Comparative Study on Morphology of Radula of Pomacea canaliculata, P. maculata and Cipangopaludina chinensis
YE Miao;FAN Tian-Qi;CHEN Lian;CHEN Yu;ZHU Shan-Liang;WU Jun;CHEN Gan;XU Hai-Gen;LIU Yan;College of Life Sciences, Nanjing Normal University;College of Life Sciences, Chemistry and Chemical Engineering,Jiangsu Second Normal University;Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection;
Radula as a unique feeding organ is a useful morphological character to identify molluscs. The scanning electron microscopy(SEM) was used for comparison of radula′s morphology of two invasive species Pomacea canaliculata, P. maculata and one native species Cipangopaludina chinensis. The radulae were extracted from four individuals of each apple snails and three individuals of C. chinensis. Surrounding tissue on the radula was removed manually and then placed in 10% sodium hydroxide for approximately 24 hours to remove any remaining tissue. The radula was then dried briefly and fixed on the copper plate and coated with gold. A series of parameters of the central teeth(Fig. 1) from the three species were measured by the software Smile View. The data were analyzed by Statistica 10.0 software package. Results suggested that the radular formula of the three species was 2·1·1·1·2, including one central tooth, one lateral tooth and other two marginal teeth on each side(Fig. 3a, e, i). The main discrepancy between the two apple snails was the central teeth. The first cusp of the central tooth of P. canaliculata was shorter and wider, not as sharp as that of P. maculata(Fig. 3b, f). There were significant differences in the ratio of the length of the first cusp/the width of the central tooth, and the width of the first cusp/the width of the central tooth between the two apple snails(P 0.001, Table 2). The morphology of lateral tooth and marginal tooth for the two apple snails were similar(Table 1). However, the number and morphology of the central teeth, lateral teeth and marginal teeth were different among these three species(Table 1, Fig. 3). The first cusp of the central tooth was triangle, and three small cusps arranged symmetrically on both sides between the two apple snails. The species of C. chinensis had a short, broad, square cusp of the central tooth, bounded by four short, pointed denticles on each side. There were one small sharp cusp inside the big cusp of lateral teeth and two small cusps outside of that in the two apple snails. Three small serrated cusps were observed beside the big cusp of lateral teeth in C. chinensis. The inner and outer marginal teeth were similar in the two apple snails. The central cusp of the marginal tooth was sharp, with a small cusp near it. The central cusp of the inner marginal tooth was extruded in C. chinensis, and the outer marginal tooth had 8﹣10 small pectinate cusps. There were significant differences in the ratio of the width of the first cusp, the length of the first cusp, the length of the second cusp, as well as the width of the second cusp to the width of the central teeth between apple snails and C. chinensis(Table 2). The morphology of the radula is related to diet in order to adapt a wide variety of foods. The two apple snails were polyphagous, mainly feeding on vegetal(primarily young rice-crops) and animal matter, while C. chinensis ate microorganisms in the soil and humus phytoplankton in the water. Different feeding strategies could be one of the factors influencing interspecific differences in radula.
【Fund】： 国家自然科学基金项目(No.31100274);; 江苏省自然科学基金项目(No.BK20131087);; 江苏省高校自然科学基金项目(No.15KJB180004)
【CateGory Index】： Q954
【CateGory Index】： Q954