin base. Pectoral fin reaches 62.8%-63.2% distance between pectoral and pelvic fin origins. Pelvic fin origin opposite to dorsal fin origin or slightly behind, tip of pelvic fin reaching 66.7%-79.7% distance between pelvic and anal fin origins and extending to or beyond anus. Anus situated in front ot anal origin. Caudal fin forked. Body naked.Lateral line complete. Intestine short without loop. Anterior chamber of airbladder enclosed in a bony capsule, and posterior chamber reduced. Body translucent without pigment. The stomach contents of the two type specimens consists of remains of insects.
The new species can be distinguished from other species of the genus Triplophysa by the following set of characters: eye completely degenerated and body without pigment; barbels very long; nostrils barbcllike elongated; body without scales; 7 brached dorsal and 14 caudal fin rays; body and caudal peduncle very slender (Table 1).
Distribution and habitat The new species has been found only from the underground cave near the Stone forest. The cave has a funnellike opening and goes vertically into ground for 109m before it meets a horizontal underground river. The current flowed about 0.3m/s, with a depth of 0.2-0.3m in which the blind loach was swimming slowly.
After reexamining the type specimens of Noemacheilus xiangxiensis Yang et al, and N. gejiuensis Chu et Chen and comparing with the new species, we found that both species should be ascribed to the genus Triplophysa for they have no processus dentiformis on upper jaw, and males have a raised tuberculate area below nares and thickened tuberculate pads on the back of pectoral fin rays. The new species is related to T. yunnanensis Yang, T. gejiuensis (Chu et Chen), T. nanpanjiangensis (Zhu et Cao) by sharing 7 branched dorsal fin rays. With exception of T. yunnanensis, the other species are devoid of scales on body and are more closely related to each other. Furthermore, T. shilinensis and T. gejiuensis are the most intimately related species by having less caudal fin rays and a more posteriorly situated dorsal fin (Table 1 ). Based on the phylogenetic relationship mentioned above, we hypothesized that after diversified from T. nanpanjiangensis, the common ancestor of T. shilinensis and T. gejiuensis migrated into different caves by current and each later formed unique characteristics in adaptation to its own environment and eventually evolved into different species.
基金
国家自然科学基金资助项目
关键词
石林
盲高原鳅
洞穴环境
分类地位
Stone Forest, New blind loach, Cave habitat, Phylogenetic relationship
