南盘江水系三种高原鳅的分化(鲤形目:鳅科)

DIFFERENTIATION OF THREE LOACHES OF THE GENUS TRIPLOPHYSA IN NANPAN BASIN, YUNNAN (PISCES: COBITIDAE)

南盘江是高原鳅属鱼类分布的南缘地带,目前发现有3种,其中有2个是新种。它们分别生活于河道或湖泊中。生活环境的差异导致了它们的分化。形态的分化主要表现在臀鳍和尾鳍分枝鳍条的数目以及体高、头长、尾柄等与有关部分的比值,须的发达程度、骨质鳔囊的形态构造,肛门的位置和身体斑纹等方面。

So far there are three species of the genus Triplophysa in Nanpan basin of Yunnan, China, i.e. T. macrophthalma Zhu el Guo from Nanpan River, T. fuxianensis sp. nov. from Lake Fu-xian and T. lacustris sp. nov. from Lake Xinyun. They occupy different environments in hydrology and biology that cause them to differentiate in the course of evolution. The differentiation must be expressed in morphological characters, such as the number of anal and caudal fin rays, relative ratio in the depth of body, head, length of caudal peduncle, the development of barbels, the shape and structure of bony capsule, the position of anus and colour patterns. Most of them can be reasonably explained by the theory of evofution. The descriptions of two new species are as following: Triplophysa fuxianensis sp. nov. (fig. 2)Holotype No. 873126, total length 85.6mm, standard length 73.3mm, collected in March, 1987 from Lake Fuxian (24°2'N 103°55'E), Yuman. Paratypes 8 specimens, no. 873125, 873127, 873128, 8611025-8611029; total length 69.3-99.1mm, standard length 59.2-84.0mm, collected from the same locally as holotype.Diagnosis: The new species resembles T. macrophthalma Zhu et Guo but differs from the latter in having fewer branched anal and caudal fin rays, Besides, the shape and structure of bony capsule are different.Triplophysa lacustris sp. nov. (fig. 3)Holotype No. 0.1399, total length 72.5mm, standard length 61.8mm, collected in April, 1961 from Lake Xinyun (24°20'N 102°45'E), Yunnan. Paratypes 10 Siemens, no. 01394-01396, 01400, 01401, 01404, 01411-01413; total length 62.1-68.9mm, standard length 52.1-57.7 mm, other data same as holotype.Diagnosis: The new species is similar to T. fuxianensis sp. nov. but differs from the latter in having longer barbels and more posteriorly situated anus. Besides, the shape of bony capsule are different. There is a deep notch at the median posterior portion of bony capsule in T. lacustris while in T. fuxianensis the corresponding portion is swollen backwards.