中国有壳变形虫Argynnia(Vucetich,1974)属的修订及若干环境重建问题探讨

摘要

Testate amoebae are unicellular protists that build a test( shell) ,in which a single amoeboid cell is enclosed. They occur worldwide in a range of terrestrial, wetland, freshwater and even marine habitats, and have proven to be excellent paleoenvironmental proxies in peats and lakes. In protist diversity, testate amoebae occupy a special position due to their particularly conspicuous shell morphology and their important role in nutrient cycling and energy fluxes within microbial food webs. Although most testate amoebae species are generally supposed to have a cosmopolitan distribution, some species are classical examples of local endemism in free-living protozoa and this question is thus debated. Previous morphological and molecular studies justified that genus Argynnia Vucetich,1974 is different from genus Nebela Leidy,1874. However,genus Argynnia is still included in genus Nebela in Chinese testate amoeba taxonomy. Our first goal is to draw attention of Chinese testate amoeba researchers in the current taxonomy of this group, in which the genus Argynnia is separated from genus Nebela combining previous morphological and molecular studies.In China and even in Asia, research on testate amoebae in peatland ecosystems have only began in recent years. Two species belonging to this genus have been observed in China; Argynnia caudata ( Leidy 1876) and A. Dentistoma ( Penard 1890). Possible problems in environmental reconstructions using testate amoeba based transfer functions as well as estimates of global testate amoeba biodiversity caused by taxonomic inconsistency are also discussed, illustrating the necessity for a major taxonomic effort for this group toward a high bioindicator value.%有壳变形虫是一类具外壳的陆相淡水根足纲(Rhizopoda)原生动物,广泛栖息于湖泊、泥炭、沼泽、土壤等各种淡水潮湿环境,由于其壳体具有很好的抗腐蚀性而在沉积物中保存下来,近年来广泛应用于泥炭和湖泊湿地的古环境重建研究中.大部分有壳变形虫是世界广泛分布的,但是也有一些种类具有一定的地带性分布格局.形态学和分子生物学的研究均已表明阿吉尼亚虫属(Argynnia Vucetich,1974)与梨壳虫属(Nebela Leidy,1874)有较大差别,而我国传统的有壳变形虫分类系统仍将它们统一划为梨壳虫属(Nebela).本文在对神农架大九湖泥炭湿地有壳变形虫标本形态学观察的基础上,结合前人研究资料,将阿吉尼亚虫属(Argynnia)从梨壳虫属(Nebela)中分离出来,修正了我国传统的分类系统,并讨论了其生物地理学意义,目前在我国发现该属的2个种,即具尾阿吉尼亚虫Argynnia caudata( Leidy,1876)和齿口阿吉尼亚虫Argynnia dentistoma( Penard,1890).本文还探讨了因有壳变形虫分类标准的差异可能引起的生态学转换函数和古环境重建问题.