三峡库区的淡水贝类

ON THE FRESHWATER MOLLUSCS IN THE AREA OF SANXIA RESERVOIR

1985—1986年作者等人对三峡库区及其邻近地区的人畜寄生虫中间宿主——淡水贝类进行了调查。共采获淡水贝类49种,隶属2纲,8科20属,其中16种为传播疾病的媒介贝类,有10个新种,文中对新种进行详细的叙述。调查地区在动物地理区划归属东洋界,华中区。该区东洋界山区型种类丰富,其中以拟钉螺属的种类为优势种群,占种类总数的45.7％。

Fourty nine species of freshwater molluscs from the area of Sanxia Reservoir and nearby are recorded in this paper. These species belong to 10 genera, 8 families, 2 classes, 10 of which are considered to be new to science. All type specimens are preserved in the Institute of Zoology, Academia Sinica.I. Tricula microcosta sp. nov. (fig. 1-3)Shell minute, long-conical. Whorl 6.5 increasing slowly and regularly in size, inflated and arched in shape. Apex obtuse. Surface with fine spiral ridges. Aperture enlarged, ovate, about 1/3 of the length of shell. Radula formula:(3)2-2(3)/2-1-2;4-1-4;11;0,Holotype (SC 688706) length 3.2 mm, breadth 1.45 mm; length of aperture 1.1 mm, breadth of aperture 0.9mm. Paratypes (10 specimens): length 2.60-3.20mm, breadth 1.10-1.50mm; length of aperture 1.00-1.10mm, breadth of aperture 0.80-1.00 mm. Collected from Pengshui (29°3'N, 108°2'E), Sichuan Province, on June 9th, 1986.The species is different from T humida in the fine ridge on the surface and the radula formula. 2. Tricula zonata sp. nov. (fig. 4-6)Shell small, broad-conical. Whorl 5 - 6, only 4- 5 visible for apex eroded. Below every suture a bond parallel to it, with the color same to that of the surface. With an obvious triangular cut on the jointure of inner lip and outer lip at the upper part of the aperture. Radula formula:3-3/3-1-3; 3-1-4; 10-13; 3.Holotype (SC 868707) length 3.6mm, breadth 1.65mm; length of aperture 1.5mm, breadth of aperture 1.15mm. Paratypes (6 apecimens): length 3.50 - 3.80mm, breadth 1.70 -1.90 mm; length of aperture 1.40 - 1.70 mm, breadth of aperture 1.10 - 1.30 mm. Collected from Xiushan (28°5'N, 109°E), Sichuan Privince, on June 20th, 1986.The species is similar to T. fujianensis, but the former has a bond parallel to suture, and a triangular cut at the upper part of aperture. The radula formula is different.3. Tricula costata sp. nov. (fig. 7)Shell somewhat large, long-conical. Whorl 7 - 7.5. Body whorl inflated, more than 1/2 of the shell length. Fine vertical ridges alternating with broad ones seen on every whorl. An oblique angle formed when inner lip and outer lip meets at the upper part of aperture.Holotype (SC 868708) length 4-15 mm. breadth 1.70mm; length of aperture 1.20mm, breadth of aperture 1.15mm. Paratypes (10 specimens): length 3.90 - 4.30mm, breadth 1.70 -2.00mm; length of aperture 1.20 - 1.50mm, breadth of aperture 1.10 - 1.30mm. Collected from Xiushan (28°5'N, 109°E), Sichuan Province, on June 22nd, 1986.The species is similar to T. humida, but differs from the latter in fine vertical ridges alternating with thick ones on whorls, and in shape of aperture.4. Tricula cylindrica sp. nov. (fig. 8)Shell rather small, somewhat in a shape of cylinder. Whorl 6. Body whorl long, not inflated, about 1/2 the length of shell. Aperture obliquely-ovate, at the upper part of that curved when inner lip and outer lip meets.Holotype (SC 868709) length 2.58mm, breadth 1.23mm; length of aperture 0.90mm, breadth of aperture 0.85mm. Paratype (12 specimens): length 2.70 - 3.00 mm, breadth 1.20 -1.40mm; length of aperture 0.90 - 1.00mm, breadth of aperture 0.90 - 1.00mm. Collected from Xiushan (28°5'N, 109°E), Sichuan Province, on June 22nd, 1986.The species is similar to none of those published in genus Tricula.5. Tricula elongata sp. nov. (fig. 9 - 11)Shell long and thin, somewhat long-conical. Whorl 7, slightly convexed, taking the shape of cylinder. Below every suture is a bond parallel to it. Aperture is like a pear. Outer lip straight and not expanding outward; inner lip curved. Radula formula:2-2/2-1-2; 3-1; 10; 0.Holotype (SC 868710) length 3.25mm, breadth 1.18 mm; length of aperture 0.9mm, breadth of aperture 0.87mm. Paratypes (10 specimens): length 2.90 - 3.70 mm, breadth 1.00 - 1.50mm; length of aperture 0.90- 1.40mm, breadth of aperture 0.80- 1.00 mm. Collected from Kai- xian (31°13'N, 108°3'E), Sichuan Province, on July 7th, 1986.The species is similar to T. odonta, but different from the latter in teeth appeared at the upper part of the inner aperture, and the radula formula.6. Tricul